JP2022071186A - Magnetic tape and tape cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic tape and a tape cartridge that enable high storage density.

SOLUTION: A magnetic tape 10 includes a base material 12, a magnetic layer 16 formed on a first surface side of the base material, and a base layer formed between the base material and the magnetic layer. The magnetic layer contains magnetic particles. The magnetic particles include barium ferrite particles or strontium ferrite particles. The magnetic layer includes a servo track containing servo patterns and non-pattern areas, the servo pattern has a plurality of servo marks each containing a pattern residual magnetization of a first directional octant, the non-pattern area has a non-pattern residual magnetization of a second directional octant, the first directional octant is located in a region between a vertical plane vertical to both the base material and the length of the base material and a first plane of a longitudinal plane parallel to the base material, and the second directional octant is located in a region between the vertical plane and a second plane of the longitudinal plane.

SELECTED DRAWING: Figure 2A

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present disclosure relates to magnetic tapes and tape cartridges.

Magnetic data recording media such as magnetic tapes and magnetic disks are commonly used for storing and retrieving data. Magnetic data recording media can be classified as longitudinal or vertical. Most conventional magnetic media are longitudinal. For media in the longitudinal direction, the maximum magnetic residual magnetization can be obtained in a direction substantially parallel to the plane of the medium. That is, in a longitudinal medium, the magnetic priority axis orientations of the individual magnetic domains are parallel or nearly identical to the surface of the medium and the direction of media movement. On the other hand, in a vertical medium, the maximum remanent magnetization of the magnetic particles is possible perpendicular to the surface of the medium. That is, in a vertical medium, the magnetic priority axis orientation of the individual magnetic domains is predominantly perpendicular to the surface of the medium. However, the magnetic medium can have particles that can have both significant longitudinal and significant vertical components in their orientation. Vertical media generally allow much higher storage densities than can be achieved with longitudinal media.

Magnetic recording media generally have a series of transitions between different magnetization regions. The different magnetization regions can encode a series of bits representing a value of "0" or "1". The magnetically oriented regions may be aligned on the data track that divides the magnetic medium. The recording head of a magnetic drive, such as a tape drive or disk drive, encodes the data by selectively orienting various magnetic regions on the medium for later storage of the data in the magnetic storage medium. The read head or transducer head of the magnetic drive is positioned relative to the data track for later detection of the area, and the drive can interpret the detected area and retrieve the data.

During data storage and restoration, the head must place each data track and follow the path of the data track exactly along the surface of the media. Servo techniques have been developed to facilitate accurate positioning of the transducer head with respect to the data track. Servo pattern refers to a signal or other recording mark on a medium used for tracking purposes. That is, the servo pattern is recorded on the medium and a reference point for the data track is provided. The servo read head has a constant displacement with respect to the transducer head that reads the data track. The servo read head can read the servo pattern and the servo controller interprets the detected servo pattern and generates a position error signal (PES). The PES is used to adjust the servo pattern for the data track and the lateral distance of the servo read head to the transducer head, which allows the transducer head to effectively read and / or write data to the data track. , Properly positioned along the data track.

In some data recording media such as magnetic tape, the servo pattern is stored in a special track on the medium called a "servo band". The servo band serves as a reference for the servo controller. Multiple servo patterns can be defined in the servo band. Some magnetic media include a plurality of servo bands, and the data band is arranged between the servo bands.

One type of servo pattern is a time-based servo pattern. Time-based servo techniques refer to servo techniques that identify head positions using non-parallel servo marks and time or distance variables. The time offset between the detections of two or more servo marks can be converted to PES, which defines the lateral distance of the transducer head to the data track. For example, given a constant velocity magnetic tape formed by the servo pattern "/ \", if the readhead is located towards the bottom of the pattern "/ \", then the marks "/" and the mark "\" The time between detections is long and short if the readhead is located towards the top of the pattern "/ \". Given a constant velocity of the magnetic medium, the defined time between the detected servo signals can correspond to the center of the pattern "/ \". By arranging the center of the pattern "/ \", it is possible to identify the known distance between the center of the servo band and the data track. Time-based servo patterns are commonly implemented on magnetic tape media, but may also be useful in other media.

In general, the present disclosure relates to magnetic recording media such as magnetic tapes, and techniques for erasing and writing magnetic storage tapes that define or have a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. .. Magnetic storage tapes that exhibit a larger vertical angular ratio or vertical anisotropy include magnetic particles that can be magnetically oriented in any direction. That is, these magnetic particles may be magnetically oriented parallel to the length of the magnetic tape and perpendicular to the length of the magnetic tape, or both perpendicular and longitudinal components to the orientation. It may be oriented with. This disclosure describes examples of magnetic tapes with different magnetic orientations in bias and servo patterns, as well as various techniques for producing such orientations.

For example, the magnetic tape may be biased to define residual magnetization with orientation or orientation with vertical and longitudinal components. Two heads located on opposite sides of the tape or one head tuned to a particular distance from the tape can be used to generate a bias in either the vertical or longitudinal direction. The servo pattern can be written to the magnetic tape with a magnetic orientation opposite to the remaining bias on the servo track, eg, a remanent magnetization that is substantially perpendicular to the magnetic tape. Bias in one of the eight directional octets, for example one of the nonzero vertical and longitudinal components, can also be generated with a single head. The servo pattern may be written, or the residual magnetization of the servo mark may be oriented from the directional octet of bias magnetization to the generally opposite directional octet.

Magnetic tape can also include bias and servo patterns written by other techniques. As the tape passes through the write head, a single write head can continuously bias the magnetic tape and write the servo pattern to the magnetic tape. In this continuous write technique, the write head alternates the direction of the magnetic field so that the trailing edge of the alternating magnetic field creates a bias on the tape or writes a servo mark with a residual magnetization that is substantially opposite to this bias. You may do it.

Magnetic tapes with a larger vertical angular ratio can also contain symmetric servo marks, which can collectively define the servo pattern. The gap width of the magnetic head can be sized to be approximately equal to the length of the servo mark. When the magnetic tape passes near the magnetic head, a short-term current pulse can be applied to the magnetic head to generate a short magnetic field. Since the magnetic field is applied to the magnetic tape in such a short period of time, the residual magnetization of the magnetic tape can reflect the magnetic field pattern. That is, the magnetic orientation of the created servo mark may be substantially symmetrical from one end of the servo mark to the other end of the servo mark.

In one example, the present disclosure comprises a substrate and a magnetic layer formed on the substrate, comprising a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. A data storage tape including a servo track on a magnetic layer is described. The data storage tape is also a servo pattern in a servo track, the servo pattern containing a plurality of servo marks each having a pattern residual magnetization in a first direction substantially perpendicular to the substrate, and a plurality of servo marks. A non-patterned region in the servo track located immediately next to and in between, which is substantially perpendicular to the substrate and defines the non-patterned remanent magnetization in the second direction opposite to the first direction. Further includes areas.

In another example, the present disclosure is a step of passing a magnetic tape near a magnetic head, wherein the magnetic tape has a magnetic square ratio greater than 50% and a longitudinal square ratio less than 50%. A step that includes a layer, a servo track, and a data track, a step that generates a first magnetic field in a first direction along a magnetic tape having a magnetic head, and a second along the magnetic tape by the magnetic head. A method including a step of alternately performing a step of generating a second magnetic field in the direction of the above and a step of generating a second magnetic field will be described.

In a further example, the present disclosure is a tape drive configured to run a magnetic tape, which is magnetic with a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. A tape drive, including a layer, a servo track, and a data track, and a step that generates a first magnetic field along the magnetic tape in a first direction while the magnetic tape is running near the magnetic head. , A system comprising a magnetic head configured to alternate between steps of generating a second magnetic field in a second direction along a magnetic tape.

In another example, the present disclosure is a symmetric servo mark that defines a mark length that is approximately equal to the gap width of the write head by generating a short-term magnetic field with the step of passing the magnetic tape near the write head. Describes a method including a step of making a magnetic tape.

In a further example, the present disclosure comprises a tape drive running a magnetic tape and a symmetric servo mark that creates a magnetic field across the gap width in a short period of time to define a mark length approximately equal to the gap width of the writehead. Describes a system that includes a write head that is configured to create on magnetic tape.

In a further example, the present disclosure is recorded on a substrate and a magnetic layer formed on the substrate and containing a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. A data storage tape containing a symmetric servo mark is described. The symmetric servo mark is substantially perpendicular to the substrate at the first end of the symmetric servo mark and at the first remanent magnetization directed towards the substrate and at the second end of the symmetric servo mark. Includes a second remanent magnetization that is substantially perpendicular to the substrate and away from the substrate.

In another example, the present disclosure describes a data storage tape comprising a substrate and a magnetic layer formed on the substrate. The magnetic layer comprises a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%, as well as residual magnetization in a direction substantially perpendicular to the substrate.

In a further example, the disclosure is a step of passing the magnetic tape through at least one magnetic field, where the magnetic tape has a vertical square ratio greater than 50% and a longitudinal square ratio less than 50% with the substrate. A method comprising a step comprising a magnetic layer comprising, and a step of forming a residual magnetization in the magnetic layer in a direction substantially perpendicular to the substrate using at least one magnetic field will be described.

In a further example, the present disclosure comprises a magnetic tape containing a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%, and a tape drive configured to run the magnetic tape in the first direction. And a system including at least one magnetic head. The at least one magnetic head is configured to generate remanent magnetization in a direction substantially perpendicular to the magnetic tape.

In another example, the present disclosure is a substrate and a magnetic layer formed on the substrate, comprising a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. And the data storage tape including the servo track on the magnetic layer are described. The data storage tape further includes a servo pattern in the servo track, the servo pattern comprising multiple servo marks, each of which is in contact with a vertical plane perpendicular to both the substrate and the length of the substrate. The pattern residual magnetization in the first directional octet placed on the first plane of the longitudinal plane parallel to the substrate, and the non-patterned region in the servo track, in contact with the vertical plane, first. It comprises a non-patterned region with a non-patterned residual magnetization in a second directional octet located on a second plane of a longitudinal plane opposite to the plane of.

In a further example, the present disclosure comprises a substrate and a magnetic layer formed on the substrate, comprising a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. , A data storage tape containing a servo track on a magnetic layer. The data storage tape further includes a servo pattern in the servo track, the servo pattern comprising multiple servo marks, each of which is in contact with a longitudinal plane parallel to the substrate and of the substrate and substrate length. The pattern residual magnetization of the first directional octet placed on the first plane of the vertical plane perpendicular to both, and the non-patterned region in the servo track, in contact with the longitudinal plane, in the first direction. It has a non-pattern residual magnetization in the second directional octet, located on the second plane of the vertical plane opposite to the first directional octet.

In a further example, the present disclosure is a step of forming multiple servo marks on the servo track of a magnetic layer of magnetic tape, where the magnetic layer is formed on a substrate with a vertical square ratio greater than 50% and 50. Described is a method comprising a step, comprising a longitudinal square ratio of less than%. The servo track comprises a non-patterned region with bias magnetization, and the plurality of servo marks are configured to generate a servo signal by a read head configured to identify multiple servo marks, unlike bias magnetization. The servo signal contains a waveform with a unipolar pulse when the residual magnetization contains a vertical component opposite to the vertical component of the bias magnetization, and the residual magnetization is with the longitudinal component of the bias magnetization. A waveform with a bipolar pulse when the matching longitudinal component and the longitudinal component of the residual magnetization have the opposite longitudinal component of the bias magnetization, and the vertical and longitudinal components where the bias magnetization is substantially randomized. When having a waveform with a substantially symmetrical bipolar pulse.

It is a schematic cross-sectional view of an exemplary magnetic storage medium.

It is a conceptual diagram of an example of the direction of residual magnetization in one of eight octets after applying a magnetic field to a magnetic storage tape.

It is a schematic diagram of an exemplary hysteresis curve defining the square ratio of the magnetic layer of a magnetic storage medium.

It is a conceptual diagram of an exemplary servo writing system.

It is a conceptual diagram of an exemplary servo pattern in a servo track of a magnetic storage tape.

It is a conceptual diagram of an exemplary data storage system using a magnetic storage tape.

FIG. 3 is a conceptual diagram of an exemplary bias and servo pattern in longitudinal magnetic orientation. It is a conceptual diagram of an exemplary bias and servo pattern in the magnetic orientation in the longitudinal direction and a graph of the corresponding readout signal.

It is a conceptual diagram of an exemplary bias and servo pattern in vertical magnetic orientation. It is a conceptual diagram of an exemplary bias and servo pattern in vertical magnetic orientation and a graph of the corresponding readout signal.

It is a figure which shows various directions of the residual magnetization of a bias in a magnetic memory tape.

A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet VIII is shown, along with a graph of the corresponding readout signal. A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet VIII is shown, along with a graph of the corresponding readout signal.

A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional eight-quarter IV is shown, along with a graph of the corresponding readout signal. A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional eight-quarter IV is shown, along with a graph of the corresponding readout signal.

A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet I is shown, along with a graph of the corresponding readout signal. A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet I is shown, along with a graph of the corresponding readout signal.

A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of a directional octagonal circle V is shown, along with a graph of the corresponding readout signal. A conceptual diagram of an exemplary magnetic medium containing a magnetic bias of a directional octagonal circle V is shown, along with a graph of the corresponding readout signal.

A graph of the corresponding readout signal is shown, along with a conceptual diagram of an exemplary magnetic medium that is substantially free of magnetic bias from randomized magnetic particles. A graph of the corresponding readout signal is shown, along with a conceptual diagram of an exemplary magnetic medium that is substantially free of magnetic bias from randomized magnetic particles.

It is a conceptual diagram of an exemplary magnetic medium including the residual magnetization of the servo mark by the leading and trailing edges of the magnetic field and the graph of the corresponding readout signal.

It is a conceptual diagram of an exemplary magnetic medium including the remanent magnetization of a servo mark by continuously writing the trailing edge of a magnetic field and the graph of the corresponding readout signal.

It is a conceptual diagram of a single magnetic head which writes a servo pattern by alternately changing the direction of a magnetic field. It is a conceptual diagram of a single magnetic head which writes a servo pattern by alternately changing the direction of a magnetic field.

It is a conceptual diagram of the gap width of the magnetic head and the servo mark of the length almost equal to the gap width. It is a conceptual diagram of the gap width of the magnetic head and the servo mark of the length almost equal to the gap width.

It is a conceptual diagram of a magnetic head which forms a symmetric servo mark having a magnetic field corresponding to the length of a symmetric servo mark.

FIG. 3 is a timing diagram of a current pulse that generates a magnetic field used to form a symmetric servo mark.

FIG. 3 shows a conceptual diagram of a magnetic medium with a bias and a symmetric servo mark created on the corresponding readout signal. FIG. 3 shows a conceptual diagram of a magnetic medium with a bias and a symmetric servo mark created on the corresponding readout signal.

FIG. 6 is a flow diagram illustrating an exemplary technique for producing a substantially longitudinal or vertical bias on a magnetic tape with a larger vertical angular ratio.

It is a flow diagram which shows an exemplary technique for generating a bias in a unidirectional octet, and forming a servo mark having a residual magnetization of a directional octet different from the bias.

It is a flow diagram which shows the exemplary technique of writing a servo mark by continuously biasing by changing the direction of a magnetic field alternately.

It is a flow diagram which shows an exemplary technique for forming a symmetric servo mark on a magnetic storage tape.

In general, the present disclosure relates to magnetic recording media such as magnetic tapes, which have a vertical square ratio greater than a longitudinal square ratio. Various techniques have been described for erasing, eg, biasing, and writing to magnetic storage tapes that define a larger vertical square ratio. As a result of one or more of these techniques, magnetic storage tapes can include different patterns of residual magnetization along the length of the magnetic tape, such as servo patterns, thereby providing various data storage drives. Allows data to be stored on magnetic storage tape.

As used herein, a larger vertical square ratio generally refers to the magnetic particles of a magnetic tape that can be magnetically oriented in any three-dimensional direction. The magnetic orientation of these magnetic particles can be described, for example, as a vector having a vertical component perpendicular to the plane of the magnetic tape and a longitudinal component parallel to the plane of the magnetic tape, for example. The magnetic particles of a magnetic tape that define a larger vertical square ratio (ie, "vertical magnetic tape") may have a tendency to orient somewhat perpendicular to the magnetic tape, but a larger vertical square. The magnetic particles showing the ratio can be isotropic in some materials used for magnetic tape. In contrast, conventional magnetic storage tapes have magnetic particles that are oriented substantially parallel to the plane of the magnetic storage tape, if not perfect.

The advantage of magnetic storage tapes with a larger vertical square ratio is higher data storage capacity. However, the drawback of this type of magnetic medium is that magnetic particles allow complex magnetic orientation. These complex orientations can create a non-conventional magnetic field and reduce the signal-to-noise ratio associated with reading marks on magnetic tape, which can result in data loss during such readings. be. Therefore, accurate bias and write techniques can be used to achieve a larger signal-to-noise ratio for the information written on the vertical magnetic tape. The technique of this disclosure is particularly useful for creating servo patterns on magnetic tapes typically located in servo bands located between data bands.

In one example, the magnetic tape may be biased, ie erased, substantially either vertically or longitudinally. This bias can also be described as the residual magnetization that remains in the magnetic layer of the tape after the magnetic field is applied to the tape. This substantially vertical or substantially longitudinal residual magnetization may be generated by two magnetic heads or one magnetic head. In a two-head bias system, each head is located on the opposite side of the magnetic tape. Each head applies a magnetic field directed in the same direction along the tape to create a substantially longitudinal bias. Conversely, each head applies a magnetic field directed in the opposite direction along the tape to create a substantially vertical bias. That is, a particular magnetic orientation may be generated on a vertical magnetic tape with different parts of a single magnetic field. In either the vertical bias or the longitudinal bias, the corresponding servo pattern (eg, multiple servo marks) can be written on the bias to produce a pattern residual magnetization that is substantially the opposite of the bias.

In another example, the magnetic tape can include a bias or remanent magnetization in the magnetic orientation having one of eight directional octets, eg non-zero vertical and longitudinal components. This type of bias may be generated by a single head, depending on the direction of the magnetic field and which side of the magnetic tape the head is on. Servo patterns are generally directional octets, generally opposite to those of bias octets, such that signals are generated at the interface between two different directions of servo pattern remanent magnetization and non-patterned or bias remnant magnetization. Written.

Bias and servo write, such as how to write a servo pattern to the servo track of a magnetic tape, can be completed in two different magnetic heads and / or two separate steps, but a single write head in one step. Can be configured to create bias and servo patterns with. As the tape passes through the write head, a single write head can continuously bias the magnetic tape and write the servo pattern to the magnetic tape. In this continuous writing technique, the write head can alternate the direction of the magnetic field so that the trailing edge of the alternating magnetic field biases the tape and writes the servo pattern. That is, a bias is generated in one direction of the magnetic field and a servo pattern is generated in the other direction of the magnetic field. Therefore, bias and servo writing can be completed in a single path of magnetic tape near the write head.

A magnetic field can also be applied to a vertical magnetic tape to create a symmetric servo mark, eg, part of a servo pattern. The gap width of the magnetic head, or the distance traveled by the magnetic field, can be sized to be approximately equal to the length of the servo mark. When the magnetic tape passes near the magnetic head, a short-term current pulse is applied to the magnetic head to generate a short-lived magnetic field. This short current pulse can generally occur in a short period of time between 10 and 50 nanoseconds. In one example, the short period may be about 30 microseconds or less. For a short period of time, the magnetic tape may at least partially depend on the speed at which it passes through the magnetic head, for example, a faster tape speed may require a shorter current pulse. Since the magnetic field is applied to the magnetic tape in such a short period of time, the resulting magnetic orientation in the magnetic tape over the length of the servo mark can be substantially equivalent to the magnetic field. That is, the magnetic orientation of the created servo mark is substantially symmetrical from one end of the servo mark to the other end of the servo mark.

FIG. 1 is a schematic cross-sectional view of an exemplary magnetic storage medium 10. As an example, the magnetic tape 10 may be a magnetic storage medium or a magnetic storage tape capable of storing data. The magnetic tape 10 includes a base material 12. The base material 12 defines a first surface and a second surface opposite to the first surface. The non-magnetic base layer 14 is formed on the first surface of the base material 12. The underlayer 14 contacts the substrate 12 on one surface and defines the coating surface on the opposite surface. The backing layer 20 can be formed on the second surface of the base material 12. Further, the magnetic layer 16 is formed on the coating surface defined by the base layer 14. The magnetic layer 16 defines the recording surface 18. The recording surface 18 may be the outermost surface of the magnetic recording medium 10, or may be the surface that the recording head crosses during a data reading or writing operation. In addition to one or more data tracks, the magnetic layer 16 can support one or more servo tracks that allow the read / write head to align with the data tracks.

The substrate 12 functions as a supporting carrier for the magnetic recording medium 10 and can be formed from any suitable material. For example, the base material 12 can include glass, plastic, organic resin, metal and the like. In some cases, the substrate 12 can include a polymer film. Any suitable polymer or combination of polymers can be used. The polymer can be selected to impart mechanical or electromagnetic properties to the magnetic recording medium 10 for chemical compatibility, or based on other properties. Polymers such as flexibility, rigidity, electrical resistance, and conductivity are known in the art. Suitable polymers include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), blends or copolymers of polyethylene terephthalate and polyethylene naphthalate, polyolefins (eg polyethylene, polypropylene, polystyrene), cellulose derivatives, polyamides, polyimides, etc. And combinations thereof. In addition, the substrate 12 may contain various other polymers, binders, or additives such as carbon black and silica.

The backing layer 20 can be formed on at least a part of the back surface of the base material 12. The backing layer 20 can have a controlled surface roughness that affects the take-up and rewind properties of certain types of magnetic recording media, such as magnetic tape. The backing layer 20 can also provide dimensional stability to the magnetic tape 10, for example by minimizing cupping and curing of the edges of the magnetic tape 10. In some examples, the backing layer 20 may include components that provide electrical resistivity to the composite tape 10. For example, the backing layer 20 can contain carbon black. The electrically resistant backing layer can improve the electromagnetic properties of the magnetic tape 10. Further, the backing layer 20 may contain a binder component. Any suitable binder component that is chemically compatible and mechanically stable can be used. In some cases, the binder component may include polyurethanes and polyolefins, phenoxy resins, nitrocellulose, polyvinyl chloride, and combinations thereof. The backing layer 20 may contain additional polymers, pigments, binders, solvents and additives, as will be appreciated by those skilled in the art.

The magnetic layer 16 is formed on the base material 12. Generally, the magnetic layer 16 contains a plurality of magnetic particles contained in the binder. Additives such as surfactants, wetting agents, lubricants, and abrasives are added to the plurality of magnetic particles to improve the quality and performance of the magnetic tape 10 during data recording and storage, thereby, for example, magnetic. The magnetic orientation of the magnetic particles in the layer 16 may be generated and retained. Various components of the composition of the magnetic layer 16 can be combined and applied onto an article to form the magnetic layer 16 defining the recording surface 18.

Generally, the magnetic layer 16 contains a plurality of magnetic particles forming a pigment. Different magnetic particles define different shapes, and the shape profile can affect the storage density or storage quality of the formed magnetic tape. As an example, magnetic particles can define needle-like or needle-like, plaque, low aspect ratio shapes, or magnetic particles can even define amorphous shapes. The magnetic layer 16 can contain magnetic particles of any suitable shape. For example, the magnetic layer 16 can contain needle-like particles. Typical needle-like particles are ferromagnetic or ferric iron oxide such as γ-iron oxide (γ-Fe2O3), iron, cobalt and nickel composite oxides, and various ferrite and metallic iron, cobalt or alloy particles. Contains particles of. However, non-needle particles may exhibit better filling morphology than needle particles. For example, when the platen particles are oriented perpendicular to the surface of the substrate 12 rather than longitudinally, the platen particles may exhibit a denser filling morphology than the needle particles. As another example, low aspect ratio particles do not naturally stack on top of each other, resulting in a more uniform magnetic recording surface.

Therefore, the magnetic layer 16 can also include particles such as small plate particles and low aspect ratio particles. Suitable platen or low aspect ratio particles are of various iron, cobalt, and nickel bases, including iron, cobalt and nickel alloys, and iron and / or cobalt and nickel and oxygen and / or nitrogen compounds. Can contain particles. In some examples, the plaque or low aspect ratio particles can include particles containing a hexagonal lattice structure. For example, some ferrites, such as barium ferrite (eg, hexagonal barium ferrite), include a hexagonal lattice structure. Another example of small plate particles suitable for use in the magnetic tapes of the present disclosure is strontium ferrite particles.

The magnetic tape 10 is only one configuration example of the magnetic tape. Alternatively, the other magnetic tape may not include the backing layer 20 or may include a plurality of backing layers 20. In some examples, the magnetic layer 16 may be bonded directly to the substrate 12 without the underlying layer 14. In another example, the magnetic tape 10 may include a plurality of magnetic layers 16 that may or may not include a cover layer deposited on one or more magnetic layers 16. Generally, it can be explained that the magnetic layer 16 is formed on the base material 12. The term "formed" refers to an example in which one or more layers are placed between the magnetic layer 16 and the substrate 12, or the magnetic layer 16 is formed directly on the substrate 12. Alternatively, other examples that are directly attached to the substrate 12 are included. Thus, the examples described herein that include a magnetic layer formed on a substrate may or may not have an additional layer placed between them.

FIG. 2A is a conceptual diagram of an exemplary direction of the residual magnetization 22 after applying a magnetic field to the magnetic particles in the magnetic layer 16. The magnetic tape 10 includes a magnetic layer 16 formed on the base material 12. The magnetic tape 10 may include an additional backing layer, base layer or intermediate layer (eg, between the magnetic layer 16 and the substrate), as described above with respect to FIG. It may be generally described as including the magnetic layer 16 formed on the 12 and the base material 12. Each of the magnetic particles in the magnetic layer 16 can be described as having a magnetic orientation 22 (ie, residual magnetization resulting from the applied magnetic field). Further, a plurality of magnetic particles may generally be described in a combination having a residual magnetization 22. Since some of the magnetic particles may be oriented in a direction different from the general magnetic orientation, the generally described residual magnetization 22 of the magnetic particles is the magnetic orientation of substantially all the magnetic particles or the magnetic layer 16. It may point to the collective direction of the magnetic particles inside.

The remanent magnetization 22 is generally used in the present disclosure to describe in the magnetic layer 16 a vector of magnetic alignment of magnetic particles caused by an applied magnetic field. In general, a coordinate system as shown in FIG. 2A can be used to identify the direction of the residual magnetization 22 with respect to the substrate 12 of the magnetic tape 10. The coordinate system is described in a cross section in the length direction of the magnetic tape 10, and as indicated by the arrow 24, the magnetic tape 10 passes through the read / write head in the direction.

As shown in the example of FIG. 2A, a part of the magnetic layer 16, that is, the residual magnetization 22 of one or more magnetic particles is aligned at about 25 degrees. This alignment or orientation of the remanent magnetization 22 is from the substrate 12 towards the direction of magnetic tape travel as indicated by the arrow 24. The remanent magnetization 22 can also be described as having both non-zero longitudinal and vertical components. In fact, the 25 degree residual magnetization 22 indicates that the longitudinal component is smaller than the vertical component of the vector. Therefore, the residual magnetization 22 is also within the range of the directional eight-quarter circle I.

Directional octagons I, II, III, IV, V, VI, VII and VIII may be used to indicate the direction of the residual magnetization 22. The directional octet describes a vector space in which the remanent magnetization 22 can be directed. Each octuple is spatially separated from the magnetic tape 10 in terms of surface. The longitudinal plane 21 is parallel to the substrate 12 and bisects the magnetic layer 16. The vertical surface 23 is orthogonal to the base material 12 and bisects the cross section of the magnetic layer 16. That is, the vertical surface 23 is perpendicular to the lengths of the base material 12 and the base material 12. Further, the diagonal surfaces 25 and 27 further divide the vector space to create an octagonal boundary. In this way, each of the faces 21, 23, 25, and 27 intersect at a common line to create the boundaries of each of the eight octets described herein. In some examples, the remanent magnetization 22 located in one of the planes can be described as being within the range of two octets in contact with the plane.

The directional octets may be evenly separated by surfaces 21, 23, 25, and 27 such that each octet defines an angle of approximately 45 degrees. However, in another example, the surfaces can be oriented in different directions such that the surfaces 25 and 27 have an angle of 20 to 70 degrees with the longitudinal surface 21. In one example, the planes 25 and 27 are at angles 21 and 30 degrees in the longitudinal direction, respectively, so that the octets I, IV, V and VIII touch the vertical plane 23 and form an angle of 60 degrees with the vertical plane 23, respectively. Make up. In another example, the planes 25 and 27 are longitudinal planes 21 and 60 degrees, respectively, so that the octagonal circles I, IV, V and VIII touch the vertical plane 23 and form an angle of 30 degrees with the vertical plane 23, respectively. Make an angle of.

As shown in FIG. 2A, the directional octet I is between 0 and 45 degrees, the directional octet II is between 45 and 90 degrees, and the directional octet III. Is between 90 degrees and 135 degrees, and the directional octet IV may be between 135 degrees and 180 degrees. Further, the directional octet V is between 180 and 225 degrees, the bidirectional octet VI is between 225 and 270 degrees, and the directional octet VII is 270 degrees. Between degrees and 315 degrees, the directional octet VIII may be from about 315 degrees to 360 degrees (ie, 0 degrees). That is, each directional octet may be located in the region between the faces 21, 23, 25, and 27.

The exact degree of the residual magnetization 22 may be less important than the general orientation with respect to the substrate 12, so in some examples a directional octagon to illustrate the residual magnetization of the bias and servo marks. Can be used. Each directional octet can be centered around a particular angle, for example 22.5 degrees, with respect to the directional octet I, whereas the directional octet is a surface, as shown in FIG. 2A. It does not need to be centered between 21, 23, 25, and 27.

In some examples, the remanent magnetization 22 may exist along one of the planes 21, 23, 25, and 27 instead of one of the directional octets. When the residual magnetization 22 is, for example, 90 degrees or 270 degrees along the surface 21, the residual magnetization 22 is defined as the longitudinal direction because the direction of the residual magnetization 22 is parallel to the surface of the substrate 12 and the magnetic tape 10. can do. On the contrary, since the direction of the residual magnetization 22 is perpendicular to the planes of the base material 12 and the magnetic tape 10, the residual magnetization 22 aligned at, for example, 0 degrees or 180 degrees along the axis 23 is perpendicular. Can be defined.

In another example, the remanent magnetization 22 can be defined as being substantially perpendicular or substantially longitudinal with respect to the surface 23 or 21. The expression "substantially vertical" or "substantially longitudinal" refers to the remnant magnetization 22 within a predetermined angle of each surface, as the remanent magnetization 22 may not be exactly aligned with either the surface 21 or 23. Can be defined. For example, if the remanent magnetization 22 is within about 20 degrees of the surface 23, for example between 20 and 340 degrees, or between 160 and 200 degrees, the remnant magnetization 22 may be substantially vertical. .. The change in residual magnetization 22 that is considered substantially vertical from the surface 23 may generally be less than a change of 45 degrees from the surface 23, for example between 45 and 135 degrees, or between 225 and 315 degrees. Between. The change in remanent magnetization 22 that is considered substantially longitudinal from the surface 21 may generally be a change of less than 45 degrees from the surface 21, eg, between 315 degrees and 45 degrees, or 135 degrees and 225 degrees. Between. However, the substantially vertical or substantially longitudinal residual magnetization 22 of the magnetic layer 16 may be more specifically within 25 degrees of either the surface 21 or 23.

FIG. 2B is a schematic diagram of an exemplary hysteresis curve that defines the squareness of the magnetic layer of a magnetic storage medium. An example of an electromagnetic property that indicates deagglomeration of magnetic particles is the magnetic square ratio. As used herein, the square ratio refers to the ratio of the residual moment to the saturation moment of a magnetic material, which uses a vibrating sample magnetometer (VSM) with a defined saturation field of 10,000 oersted. Can be measured. The residual moment and saturation moment parameters of the magnetic material can be observed on the magnetic hysteresis curve. The hysteresis curve defines how a magnetic material can be magnetically oriented or reoriented in response to the application and removal of a magnetic field. In the example of FIG. 2B, the residual moment _mr refers to the magnetization remaining in the magnetic material after being saturated in a strong magnetic field, and the saturation moment _ms refers to the magnetization in the magnetic material at the time of saturation. Further, the coercive force H _c refers to the magnetic field strength applied to the magnetic material after saturation with a strong magnetic field in the opposite direction, which is just sufficient to reduce the moment m to zero. FIG. 2B also shows the switching magnetic field distribution (SFD), which is a measure of the magnetic field intensity interval, in which the given magnetization is completely reversed and normalized by the coercive force _Hc . The SFD is typically measured as the full width w of the hysteresis curve, which is half the maximum value of the pulse calculated by differentiating the hysteresis curve with respect to the magnetic field H.

The magnetic square ratio is specified by the ratio of the residual moment _mr to the saturation moment _ms (ie, _mr / _ms ) in the exemplary hysteresis curve of FIG. 2B. In some cases, a larger square ratio indicates agglomeration or lamination of smaller magnetic particles than a corresponding magnetic material with a smaller square ratio. Although FIG. 2B shows the general positions of the different hysteresis parameters, the curves are provided only to illustrate the case of general square ratios and is a hysteresis plot of the particular material intended herein. Is not intended to represent.

The hysteresis curve of the magnetic material can be measured in any direction of the magnetic material. For example, a direction parallel to the recording surface of the magnetic recording medium (for example, a direction parallel to the direction in which the substrate is conveyed in the web manufacturing process), a direction perpendicular to the recording surface of the magnetic recording medium, or a recording surface of the magnetic recording medium. The hysteresis curve can be measured in the lateral direction with respect to the above. In addition, the square ratio can be determined for each hysteresis curve measured in each different direction. In general, an increase in the square value in one direction (eg, perpendicular to the surface of the magnetic recording medium) correlates with a decrease in the square ratio in the other direction (eg, parallel to the surface of the magnetic recording medium). The reverse is also true.

The square ratio of a magnetic material can vary, for example, depending on the orientation of the magnetic particles in the material or the orientation of the material itself. One orientation of the square ratio is along the major axis of the recording medium, such as an axis parallel to the length of the magnetic tape or an axis parallel to the direction in which the substrate is transported in the web manufacturing process. Therefore, this type of square ratio can be referred to as a magnetic layer having a longitudinal square ratio greater than a longitudinal square ratio or a vertical square ratio. The hysteresis curve can be determined by measuring the magnetic properties exhibited by the medium when it is oriented in the longitudinal arrangement. Subsequently, the square ratio can be calculated based on the determined hysteresis curve.

As is commonly described herein, the magnetic layer 16 of FIG. 1 can have a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. That is, the magnetic layer 16 can have a larger or larger vertical angular ratio indicating a magnetic medium with vertical anisotropy. In another example, the magnetic layer 16 can have a vertical square ratio greater than 75% and / or a longitudinal square ratio less than 25%. In some examples, the magnetic layer 16 can have a vertical square ratio greater than 90% and / or a longitudinal square ratio less than 10%. In any of these examples, a vertical square ratio greater than 50% allows the residual magnetization of the magnetic layer 16 to be substantially perpendicular to the substrate 12.

FIG. 3 is a conceptual diagram showing an example of a servo writing system 26 that writes a pre-recording servo pattern on a magnetic tape 32. The magnetic tape 32 may be an example of the magnetic tape 10 described with reference to FIGS. 1 and 2. The system 26 includes a servo head module 28, a servo controller 30, and a magnetic tape 32 spooled on spools 34 and 36. The servo head module 28 includes one or more servo heads, that is, magnetic heads, for writing a servo pattern on the magnetic tape 32. The controller 30 controls the magnetic field applied by one or more servo heads of the servo head module 28. The magnetic tape 32 is supplied from the spool 34 to the spool 36, and passes in close proximity to the servo head module 28, for example, by approaching and adjoining the servo head module 28. For example, the magnetic tape 32 may come into contact with one or more servo heads of the servo head module 28 during servo recording.

The servo head module 28 includes an electromagnetic element that generates a magnetic field. In one example, the controller 30 may have a first servo head write on a substantially full servo band, such as one or more servo tracks associated with a magnetic tape 32. Next, the controller 30 can have at least one additional servo head in the servo head module 28 selectively erase the previously recorded servo marks in the servo band. The servo head module 28 can write a servo pattern to one or more servo tracks on a pre-made bias in the magnetic tape 32. Bias may be generated by one or more different bias heads. These different bias heads are magnetic heads that may be independent of the system 26, may be included in the system 26 of a different head module, or may be part of the servo head module 28. In some examples, the bias may be generated by the servo head in the servo head module 28 before or during the writing of the servo pattern.

In another example, the servo band portion of the magnetic tape 32 may be magnetized at random. The random magnetization of the tape 10 can be a substantially zero bias or elimination generated by an alternating magnetic field from one or more magnetic heads. The controller 30 can have at least one servo head in the servo head module 28 write a servo mark in a randomly magnetized servo band.

Generally, the servo head on the servo head module 28 writes or creates a servo pattern having at least three servo marks. For example, the servo head can provide a time-based servo pattern that allows linear position error signal (PES) calculations. In some examples, the servo pattern provides a linear relationship between the PES and the ratio of the time increments to the detection of the servo mark in the servo pattern, and the linear form is calculated by PES (hereinafter referred to as "linear PES calculation"). It can be used for). A typical time-based servo pattern is shown in FIG. In another example, the servo head module 28 is provided with an amplitude-based servo pattern that allows the read / write head to be accurately located on one or more data tracks within the magnetic tape 32. Alternatively, other servo patterns may be included.

One or both of the spools 34 and 36 can be attached to a motor that moves the spools 34 and 36 to run the magnetic tape 32 and allow the magnetic tape to pass near the servo head module 28. The controller 30, or a different control device, can coordinate the travel of the magnetic tape 32 and the generation of a magnetic field with the servo head module 28. This adjustment includes the speed of the magnetic tape 32 and / or the timing of the magnetic field generation by the servo head module 28. The system 26 can be configured to run the magnetic tape in either direction through the servo head module 28 or in only one direction with respect to the servo head module 28.

Although the system 26 is described as being used to form a servo pattern with a plurality of servo marks on the magnetic tape, the system 26 can also generate a magnetic bias on the magnetic tape. When the bias is generated, a servo pattern is formed on the magnetic tape on the magnetic bias. Bias can promote a strong signal-to-noise ratio as it transitions between the bias region in the tape and the servo pattern. Both the bias pattern and the servo pattern can be characterized by residual magnetization in a particular direction with respect to the magnetic tape, as described in FIG. 2A.

In general, the magnetic head of the servo module 28 can generate a magnetic field of any suitable intensity suitable for achieving a particular magnetic orientation. Factors that influence the choice of magnetic field strength include, for example, the types of magnetic particles in the magnetic layer, additional types of components in the magnetic layer composition, and the specific equipment used to apply the magnetic field. Be done. In some examples, the magnetic field strength is correlated with the square ratio of the magnetic layer and may be adjusted to achieve the desired residual magnetization from the magnetic field. In some examples, a magnetic field strength between about 3000 gauss and about 5000 gauss can be applied to the magnetic layer to create a magnetic bias or servo pattern on the magnetic layer of the magnetic tape.

The magnetic fields described herein for forming magnetic bias and / or servo patterns may be applied to the magnetic layer at any suitable point in the manufacturing process, or even at multiple points in the manufacturing process. .. For example, a magnetic field can be applied while the magnetic layer is still wet to rotate the magnetic particles within the layer. After being rotated in a controllable manner, the magnetic particles can exhibit appropriate magnetic anisotropy. In some cases, a magnetic field can be applied immediately after the magnetic layer is formed on the substrate. For example, when a magnetic layer is applied onto a moving web to produce a magnetic recording medium, a magnetic field can be applied immediately after the web exits the coating device to apply the magnetic layer. By applying a magnetic field before the magnetic layer settles and begins to dry, the magnetic particles within the magnetic layer may be more susceptible to rotation and magnetic alignment. As a result, the formed magnetic recording medium may exhibit stronger and more uniform magnetic anisotropy, and magnetic marks (eg, bits of information) available for storing data on the formed magnetic recording medium. May increase the number of areas used to indicate).

FIG. 4 is a conceptual diagram showing a data storage tape 40 including a data track 42, a servo track 44, and a servo track 46. The data storage tape 40 may be an example of the magnetic tapes 10 or 32 of FIGS. 1 to 3. As referred to herein, the servo mark is a continuous shape that can be perceived as the read head passes through the surface of the medium. Time-based servo marks are generally straight lines, but do not necessarily have to be straight lines, and in some examples time-based servo marks can have a zigzag or curved shape. With respect to magnetic tape, servo marks are generally written by a single write gap within the servo head with a single electromagnetic pulse. The term servo mark includes straight servo stripes, including curved servo marks and servo marks of other shapes, for example, each servo mark is a chevron and each servo pattern is a set of nested chevrons. There may be.

The servo pattern includes a plurality of servo marks. Multiple servo marks in a single time-based servo pattern allow the calculation of PES using time measurements between the readhead's detection of servo marks in the pattern. In general, all servo marks in a single servo pattern are written using a single electromagnetic pulse, so tape speed discrepancies during servo writing do not affect the spacing of servo marks in the servo pattern. As referred to herein, a servo frame comprises at least one servo pattern, but a servo frame often comprises two or more servo patterns. As an example, the servo track 44 includes servo frames 48A and 48B (collectively referred to as "frame 48"). Each servo frame 48 includes four servo patterns. Servo patterns in a servo frame having two or more servo patterns are generally written by the same servo head using one electromagnetic pulse for each servo pattern in the servo frame. For example, each of the servo frames 48 was written using four electromagnetic pulses.

Similarly shaped adjacent servo marks of separate servo patterns within the servo frame are generally written using the same write gap. These commonly formed adjacent servo marks of separate servo patterns within the servo frame are referred to herein as bursts. The term burst is based on the signal detected as the head passes through the servo marks that make up the burst. For example, the servo function 48A includes bursts 50A and 50B. In some examples, the servo marks may overlap as well as the servo marks, servo patterns and bursts. For simplicity, FIG. 4 does not show overlapping servo marks, servo patterns, bursts or servo frames.

Each servo frame 48 contains two servo patterns, and each servo pattern contains four servo marks with a single linear mark. For example, the four marks on the burst 50A are linear. All of the servo patterns of the servo band 44 are written by the same servo write head and are substantially the same. The servo track 46 also includes two servo frames 49A and 49B (“frame 49”). Each frame 49 also includes two servo patterns. Like the servo track 44, all of the servo patterns in the servo track 46 are written and identical by the same servo write head. The servo pattern in the servo track 44 is shown inverted with respect to the servo pattern in the servo track 46. However, in other examples, each servo track can have the same or unique servo pattern.

The servo pattern within the servo tracks 44 and 46 facilitates the positioning of the read head or data head with respect to the data track 42 at a known distance from the servo tracks 44 and 46. The position of the read head along one of the head paths 54A and 54B (“path 54”) is determined by measuring the time between detections of the marks forming each servo pattern. Servo marks 52A and 52B (“mark 52”) form a servo pattern within the servo frame 14A. Servo marks 52 have shapes that are not identical in that their geometries are different from each other except that they are simply interchanged in the downtape direction. For example, as shown in FIG. 4, two linear servo marks at different angles with respect to the tape transverse direction have non-identical geometric shapes. Similarly, two non-linear servo marks that have the same general shape at different angles with respect to the crossing tape direction, such as curved servo marks, have non-identical shapes. In contrast, each servo mark on the burst, eg, the four servo marks on the burst 50A, typically has the same shape as the other marks in the burst. When the data storage tape 40 passes through the read head arranged along the head path 54B, the read head first detects the first servo mark of the servo pattern 52A. Next, the first servo mark of the servo pattern 52B of the servo frame 49A is detected by the read head. The time for detecting the first servo mark in the servo pattern 52A and the first servo mark in the servo pattern 52B is shown as "time A" in FIG. From this measurement, the distance between the servo tracks 52A and 52B varies according to the lateral position of the read head path, so that the position of the read head in the servo track 46 can be determined. For example, if the head path 54B is close to the data track 42, the time A will be larger. Similarly, if the head path 54B is further away from the data track 42, the time A will be shorter.

The relationship between the measured time A and the position of the read head in the servo track 46 depends on the tape speed of the data storage tape 40 as the data storage tape 40 passes through the read head. By identifying the position of the head path 16 with respect to the servo tracks 44 and 46, a PES can be generated to identify the lateral positioning error of the read head with respect to the data track. Although the PES calculation requires only a single servo pattern, data from multiple servo patterns in the servo track can be combined to improve the accuracy of the PES. The servo patterns in the servo track 44 are substantially the same as each other, and the servo patterns in the servo track 46 are also substantially the same. This means that the same PES formula can be used for each servo pattern in the servo track.

FIG. 5 is a conceptual diagram of an exemplary data storage system 78 using the magnetic storage tape 92. The magnetic tape 92 is an example of the magnetic tapes 10, 32, and 40 described herein and may be substantially similar. As shown in FIG. 5, the magnetic storage device 84 can be used with the configuration of the magnetic tape 92, for example, a magnetic recording medium. The magnetic storage device 84 can include a magnetic tape drive, a magnetic tape cartridge drive, and the like. The magnetic tape 92 can be spooled on one or more spools 94A and 94B (collectively referred to as "spool 94"). The spool 94 may be housed in a cartridge, but the disclosure is not limited in that respect.

The magnetic tape 92 can include a vertical magnetic tape and can include a substrate, a base layer, a magnetic layer, and other layers. The read / write head 86 is a magnetic head and can be arranged so as to detect a magnetic transition, that is, a change in the magnetic orientation of the magnetic particles in the magnetic layer on the tape 94. Although the magnetic transition can be detected as a change in the read signal from the change in magnetic orientation, the read / write head 86 can also detect the magnetic orientation of the magnetic layer based on the detected signal in some examples. The controller 88 controls the positioning of the read / write head 86 and the running of the tape 92 by rotating the spools 94A and / or 94B to accurately position the read / write head 86 with respect to the tape 92. As described with reference to FIG. 4, the controller 88 can utilize the detected servo patterns in one or more servo tracks to position the read / write head 86 on the data track of the magnetic tape 92. .. The signal processor 90 interprets the detected magnetic transition.

The magnetic storage device 84 of FIG. 5 may also be coupled to the computer 80 via the interface 82. The computer 80 is, for example, a PC, a computer, a computer workstation, a handheld data terminal, a palm computer, a mobile phone, a digital paper, a digital television, a wireless device, a personal digital assistant, a laptop computer, a desktop computer, a digital camera, a digital recording device. Can include a central processing unit for any of a variety of computer equipment, including. The computer 80 can interpret the output signal from the signal processor 90 as data and perform additional calculations and processing so that the data stored on the magnetic tape 92 can be used by the computer 80 and / or the user. The information stored on the magnetic tape 92 from the computer 80 is often a backup copy of the information stored in another storage device (eg, a hard drive) of the computer 80.

In addition to the device shown in FIG. 5, the magnetic tape 92 can be configured to work with other types of storage devices. For example, magnetic tape 92 is to be used for high density recording applications such as use in T10000, LT03, LT04, LT05, Quantum S5, Quantum S6, 3592, or other well-designed magnetic recording tape drives. Can be configured.

6A and 6B are a conceptual diagram of an exemplary bias in a substantially longitudinal magnetic orientation with servo marks and a graph of the corresponding read signal 136. The magnetic tapes 100 and 116 are, for example, an example of the magnetic tape 10. As shown in FIG. 6A, sequential magnetic heads 110 and 112 located on opposite sides of the magnetic tape 100 are used to generate a substantially longitudinal bias in the magnetic tape 100. The magnetic tape 100 includes a base material 102 and a magnetic layer 103 having a bias formed on the magnetic layer 103. When the magnetic tape 100 is run in the direction of arrow 114 and passed in the vicinity of the magnetic heads 110 and 112, the magnetic layer 103 is substantially longitudinally magnetically oriented (or substantially longitudinally remanently magnetized). The bias to have is formed.

All arrows showing the magnetic orientation in FIG. 6A are limited to the vertical and longitudinal components. That is, the arrow in the vertical component portion 106 only indicates that the vertical component of the magnetic orientation in the magnetic layer 103 is directed away from the substrate 102, for example, at 0 degrees. Therefore, the arrow of the longitudinal component portion 104 indicates that the longitudinal component of the magnetic orientation in the magnetic layer 103 is oriented in the same direction as the arrow 114, eg, 90 degrees. Thus, the overall magnetic orientation within the magnetic layer 103 between the heads 110 and 112 is, for example, within the directional octet I or II. If the magnitude of the vertical component is greater than the magnitude of the longitudinal component, the overall magnetic orientation may be within the directional octet I. Conversely, if the magnitude of the longitudinal component is greater than the magnitude of the vertical component, the overall magnetic orientation may be within the directional octet II. Here, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation or remanent magnetization of the magnetic tape.

First, the magnetic tape 100 passes through the head 110 generating the magnetic field 111. The arrows in the magnetic field 111 are shown with vertical and longitudinal components to indicate the general direction of the magnetic field 111. The first portion of the magnetic field 111 applied to the magnetic tape 100 is directed towards the substrate 102. The middle portion of the magnetic field 111 is directed along the magnetic tape 100 in the direction of arrow 114. The last portion of the magnetic field 111 applied to the magnetic tape 100 is directed away from the substrate 102. Since this last portion of the magnetic field 111 has the last effect on the magnetic layer 103, the vertical component portion 106 indicates that the vertical component of the generated magnetic orientation is oriented away from the substrate 102. Further, the magnetic layer 103 contains a longitudinal component generated by an intermediate portion of the magnetic field 111, which is shown as the longitudinal component portion 104, and remains in magnetic orientation even after the magnetic tape 100 has passed through the head 110.

Second, the magnetic tape 100 then passes through a head 112 that generates a magnetic field 113. The arrows in the magnetic field 113 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 113. A magnetic field 113 is applied to the opposite side of the magnetic field 111 of the magnetic tape 100, but the magnetic fields 111 and 113 are directed along the magnetic tape 100 toward the arrow 114 in the same general direction. The first portion of the magnetic field 113 applied to the magnetic tape 100 is directed towards the substrate 102. The middle portion of the magnetic field 113 is directed along the magnetic tape 100 in the direction of arrow 114. The last portion of the magnetic field 113 applied to the magnetic tape 100 is directed away from the substrate 102. Since this last portion of the magnetic field 113 also has the last effect on the magnetic layer 103, the vertical component portion 108 without arrows indicates that the vertical component is substantially zero. The last portion of the magnetic field 113 can be adjusted to be opposite to the vertical component remaining in the magnetic layer 103 after the magnetic field 111. In other words, the overall magnetic orientation of the magnetic layer 103 after passing through the magnetic field 113 is substantially longitudinal in the traveling direction of the tape 100, for example about 90 degrees. Therefore, the bias (eg, magnetic orientation or residual magnetization) of the magnetic tape 100 after passing through the heads 110 and 112 is substantially longitudinal.

In some examples, the positions of the magnetic heads 110 and 112 can be switched such that the magnetic tape 100 passes near the magnetic head 112 in front of the magnetic head 110. In another example, the longitudinal bias in the opposite direction can be created by switching between the directions of the magnetic fields 111 and 113, or by running the magnetic tape 100 in the opposite direction of the arrow 114. The magnetic fields 111 and 113 are simplified with only vertical or longitudinal components to show the effect on the magnetic layer 103. In practice, the magnetic fields 111 and 113 can generally have an arch or horseshoe shape produced by the magnetic heads 110 and 112. Thus, the magnetic fields 111 and 113 can, in some examples, have both vertical and longitudinal component orientations through most of the magnetic field.

As shown in FIG. 6B, the servo head 134 applies a magnetic field 135 to the magnetic tape 100 to generate a magnetic tape 116 having one or more servo marks. The servo head 134 (an example of a magnetic head) is located on the magnetic layer side of the magnetic tape 116, but in another example, the servo head 134 may be arranged on the base material 102 side. Prior to the magnetic tape 116 passing near the servo head 134, the magnetic tape 116 is substantially free of vertical components as indicated by the vertical component portion 124, as indicated by the longitudinal component portion 118. Includes magnetic orientation with only longitudinal components. When the servo head 134 applies the magnetic field 135 to the magnetic layer 103, the magnetic field 135 changes the magnetic orientation of some magnetic particles using the bias created earlier from FIG. 6A.

When a magnetic field 135 is applied to the magnetic layer 103 of the magnetic tape 116, the magnetic orientation or remanent magnetization changes in a particular region of the magnetic tape 116. The leading edge of the magnetic field 135, i.e., the portion of the magnetic field 135 directed away from the substrate 102, directs the magnetic particles away from the substrate 102, producing a vertical component portion 126. The trailing edge of the magnetic field 135, i.e., the portion of the magnetic field 135 directed away from the substrate 102, directs the magnetic particles away from the substrate 102, producing a vertical component portion 130. Since the middle portion of the magnetic field 135 has a substantially longitudinal direction, the vertical component portion 128 remains substantially zero.

An intermediate portion of the magnetic field 135 having a substantially longitudinal direction opposite to the direction of tape travel indicated by arrow 114 redirects the longitudinal component as indicated by the longitudinal component portion 120. That is, the overall magnetic orientation of the written servo mark is about 270 degrees, and the overall magnetic orientation of the remaining bias in the unwritten region is about 90 degrees. For example, since the magnetic field 135 was not applied to this region of the magnetic tape 116, the longitudinal component portion 122 does not change at about 90 degrees and the vertical component portion 132 remains unchanged at near zero magnitude. Therefore, the servo mark and the servo pattern including the servo mark have a magnetic orientation substantially opposite to the magnetic orientation of the bias on the magnetic tape 116. The remaining bias is also referred to as the non-patterned region of the servo track. In another example, the magnetic field 135 may be applied to the magnetic tape 116 for a longer period of time, eg, a longer pulse, so that the vertical component portions 126 and 128 and the longitudinal component portion 120 are more A long length of magnetic tape 116 can be covered.

FIG. 6B also shows an example of a read signal 136 of the magnetic orientation of the magnetic tape 116 detected by the read head. The amplitude 138 of the readout signal 136 fluctuates as the magnetic orientation of the particles in the magnetic layer 103 changes over the length of the magnetic tape 116. Pulses 140 and 142 indicate a change in magnetic orientation between the servo mark and the bias of the magnetic tape 116. In general, a larger amplitude between the pulses 140 and 142 is desirable to produce a higher signal-to-noise ratio than would otherwise be achieved if the difference between the pulses is small.

7A and 7B are conceptual diagrams of exemplary bias and servo patterns in vertical magnetic orientation and graphs of the corresponding readout signal 180. The magnetic tapes 146 and 164 are, for example, an example of the magnetic tape 10. 7A and 7B are similar to FIGS. 6A and 6B, except that a vertical bias is generated instead of a longitudinal bias. As shown in FIG. 7A, the sequential heads 160 and 162 having magnetic fields 161 and 163 in opposite directions are arranged on opposite sides of the tape 146 and generate a substantially vertical bias on the tape 146. The magnetic tape 146 includes a base material 148 and a magnetic layer 149 having a bias formed on the magnetic layer 149. When the tape 146 is run in the direction of arrow 114 so as to pass near the magnetic heads 160 and 162, a bias with vertical magnetic orientation is generated in the magnetic layer 149.

Similar to FIGS. 6A and 6B, all arrows indicating the magnetic orientation of FIG. 7A are limited to the vertical and longitudinal components. That is, the arrow in the vertical component portion 154 only indicates that the vertical component of the magnetic orientation in the magnetic layer 149 is oriented away from the substrate 148, for example 0 degrees. Therefore, the arrow of the longitudinal component portion 150 indicates that the longitudinal component of the magnetic orientation in the magnetic layer 149 is oriented in the same direction as the arrow 114, eg, 90 degrees. Thus, the overall magnetic orientation within the magnetic layer 149 between the heads 160 and 162 is, for example, within the eighth circle I or II. If the magnitude of the vertical component is greater than the magnitude of the longitudinal component, the overall magnetic orientation may be within the directional octet I. Conversely, if the magnitude of the longitudinal component is greater than the magnitude of the vertical component, the overall magnetic orientation may be within the directional octet II. Here, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation or remanent magnetization of the magnetic tape.

First, the magnetic tape 146 passes through the head 160 generating the magnetic field 161. The arrows in the magnetic field 161 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 161. The first portion of the magnetic field 161 applied to the magnetic tape 146 is directed in the direction of the substrate 148. The middle portion of the magnetic field 161 is directed along the magnetic tape 146 in the direction of arrow 114. The last portion of the magnetic field 160 applied to the magnetic tape 146 is directed away from the substrate 148. Since this last portion of the magnetic field 161 has the last effect on the magnetic layer 149, the vertical component portion 154 indicates that the vertical component of the generated magnetic orientation is oriented away from the substrate 148. Further, the magnetic layer 149 contains a longitudinal component generated by an intermediate portion of the magnetic field 161 shown as the longitudinal component portion 150 and remains in magnetic orientation even after the magnetic tape 146 has passed through the head 160.

Second, the magnetic tape 146 then passes through a head 162 that generates a magnetic field 163. The arrows in the magnetic field 163 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 163. The magnetic field 163 is applied to the opposite side of the magnetic tape 146 to the magnetic field 161 and the magnetic field 163 is generally directed along the magnetic tape 146 in the direction opposite to the magnetic field 161 and in the direction opposite to the arrow 114. The first portion of the magnetic field 163 applied to the tape 146 is directed away from the substrate 148 and produces a vertical component towards the substrate 148 as indicated by the vertical portion 156. The middle portion of the magnetic field 163 is directed along the magnetic tape 146 in the direction opposite to the arrow 114. The opposite magnetic field can be adjusted to reduce any longitudinal component to zero, which is not indicated by the arrow in the longitudinal component portion 152. The last portion of the magnetic field 163 applied to the magnetic tape 146 is directed towards the substrate 148. Since this last portion of the magnetic field 163 also has a final effect on the magnetic layer 149, the vertical component portion 158 is directed to the substrate 148 to indicate that the vertical component is directed away from the substrate 148. Includes an arrow pointing away from. The last portion of the magnetic field 163 inverted the vertical component generated in the magnetic layer 149 from the first portion or leading edge of the magnetic field 163. In other words, the overall magnetic orientation or remanent magnetization of the magnetic layer 149 after passing through the magnetic field 163 is substantially perpendicular to the traveling direction of the tape 146, eg, about 0 degrees.

Thus, the bias (eg, magnetic orientation or remanent magnetization) of the magnetic tape 146 after passing through the heads 160 and 162 is substantially perpendicular or oriented to one of the octagons I or VIII. In some examples, a substantially vertical orientation indicates that each longitudinal component of the plurality of magnetic particles is substantially smaller than the respective vertical component of the plurality of magnetic particles. In another example, a substantially vertical orientation indicates that the longitudinal component of each of the plurality of magnetic particles is substantially zero.

As shown in the example of the magnetic tape 164, the magnetic orientation 174 of at least a part of the magnetic particles in the servo pattern is substantially oriented toward the substrate, and the magnetic orientation of the magnetic particles in the non-pattern region of the magnetic bias. 176 is oriented substantially away from the substrate 148. Alternatively, the magnetic orientation of at least a portion of the magnetic particles in the servo pattern may be substantially oriented away from the substrate 148, and the magnetic orientation of the magnetic particles in the non-patterned region of the magnetic bias is substantial. May be oriented in the direction of the substrate 148. In any example, the magnetic orientation of most of the magnetic particles in the magnetic tape 164 may be substantially perpendicular to the substrate 148.

As shown in FIG. 7A, the direction of the residual magnetization, eg, the bias or direction of the magnetic orientation 158, is substantially perpendicular to the substrate 148. Due to being substantially perpendicular to the substrate 148, the magnetic orientation 158 can form an angle of at least 45 degrees with the substrate 148. In another example, the magnetic orientation 158 can form an angle of at least 60 ° with the substrate. However, any angle formed above 45 degrees can be considered to be substantially vertical.

Alternatively, the residual magnetization of the magnetic orientation 158 can have a vertical component perpendicular to the substrate 148 and a longitudinal component parallel to the substrate. The longitudinal component may be less than 50% larger than the vertical component, or, in other examples, less than 25% or less than 10% than the vertical component.

In some examples, the positions of the magnetic heads 160 and 162 can be switched so that the magnetic tape 146 passes near the magnetic head 162 in front of the magnetic head 160. In another example, a vertical bias in the opposite direction (eg, towards the substrate 148) switches both directions of the magnetic fields 161 and 163 so that the substrate 148 approaches the head 160 instead of the head 162. It can be produced by this or by inverting the magnetic tape 146.

As shown in FIG. 7B, the servo head 178 applies a magnetic field 179 to the magnetic tape 146 to generate a magnetic tape 164 having one or more servo marks. The servo head 178 and the magnetic head are located on the magnetic layer side of the magnetic tape 164, but in another example, the servo head 178 may be arranged on the base material 148 side. Before the tape 164 passes near the servo head 178, the tape 164 is substantially free of longitudinal components as indicated by the longitudinal component portion 166, as indicated by the vertical component portion 172. Includes magnetic orientation with only vertical components. When the servo head 178 applies a magnetic field 179 to the magnetic layer 149, the magnetic field 179 changes the magnetic orientation of some magnetic particles using the bias created earlier from FIG. 7A.

When a magnetic field 179 is applied to the magnetic layer 149 of the magnetic tape 164, the magnetic orientation changes in a specific region of the magnetic tape 164. This occurs because the pattern of the magnetic field 179 may contain different orientations at different positions of the magnetic head 178. The leading edge of the magnetic field 179, i.e., the portion of the magnetic field 179 directed away from the substrate 148, directs the magnetic particles away from the substrate 102, producing a vertical component portion 126. However, the trailing edge of the magnetic field 179, that is, the portion of the magnetic field 174 directed away from the substrate 148, directs the magnetic particles toward the substrate 148, as opposed to the vertical component portions 172 and 176. A vertical component portion 174 is generated. The middle of the magnetic field 179 has a substantially longitudinal direction that produces a longitudinal component opposite the arrow 114 as indicated by the longitudinal component portion 168.

The trailing edge of the magnetic field 179, which has a direction substantially perpendicular to the substrate 148, redirects the vertical component as indicated by the vertical component portion 174. That is, the overall remanent magnetization of the written servo mark includes an orientation of about 180 degrees, and the overall magnetic orientation of the remaining bias in the unwritten region is about 0 degrees. For example, since the magnetic field 179 was not applied to this region of the magnetic tape 164, the vertical component portion 172 does not change at about 0 degrees and the longitudinal component portion 170 remains unchanged at a magnitude of nearly zero. Therefore, the servo mark and the servo pattern including the servo mark have a magnetic orientation substantially opposite to the magnetic orientation of the bias on the magnetic tape 164. The remaining bias is also referred to as the non-patterned region of the servo track. In another example, the magnetic field 179 may be applied to the magnetic tape 164 for a longer period of time, eg, a longer pulse, so that the vertical component portion 174 and the longitudinal component portion 168 have a longer length. The magnetic tape 164 can be covered.

FIG. 7B also shows a read signal 180 of the magnetic orientation of the magnetic tape 164 detected by the read head. The amplitude 182 of the readout signal 180 varies as the magnetic orientation of the particles in the magnetic layer 149 changes over the length of the magnetic tape 164. Pulses 184 and 186 indicate changes in magnetic orientation between the servo marks and the bias of the magnetic tape 164. In general, a larger amplitude between the pulses 184 and 186 is desirable to produce a higher signal-to-noise ratio than would otherwise be achieved if the difference between the pulses is small.

FIG. 8 is a diagram of various magnetic orientations of bias that can be formed on a portion of the magnetic tape. As shown in FIG. 8, the magnetic tapes 210A, 218A, 226A, and 234A are magnetically biased by the residual magnetization generated by one of the directional octets I, IV, V and VIII described in FIG. 2A. The non-zero vertical and longitudinal component values of are shown. The residual magnetization of the octets I, IV, V, and VIII can have a vertical component that is substantially larger than the corresponding longitudinal component, but if a larger longitudinal component is desired, the octet Residual magnetization in circles II, III, VI and VII can be generated. The magnetic tapes 210B, 218B, 226B and 234B indicate the overall magnetic orientation or remanent magnetization of the plurality of magnetic particles in the magnetic layer of the magnetic tape. Magnetic tapes 242A and 242B use alternating current to exhibit random magnetic orientation or minimal residual magnetization of magnetic particles. The magnetic tapes 210A, 210B, 218A, 218B, 226A, 226B, 234A, 234B, 242A, 242B are all similar to the magnetic tape 10 and are driven to the left or 90 degrees as described in FIG. 2A. It is stated that. Any of these biases may be formed on a substantial portion of the magnetic tape, such as the magnetic tape, prior to writing one or more servo patterns onto the bias.

The magnetic tape 210A includes a base material 212 formed on a magnetic layer having a residual magnetization in the directional octagonal circle I. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by the longitudinal component portion 214 and the vertical component portion 216. The longitudinal component portion 214 provides an arrow indicating that the longitudinal component is in the 90 degree direction. The vertical component portion 216 provides an arrow indicating that the vertical component is oriented away from the substrate 212 or in the 0 degree direction. Therefore, the magnetic tape 210B provides a magnetic orientation 254 that includes an arrow indicating that the magnetic orientation 254 is a directional octet I.

The magnetic tape 218A includes a base material 220 formed on a magnetic layer having a residual magnetization in the directional octagonal circle V. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by the longitudinal component portion 222 and the vertical component portion 224. The longitudinal component portion 222 provides an arrow indicating that the longitudinal component is in the 270 degree direction. The vertical component portion 224 provides an arrow indicating that the vertical component is oriented towards the substrate 220 or oriented 180 degrees. Therefore, the magnetic tape 218B provides a magnetic orientation 260 that includes an arrow indicating that the magnetic orientation 260 is a directional octet V.

The magnetic tape 226A contains a substrate 228 formed on a magnetic layer having a residual magnetization in the directional octet VIII. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by the longitudinal component portion 230 and the vertical component portion 232. The longitudinal component portion 230 provides an arrow indicating that the longitudinal component is in the 270 degree direction. The vertical component portion 232 provides an arrow indicating that the vertical component is oriented away from the substrate 228 or in the 0 degree direction. Therefore, the magnetic tape 226B provides a magnetic orientation 266 that includes an arrow indicating that the magnetic orientation 266 is a directional octagonal circle VIII.

The magnetic tape 224A contains a substrate 236 formed on a magnetic layer having a remanent magnetization in the directional octet IV. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by the longitudinal component portion 238 and the vertical component portion 240. The longitudinal component portion 238 provides an arrow indicating that the longitudinal component is in the 90 degree direction. The vertical component portion 240 provides an arrow indicating that the vertical component is oriented towards the substrate 236 or 180 degrees. Therefore, the magnetic tape 234B provides a magnetic orientation 272 that includes an arrow indicating that the magnetic orientation 272 is a directional octagon IV.

Magnetic tapes 242A and 242B use alternating current to exhibit random magnetic orientation of magnetic particles or virtually zero residual magnetization. The magnetic tape 242A comprises a substrate 244 formed on a magnetic layer having a randomized magnetic orientation with two or more directional octets. The longitudinal component portion 246 and the vertical component 248 are shown as shaded regions because there is no overall remanent magnetization of the magnetic layer. Therefore, the magnetic tape 242B provides a magnetic orientation 278 that includes an arrow indicating the random orientation of the magnetic particles in the magnetic layer. Each arrow may not be representative of an individual magnetic particle, but each arrow indicates the magnetic orientation of at least one magnetic particle in that region of the tape 242B. Unlike the other magnetic tapes of FIG. 8, the magnetic orientation of one or more particles can have a non-zero longitudinal or vertical component value. The randomized magnetic orientation biases of the magnetic tapes 242A and 242B may be used in some examples to write the servo pattern to any desired directional octet.

As shown in FIG. 8, the magnetic tapes 210B, 218B, 226B, and 234B have residual magnetization in a direction substantially perpendicular to the substrate. That is, the remanent magnetization is directed to one of the directional eight-quarter circles I, IV, V or VIII. Thus, the vertical component of the residual magnetization in one of the directional octets I, IV, V or VIII may be larger than the corresponding longitudinal component. In some examples, the vertical component may be 75%, or 90%, more than the longitudinal component. Typically, the magnetic bias can be in the octet on the opposite side of the octet of the residual magnetization of the servo mark. In this way, for example, the magnetic tape can include a servo mark having a magnetic bias in the directional octet I and a remanent magnetization in the directional octet IV or V.

In another example, the magnetic tape can utilize a substantially longitudinal remanent magnetization in one direction of the directional octet II, III, VI or VII. In these directional octets, the longitudinal component may be 75% or 90% larger than the vertical component. In this way, the residual magnetization of the bias mark and servo mark is substantially longitudinal. In one example, the magnetic tape can have a bias with an orientation in the directional octet II and a servo mark with a residual magnetization in the opposite directional octet VI. Although these substantially longitudinal magnetizations are conceivable, only residual magnetization having substantially vertical orientations is provided as an example of FIGS. 9A-13B.

9A and 9B show a conceptual diagram of an exemplary magnetic medium containing a magnetic bias of a directional octet I with remanent magnetization, along with a graph of the corresponding readout signal. As shown in FIG. 9A, the magnetic tape 280 is an example of the magnetic tape 10. As shown in FIG. 9A, the magnetic tape 280 contains one or more servo patterns written to the magnetic bias within the directional octet I of the magnetic tape 210A of FIG. One or more servo patterns are written with the remanent magnetization of the directional octet IV.

A magnetic head 290, such as a servo write head, is used to form a servo pattern, i.e. some servo marks, on a magnetic bias preformed on the magnetic tape 280. When the magnetic tape 280 is run in the direction of the arrow 292 so as to pass near the magnetic head 290, a servo mark is formed in the magnetic layer of the magnetic tape 280.

All arrows showing the magnetic orientation in FIG. 9A are limited to the vertical and longitudinal components. That is, the arrow in the vertical component portion 284 only indicates that the vertical component of the magnetic orientation in the magnetic layer is oriented away from the substrate, for example 90 degrees. Therefore, the arrow of the longitudinal component portion 282 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is directed in the same direction as the arrow 292, eg, 0 degrees. The overall residual magnetization in the magnetic layer is the directional octet I in the magnetic bias and the directional octet IV in the servo pattern. Here, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation of the magnetic tape and magnetic field. However, FIG. 9B shows the overall magnetic orientation without the longitudinal and vertical components.

In order to form a servo pattern on the magnetic tape 280, the magnetic tape 280 is driven beyond the magnetic head 290 generating the magnetic field 291. The arrows in the magnetic field 291 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 291. Generally, the magnetic field 291 is in the same direction as the magnetic field used to generate the magnetic bias. The first portion of the magnetic field 291 applied to the magnetic tape 280 is directed in the direction of the magnetic tape 280. The middle portion of the magnetic field 291 is directed along the magnetic tape 280 in the direction of arrow 292. The last portion of the magnetic field 291 applied to the magnetic tape 280 is directed away from the substrate. Since this last portion of the magnetic field 291 has the last effect on the tape 280, the vertical component portion 284 indicates that the vertical component of the magnetic bias is maintained in the directional octet I.

When a magnetic field 291 is applied to the magnetic tape 280, the leading edge of the magnetic field 291 switches the vertical component of the magnetic particles as shown in the vertical component portion 286. In this way, the vertical component portion 286 defines different magnetic orientations of the servo marks of the directional octet IV. The vertical component portion 288 remains on the magnetic tape as part of the previously formed magnetic bias.

FIG. 9A also shows an example of a read signal 294 of the magnetic orientation of the magnetic tape 280 detected by the read head. The amplitude 296 of the readout signal 294 varies as the magnetic orientation of the particles in the magnetic layer changes between the magnetic bias and the servo pattern over the length of the tape 280. Pulse 298, for example a unipolar pulse, indicates a change in magnetic orientation between the directional octet I of the magnetic bias and the directional octet IV of the servo mark.

As shown in FIG. 9B, the overall residual magnetization of the tape 280 is illustrated instead of using the longitudinal and vertical components provided in FIG. 9A. That is, the overall remanent magnetization can be similar to the magnetic field lines or patterns of the magnetic field. The magnetic tape 280 is shown in the magnetic orientation shown in the magnetic tape 210B of FIG. The magnetic head 290 generates a magnetic field 307 applied to the magnetic tape 280 as the magnetic tape 280 is driven over the magnetic head 290 in the direction of arrow 292. The magnetic head 290 can apply a magnetic field 307 from the same side of the magnetic tape 280 as the magnetic field used to generate the magnetic bias. Generally, the magnetic field 307 can be described as having an arch shape or a horseshoe shape.

The leading edge of the magnetic field 307 forms a magnetic orientation 302 in the directional octet IV, and the trailing edge of the magnetic field 307 generally restores the bias magnetic orientation 300 to the directional octet I. The magnetic orientation 304 remains the directional octet I because that portion of the magnetic tape 280 is not affected by the magnetic field 307. Therefore, the servo mark includes the magnetic orientation of the directional octet IV, which is generally opposite to the directional octet I of the magnetic bias. Further, the servo mark shown in FIG. 9B can be described as having a first magnetic orientation of the directional octet IV and a second magnetic orientation of the directional octet I (eg, servo). The mark can include a magnetic orientation or remanent magnetization in substantially the same direction as the bias in the non-patterned region. As expected, the read signal 308 is similar to the read signal 294 in FIG. 9A. 294 includes an amplitude 310 and a pulse 312 (eg, a unipolar pulse) corresponding to a change in the directional octet between the magnetic bias and the servo mark.

According to FIGS. 9A and 9B, the magnetic tape 280 comprises a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. The servo track of the magnetic layer also includes servo patterned and non-patterned areas. The servo pattern includes a plurality of servo marks having a pattern residual magnetization of the directional octagon IV in contact with the vertical plane 23 orthogonal to the substrate. Non-patterned regions, such as magnetic bias, include non-patterned remanent magnetization within the directional octet I, which also touches the vertical plane 23. The octets I and IV are on the same side of the vertical plane 23 and the octets I and IV are on the opposite side of the longitudinal plane 21. That is, the vertical components of the octets I and IV are in opposite directions, and the longitudinal components of the octets I and IV are in the same direction.

The remanent magnetization in the octets I and IV may be configured to generate a read signal 308 (eg, a servo signal) with a read head to identify each of the servo marks. If the remanent magnetization of the magnetic tape 280 has a vertical component opposite to the vertical component of the bias magnetization and the remanent magnetization matches or has a longitudinal component in the same direction as the longitudinal component of the bias magnetization, the signal 308. Can include an amplitude 310 (eg, a waveform) having a substantially unipolar pulse 312.

10A and 10B show a conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet V, along with a graph of the corresponding readout signal. As shown in FIG. 10A, the magnetic tape 314 is an example of the magnetic tape 10. As shown in FIG. 10A, the magnetic tape 314 contains one or more servo patterns written to the magnetic bias within the directional octet V of the magnetic tape 218A of FIG. One or more servo patterns are written in the directional octets I and IV, which are generally opposite to the directional octets V of the magnetic bias.

A magnetic head 328, such as a servo write head, is used to form a servo pattern, i.e. some servo marks, on a magnetic bias preformed on the magnetic tape 314. When the magnetic tape 314 is driven or driven in the direction of arrow 292 so as to pass near the magnetic head 328, a servo mark is formed in the magnetic layer of the magnetic tape 314.

Similar to FIG. 9A, all arrows indicating the magnetic orientation of FIG. 10A are limited to the vertical and longitudinal components. The arrow in the vertical component portion 322 only indicates that the vertical component of the magnetic orientation in the magnetic layer is oriented towards the substrate, eg, 270 degrees. Therefore, the arrow of the longitudinal component portion 316 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is directed in the opposite direction of the arrow 292, for example 180 degrees. Therefore, the overall residual magnetization in the magnetic layer is the directional octet V in the magnetic bias and the directional octet I in the servo pattern. Here, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation of the magnetic tape and magnetic field. However, FIG. 10B shows the overall magnetic orientation without the longitudinal and vertical components.

In order to form a servo pattern on the magnetic tape 314, the magnetic tape 314 is driven beyond the magnetic head 328 generating the magnetic field 329. The arrows in the magnetic field 329 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 329. The magnetic field 329 may be generated in the direction opposite to the magnetic field used to generate the magnetic bias of the tape 218A. The first portion of the magnetic field 329 applied to the magnetic tape 314 is directed in the direction of the magnetic tape 314. The middle portion of the magnetic field 329 is directed along the magnetic tape 280 in the direction of arrow 292. The last portion of the magnetic field 329 applied to the magnetic tape 314 is directed away from the substrate. Since this last part of the magnetic field 329 has the last effect on the magnetic tape 314, the vertical component 324 changes the vertical component of the magnetic orientation so that the overall remanent magnetization is the directional octet I. Show that you do.

When the magnetic field 329 is applied to the magnetic tape 314, the leading edge of the magnetic field 329 maintains the vertical component portion 326. However, the intermediate portion of the magnetic field 329 switches the longitudinal component of the portion 318 from the opposite arrow 292 of the longitudinal component portion 320 to the arrow 292 of the longitudinal component portion 318. In this way, the vertical component portion 324 and the longitudinal component portion 318 define different residual magnetizations of the servo marks in both the directional octets IV and I. The vertical component portion 322 and the longitudinal component portion 316 remain on the tape 314 as part of the previously generated magnetic bias.

FIG. 10A also shows an example of a read signal 330 of the residual magnetization of the magnetic tape 314 detected by the read head. The amplitude 322 of the readout signal 330 varies as the magnetic orientation of the particles in the magnetic layer changes between the magnetic bias and the servo pattern over the length of the tape 314. The pulse 334 provides the maximum change in amplitude from the change in magnetic orientation between the directional octet V of the magnetic bias and the directional octet I of the servo mark containing the vertical component portion 324. A pulse 336 showing a change from the longitudinal component portion 318 to the longitudinal component portion 320, eg, a change in the directional octets V and IV, provides a smaller amplitude change than the amplitude change of the pulse 334. Both pulses 334 and 336 may be described as bipolar pulses.

As shown in FIG. 10B, the overall residual magnetization of the magnetic tape 314 is illustrated instead of using the longitudinal and vertical components provided in FIG. 10A. The magnetic tape 314 is shown in the magnetic orientation shown in the magnetic tape 218B of FIG. The magnetic head 328 generates a magnetic field 347 applied to the magnetic tape 314 as the magnetic tape 314 is driven over the magnetic head 328 in the direction of arrow 292. The magnetic head 328 can apply a magnetic field 347 from the same side of the magnetic tape 314 as the magnetic field used to generate the magnetic bias. Generally, the magnetic field 347 can be described as having an arch shape or a horseshoe shape.

The leading edge of the magnetic field 347 generates a magnetic orientation 342 in the directional octet IV, and the trailing edge of the magnetic field 347 causes a magnetic orientation 340 in the directional octet I. Therefore, the entire servo mark formed by the magnetic field has a residual magnetization with an octagonal circle different from that of the magnetic bias. Since the portion of the magnetic tape 314 is not affected by the magnetic field 347, the magnetic orientations 338 and 344 remain the directional octet V. Therefore, the servo mark includes a magnetic orientation in the directional octet I and a magnetic orientation in the directional octet IV opposite to the directional octet (ie, directional octet V) of the magnetic bias. Further, the servo mark shown in FIG. 10B is a third directional octet different from the first magnetic orientation of the directional octet I and the directional octet V in the biased or non-patterned region, for example. It may be described as having a second magnetic orientation of the directional octet IV. Therefore, the servo mark can include magnetic orientation or remanent magnetization in two or more directional octets. As expected, the read signal 348 is similar to the read signal 330 in FIG. 10A. The readout signal 348 includes amplitudes 350 and pulses 352 and 354 (both including bipolar pulses) corresponding to the change in directional octet between the magnetic bias and the servo mark.

According to FIGS. 10A and 10B, the magnetic tape 314 includes a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. The servo track of the magnetic layer also includes servo patterned and non-patterned areas. The servo pattern includes a plurality of servo marks having a pattern residual magnetization of a directional octagonal circle I tangent to the vertical plane 23 orthogonal to the substrate. Non-patterned regions, such as magnetic bias, include non-patterned remanent magnetization within the directional octet V, which also touches the vertical plane 23. The octets I and V are on the opposite side of the vertical plane 23 and the octets I and IV are on the opposite side of the longitudinal plane 21. That is, the vertical components of the octets I and V are in opposite directions, and the longitudinal components of the octets I and V are in opposite directions.

The remanent magnetization in the octets I and V may be configured to generate a read signal 348 (eg, a servo signal) with a read head to identify each of the servo marks. If the residual magnetization of the tape 314 has a vertical component opposite to the vertical component of the bias magnetization and the residual magnetization has a longitudinal component that is also opposite to the longitudinal component of the bias magnetization, then the signal 348 is substantial. Can include an amplitude 350 (eg, a waveform) having unipolar pulses 352 and 354. The stronger pulse 352 has a vertical component opposite the vertical component of the bias magnetization (eg, the vertical component portions 322 and 324) and a longitudinal component opposite the longitudinal component of the bias magnetization (eg, the longitudinal component portion). It may correspond to the first part of the residual magnetization having 316 and 318). The weaker pulse 354 has a vertical component that matches the vertical component of the bias magnetization (eg, the vertical component portion 326) and a longitudinal component opposite the longitudinal component of the bias magnetization (eg, the longitudinal component portion 318 and). It may correspond to the second part of the residual magnetization having 320) and. Both pulses 352 and 354 may be described as bipolar pulses.

11A and 11B show a conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet VIII, along with a graph of the corresponding readout signal. As shown in FIG. 11A, the magnetic tape 356 is an example of the magnetic tape 10. As shown in FIG. 11A, the magnetic tape 356 includes one or more servo patterns written to the magnetic bias within the directional octet VIII of the magnetic tape 226A of FIG. One or more servo patterns are written in the directional octets I and IV, which are generally opposite to the directional octets VIII of the magnetic bias.

A magnetic head 372, such as a servo write head, is used to form a servo pattern, i.e. some servo marks, on a magnetic bias preformed on the magnetic tape 356. When the magnetic tape 356 is driven or driven in the direction of arrow 292 so as to pass near the magnetic head 372, a servo mark is formed in the magnetic layer of the magnetic tape 356.

Similar to FIG. 9A, in FIG. 11A, all arrows indicating residual magnetization are limited to the vertical and longitudinal components. The arrow in the vertical component portion 364 only indicates that the vertical component of the magnetic orientation in the magnetic layer is oriented away from the substrate, eg, 90 degrees. Therefore, the arrow of the longitudinal component portion 358 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is directed in the opposite direction of the arrow 292, for example 180 degrees. Therefore, the overall magnetic orientation in the magnetic layer is the directional octets VIII in the magnetic bias and the directional octets I and IV in the servo pattern. Here, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the residual magnetization of the magnetic tape and magnetic field. However, FIG. 11B shows the overall magnetic orientation without the longitudinal and vertical components.

In order to form a servo pattern on the magnetic tape 356, the magnetic tape 356 is driven over a magnetic head 372 that generates a magnetic field 373. The arrows in the magnetic field 373 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 373. The magnetic field 373 may be generated in the direction opposite to the magnetic field used to generate the magnetic bias of the tape 226A. The first portion of the magnetic field 373 applied to the magnetic tape 356 is directed in the direction of the magnetic tape 356. The middle portion of the magnetic field 373 is directed along the magnetic tape 356 in the direction of arrow 292. The last portion of the magnetic field 373 applied to the magnetic tape 356 is directed away from the substrate. Since this last portion of the magnetic field 373 has the last effect on the tape 356, the vertical component portion 366 indicates that the vertical component of the magnetic orientation remains unchanged from the magnetic bias.

When the magnetic field 373 is applied to the magnetic tape 356, the leading edge of the magnetic field 373 changes the vertical component portion 368 from the vertical component portion 370 of the magnetic bias. However, the intermediate portion of the magnetic field 373 switches the longitudinal component of the portion 360 from the opposite arrow 292 of the longitudinal component portion 362 to the arrow 292 of the longitudinal component portion 360. In this way, the vertical component portion 368 and the longitudinal component portion 360 define different magnetic orientations of the servo marks in both the directional octets IV and I. The vertical component portion 364 and the longitudinal component portion 358 remain on the tape 356 as part of the previously generated magnetic bias.

FIG. 11A also shows an example of a read signal 374 of the magnetic orientation of the magnetic tape 356 detected by the read head. The amplitude 376 of the readout signal 374 varies as the magnetic orientation of the particles in the magnetic layer changes between the magnetic bias and the servo pattern over the length of the tape 356. The pulse 378 provides a change in amplitude from a change in magnetic orientation between the directional octet VIII of the magnetic bias and the generally opposite directional octet I of the servo mark containing the longitudinal component portion 360. Pulse 380 shows a larger change from longitudinal component portion 362 to longitudinal component portion 360 and vertical component portion 360 to vertical component portion 368, eg, opposite directional octets VIII and IV. Both pulses 378 and 380 may be described as bipolar pulses.

As shown in FIG. 11B, the overall residual magnetization of the magnetic tape 356 is illustrated instead of using the longitudinal and vertical components provided in FIG. 11A. The magnetic tape 356 is shown in the magnetic orientation shown in the magnetic tape 226B of FIG. The magnetic head 372 generates a magnetic field 391 applied to the magnetic tape 356 as the magnetic tape 356 is driven over the magnetic head 372 in the direction of arrow 292. The magnetic head 372 can apply the magnetic field 391 from the side of the same magnetic tape 356 as the magnetic field used to generate the magnetic bias, but the direction of the magnetic field may be switched. Generally, the magnetic field 391 can be described as having an arch shape or a horseshoe shape.

The leading edge of the magnetic field 391 creates a magnetic orientation 386 in the directional octet IV, and the trailing edge of the magnetic field 391 creates a magnetic orientation 384 in the directional octet I. Therefore, the entire servo mark formed by the magnetic field has a residual magnetization with an octagonal circle different from that of the magnetic bias. Since the portion of the tape 356 is unaffected by the magnetic field 391, the magnetic orientations 382 and 388 remain the directional octet VIII. Therefore, the servo marks are the directional octet I, which is generally opposite to the directional octet of magnetic bias (ie, directional octet VIII), and the directional octet of magnetic bias (ie, directional eight). It contains the residual magnetization of the directional octagonal circle IV, which is just the opposite of the minute circle VIII). That is, the servo mark shown in FIG. 11B has a first magnetic orientation of the directional octet IV and a third directional octet different from the biased or non-patterned directional octet VIII, eg, It may be described as having a second magnetic orientation of the directional octet I. Therefore, the servo mark can include magnetic orientation or remanent magnetization in two or more directional octets. As expected, the read signal 392 is similar to the read signal 374 of FIG. 11A. The readout signal 392 includes amplitudes 394 and pulses 396 and 398 (both including bipolar pulses) corresponding to the change in directional octet between the magnetic bias and the servo mark.

According to FIGS. 11A and 11B, the magnetic tape 356 includes a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. The servo track of the magnetic layer also includes servo patterned and non-patterned areas. The servo pattern includes a plurality of servo marks having a pattern residual magnetization of the directional octagon IV in contact with the vertical plane 23 orthogonal to the substrate. The non-patterned region, eg, magnetic bias, includes the non-patterned remanent magnetization of the directional octet VIII, which also touches the vertical plane 23. The octets IV and VIII are on the opposite side of the vertical plane 23, and the octets IV and VIII are on the opposite side of the longitudinal plane 21. That is, the vertical components of the octets IV and VIII are in opposite directions, and the longitudinal components of the octets IV and VIII are in opposite directions.

The remanent magnetization in the octets IV and VIII may be configured to generate a read signal 392 (eg, a servo signal) with a read head to identify each of the servo marks. If the residual magnetization of the tape 356 has a vertical component opposite to the vertical component of the bias magnetization and the residual magnetization has a longitudinal component that is also opposite to the longitudinal component of the bias magnetization, then the signal 392 is substantial. Can include amplitudes 394 (eg, waveforms) with unipolar pulses 396 and 398. The stronger pulse 398 has a vertical component opposite the vertical component of the bias magnetization (eg, the vertical component portions 368 and 370) and a longitudinal component opposite the longitudinal component of the bias magnetization (eg, the longitudinal component portion). It may correspond to the first part of the residual magnetization having 360 and 362). The weaker pulse 396 has a vertical component that matches the vertical component of the bias magnetization (eg, the vertical component portions 364 and 366) and a longitudinal component that is opposite to the longitudinal component of the bias magnetization (eg, the longitudinal component portion). It may correspond to the second part of the residual magnetization having 358 and 360). Both pulses 396 and 398 may be described as bipolar pulses.

12A and 12B show a conceptual diagram of an exemplary magnetic medium containing a magnetic bias of the directional octet IV, along with a graph of the corresponding readout signal. As shown in FIG. 12A, the magnetic tape 400 is an example of the magnetic tape 10. As shown in FIG. 12A, the magnetic tape 400 includes one or more servo patterns written to the magnetic bias within the directional octet IV of the magnetic tape 234A of FIG. One or more servo patterns are written in the directional octet I, which is generally opposite to the directional octet IV of the magnetic bias.

A magnetic head 410, such as a servo write head, is used to form a servo pattern, i.e. some servo marks, on a magnetic bias preformed on the magnetic tape 400. When the magnetic tape 400 is driven or driven in the direction of arrow 292 so as to pass near the magnetic head 410, a servo mark is formed in the magnetic layer of the magnetic tape 400.

Similar to FIG. 9A, all arrows indicating the magnetic orientation of the magnetic particles of FIG. 12A are limited to the vertical and longitudinal components. The arrow in the vertical component portion 404 only indicates that the vertical component of the residual magnetization in the magnetic layer is directed towards the substrate, eg, 270 degrees. Therefore, the arrow of the longitudinal component portion 402 indicates that the longitudinal component of the residual magnetization in the magnetic layer is directed in the same direction as the arrow 292, eg, 0 degrees. Therefore, the overall magnetic orientation in the magnetic layer is the directional octet IV in the magnetic bias and the directional octet I in the servo pattern. Here, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation of the magnetic tape and magnetic field. However, FIG. 12B shows the direction of the overall remanent magnetization without the longitudinal and vertical components.

In order to form a servo pattern on the magnetic tape 400, the magnetic tape 400 is driven beyond the magnetic head 410 generating the magnetic field 411. The arrows in the magnetic field 411 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 411. The magnetic field 411 may be generated in the same direction as the magnetic field used to generate the magnetic bias of the tape 234A. The first portion of the magnetic field 411 applied to the magnetic tape 400 is directed in the direction of the magnetic tape 400. The middle portion of the magnetic field 411 is directed along the magnetic tape 400 in the direction of arrow 292. The last portion of the magnetic field 411 applied to the magnetic tape 400 is directed away from the substrate. Since this last portion of the magnetic field 411 has the last effect on the tape 356, the vertical component portion 406 of the magnetic orientation is modified from the magnetic bias shown in the vertical component portions 408 and 404. Show that.

When the magnetic field 411 is applied to the magnetic tape 400, the leading edge of the magnetic field 411 changes the vertical component portion 406 from the vertical component portion 408 of the magnetic bias. The middle portion of the magnetic field 411 remains aligned with the longitudinal direction as indicated by the longitudinal component portion 402 in the same direction as the arrow 292. In this way, the vertical component portion 406 defines different magnetic orientations of the servo marks in the directional octet I adjacent to the directional octet IV of the magnetic bias.

FIG. 12A also shows an example of a read signal 412 of the magnetic orientation of the magnetic tape 400 detected by the read head. The amplitude 414 of the readout signal 412 fluctuates as the magnetic orientation of the particles in the magnetic layer changes between the magnetic bias and the servo pattern over the length of the tape 400. The pulse 416 (eg, a unipolar pulse) is from the change in residual magnetization between the directional octet IV of the magnetic bias and the generally opposite directional octet I of the servo mark containing the vertical component portion 406. Provides a change in amplitude.

As shown in FIG. 12B, the overall residual magnetization of the magnetic tape 400 is illustrated instead of using the longitudinal and vertical components provided in FIG. 12A. The magnetic tape 400 is shown in the magnetic orientation shown in the magnetic tape 234B of FIG. The magnetic head 410 generates a magnetic field 425 applied to the magnetic tape 400 as the magnetic tape 400 is driven over the magnetic head 410 in the direction of arrow 292. The magnetic head 410 can apply a magnetic field 425 from the side of the magnetic tape 356, which is different from the magnetic field used to generate the magnetic bias. Generally, the magnetic field 425 can be described as having an arch shape or a horseshoe shape.

The leading edge of the magnetic field 425 maintains a magnetic orientation 422 in the directional octet IV, and the trailing edge of the magnetic field 425 produces a magnetic orientation 420 in the directional octet I. Therefore, only the portion of the servo mark formed by the magnetic field 425 has a residual magnetization with a directional octuple different from that of the magnetic bias. Since the portion of the magnetic tape 400 is not affected by the magnetic field 425, the magnetic orientations 418 and 422 remain the directional octet V. Therefore, the servo mark contains the remnant magnetization of the directional octet I, which is generally opposite to the directional octet IV of the magnetic bias. Further, the servo mark shown in FIG. 12B can be described as having a first magnetic orientation of the directional octet IV and a second magnetic orientation of the directional octet IV (eg, servo). The mark can include a magnetic orientation or remanent magnetization in substantially the same direction as the bias in the non-patterned region. As expected, the read signal 426 is similar to the read signal 412 of FIG. 12A. Includes an amplitude 428 and a pulse 430 (eg, a unipolar pulse) corresponding to a generally opposite directional octagonal change between the magnetic bias and the servo mark.

According to FIGS. 12A and 12B, the magnetic tape 400 includes a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. The servo track of the magnetic layer also includes servo patterned and non-patterned areas. The servo pattern includes a plurality of servo marks having a pattern residual magnetization of a directional octagonal circle I tangent to the vertical plane 23 orthogonal to the substrate. The non-patterned region, eg, magnetic bias, comprises the non-patterned remanent magnetization of the directional octet IV, which also touches the vertical plane 23. The octets I and IV are on the same side of the vertical plane 23, while the octets I and IV are on the opposite side of the longitudinal plane 21. That is, the vertical components of the octets I and IV are in opposite directions, and the longitudinal components of the octets I and IV are in the same direction.

The remanent magnetization in the octets I and IV may be configured to generate a read signal 426 (eg, servo signal) with a read head to identify each of the servo marks. Signal 426 if the residual magnetization of the magnetic tape 400 has a vertical component opposite to the vertical component of the bias magnetization and the residual magnetization matches or has the same longitudinal component of the bias magnetization. Can include an amplitude 428 (eg, a waveform) having a substantially unipolar pulse 430.

13A and 13B show a conceptual diagram of an exemplary magnetic medium containing a magnetic bias of a random directional octet, along with a graph of the corresponding readout signal. As shown in FIG. 13A, the magnetic tape 432 is an example of the magnetic tape 10. As shown in FIG. 13A, the magnetic tape 432 includes one or more servo patterns written to the random magnetic bias of the magnetic tape 242A of FIG. One or more servo patterns are written to the directional octets I and IV within the randomized bias or unwritten area. Randomized magnetic bias can result in virtually zero overall remanent magnetization.

A magnetic head 450, such as a servo write head, is used to form a servo pattern, i.e. some servo marks, on a randomized magnetic bias preformed on the magnetic tape 432. Random magnetic bias can be generated using alternating current or other techniques to eliminate identifiable signals from the magnetic layer of magnetic tape 432. When the magnetic tape 432 is driven or driven in the direction of arrow 292 so as to pass near the magnetic head 450, a servo mark is formed in the magnetic layer of the magnetic tape 432.

Similar to FIG. 9A, all arrows indicating the magnetic orientation of FIG. 13A are limited to the vertical and longitudinal components. The arrow in the vertical component portion 442 only indicates that the vertical component of the magnetic orientation in the magnetic layer is oriented away from the substrate, eg, 90 degrees. Therefore, the arrow of the longitudinal component portion 436 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is directed in the same direction as the arrow 292, eg, 0 degrees. Since these shaded portions of the tape 432 indicate that the magnetic orientation of the magnetic particles is randomized, the vertical component portions 440, 444 and 448 and the longitudinal component portions 434 and 438 include arrows. not. Thus, there is no overall residual magnetization in the magnetic bias, but the servo pattern can include magnetic orientation in the directional octets I and IV. FIG. 13B shows the direction of the overall magnetic orientation without the use of longitudinal and vertical components.

In order to form a servo pattern on the magnetic tape 432, the magnetic tape 432 is driven beyond the magnetic head 450 generating the magnetic field 451. The arrows in the magnetic field 451 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 451. The magnetic field 451 is generated in one direction as opposed to the alternating magnetic field used to generate the random bias of the tape 242A. The first portion of the magnetic field 451 applied to the magnetic tape 432 is directed in the direction of the magnetic tape 432. The middle portion of the magnetic field 451 is directed along the magnetic tape 432 in the direction of arrow 292. The last portion of the magnetic field 451 applied to the magnetic tape 432 is directed away from the substrate. Since this last portion of the magnetic field 451 has the last effect on the magnetic tape 432, the vertical component portion 442 is such that the vertical component of the magnetic orientation changes from the random magnetic bias shown in the vertical component portions 444 and 448. Is shown.

When the magnetic field 451 is applied to the magnetic tape 432, the leading edge of the magnetic field 451 changes the vertical component portion 446 from the vertical component portion 448 of the random magnetic bias. The intermediate portion of the magnetic field 451 also changes the longitudinal component portion 436 from the random bias of the longitudinal component portion 438 in the same direction as the arrow 292. In this way, the vertical component portions 446 and 442 and the longitudinal component portion 436 define different residual magnetizations of the servo marks in the directional octets I and IV. It should be noted that unless the magnetic field 451 is applied for a longer time than shown in FIG. 13A, a substantially longitudinal direction is generated within the servo mark.

FIG. 13A also shows an example of a read signal 452 of the magnetic orientation of the magnetic tape 432 detected by the read head. The amplitude 454 of the readout signal 452 fluctuates as the magnetic orientation of the particles in the magnetic layer changes between a random magnetic bias and different directional octets of servo marks over the length of the tape 432. Pulse 456 provides an amplitude change from a random orientation to a directional octet I, and pulse 458 provides an amplitude change from a random orientation to a directional octet IV. Pulses 456 and 458 can be described as bipolar or substantially symmetrical bipolar pulses.

As shown in FIG. 13B, the overall magnetic orientation of the magnetic tape 432 is illustrated instead of using the longitudinal and vertical components provided in FIG. 13A. The magnetic tape 432 is shown in the magnetic orientation shown in the magnetic tape 242B of FIG. The magnetic head 450 generates a magnetic field 471 applied to the magnetic tape 432 as the magnetic tape 432 is driven over the magnetic head 450 in the direction of arrow 292. The magnetic head 450 can apply a magnetic field 471 from the side of the magnetic tape 432 that is the same as or different from the magnetic field used to generate the randomized magnetic bias. Generally, the magnetic field 471 can be described as having an arch shape or a horseshoe shape.

The leading edge of the magnetic field 471 produces a magnetic orientation 466 of the directional octet IV from the randomized magnetic orientation 468. The trailing edge of the magnetic field 471 creates a magnetic orientation 462 in the directional octet I. The middle of the magnetic field 471 produces a substantially longitudinal orientation 464. Therefore, the entire servo mark generated by the magnetic field 471 has a magnetic orientation with a directional octet different from that of the randomized magnetic bias. The magnetic orientations 468 and 460 are randomized by the magnetic field 471 and remain unchanged. Therefore, the servo marks include magnetic orientations in the directional octets I and IV. As expected, the read signal 472 is similar to the read signal 452 of FIG. 13A. The readout signal 472 includes amplitudes 474 and pulses 476 and 478 that correspond to changes in the directional octet between the randomized magnetic bias and the written servo marks. Pulses 476 and 478 can be described as bipolar or substantially symmetrical bipolar pulses. Bipolar pulses may be perfectly symmetric, but in general, bipolar pulses can be substantially symmetric when the pulses 476 and 478 have approximately similar (but opposite) amplitudes and similar widths. ..

According to FIGS. 13A and 13B, the magnetic tape 432 includes a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. The servo track of the magnetic layer also includes servo patterned and non-patterned areas. The servo pattern includes a plurality of servo marks having a pattern residual magnetization in the directional octets I and IV. However, non-patterned regions, such as magnetic bias, include non-patterned remanent magnetization that is virtually zero. This minimum residual magnetization is due to the generally random magnetic orientation of the magnetic particles in the magnetic tape 432.

The residual magnetization of the servo mark is different from the substantial servo magnetization of the bias. The configuration of the magnetic tape 432 may be configured to generate a read signal 472 (eg, a servo signal) having a read head to identify each of the servo marks. If the bias magnetization has substantially randomized vertical and longitudinal components, the signal 472 can include an amplitude 474 (eg, a waveform) with substantially symmetrical opposite pulses 476 and 478. However, servo patterns with different directional octets may produce slightly different pulse shapes. As mentioned above, the pulses 476 and 478 can be collectively described as bipolar pulses. This bipolar pulse may be substantially symmetric.

Similar to any of the servo signals of FIGS. 9A-13B, the illustrated servo signal is not processed by the read head. That is, the signal detected from the residual magnetization of the magnetic tape can be substantially equivalent to the illustrated exemplary waveform. Post-processing can reproduce similar types of waveforms or pulses from magnetic tape with any residual magnetization, but any of this processing other than amplification detects similar waveforms from the above residual magnetization in magnetic tape. do not have to.

FIGS. 9A-13B generally describe remanent magnetization in a direction substantially perpendicular to the substrate, whereas bias and servomarks are due to remnant magnetization having a direction substantially parallel to the substrate. It may be formed. For example, the magnetic tape may include a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. The tape may also include a magnetic layer servo track and a non-patterned area. The servo pattern includes a plurality of servo marks having a pattern residual magnetization in the directional octagon II. However, non-patterned regions, such as magnetic bias, include non-patterned remanent magnetization in the directional octet VI. In this way, the servo marks and non-patterned regions may have opposite but substantially longitudinal residual magnetization. Servomarks with directional octets with substantially longitudinal and opposite remanent magnetization and other combinations of non-patterned regions also include octets VI and II, III and VII, and VII and III, respectively. good.

FIG. 14 is a conceptual diagram of an exemplary magnetic medium including the magnetic orientation of magnetic particles within a servo mark by the leading and trailing edges of a magnetic field and a graph of the corresponding readout signal. As shown in FIG. 14, the magnetic tape 480 is shown as magnetic orientations 484,486, and 488 and includes a magnetic layer formed on the substrate 482. The magnetic orientations 484 and 488 show the residual magnetization of the magnetic bias in the non-patterned region of the servo track and are approximately perpendicular to the substrate 482. However, in another example, the magnetic orientations 484 and 488 may be defined within a directional octet such as the directional octet V. The magnetic bias of the magnetic orientation 484 was generated before the servo mark of the magnetic orientation 486. That is, the servo mark and the servo pattern are separated by the non-pattern region of the magnetic bias. Although servo marks are described here, in other examples different regions or marks of magnetic orientation can be used to store data in the data track (eg, magnetic orientation is "1". Or the bit of information such as "0" can be determined).

The magnetic orientation 486 indicates the direction of the residual magnetization of one servo mark in the servo pattern. As the magnetic tape 480 travels past the head 490 in the direction of arrow 494, the magnetic orientation 486 is generated by applying a magnetic field 492 generated from the servo magnetic head 490 to the magnetic tape 480. The leading edge of the magnetic field 492 is in the direction toward the substrate 482, and the trailing edge of the magnetic field 492 is in the direction away from the substrate 482. Since the magnetic field 492 is applied to the magnetic tape during the current pulse in the head 490, the entire servo mark of the magnetic orientation 486 is generated by the distance of Pi in the pulse and the running of the magnetic tape 480 with a gap length G of the magnetic field 492. Will be done.

A portion of the servo mark has a magnetic orientation opposite to that of the magnetic bias, for example, a magnetic layer on Pi oriented substantially away from the substrate 494. However, the rest of the servo marks over the gap length G are not oriented substantially perpendicular to the substrate 482 and away from the substrate 482. Instead, the portion of the magnetic orientation 486 over the gap length G is variable according to the shape of the magnetic field 492. Therefore, the magnetic orientation 486 of the servo mark is variable and is not completely opposite to the direction of the magnetic bias. However, the trailing edge of the magnetic field 492 leaves a residual magnetization in the direction of the opposite directional eight-quarter circle I. This variability of magnetic orientation is due to the fact that the magnetic field 492 is applied to the bias already formed. When the magnetic field 492 is turned off, there is no trailing edge to remove the tip portion of the magnetic field 492. The magnetic biases of the magnetic orientations 484 and 488 are immediately next to the servo marks before and after the servo marks along the length of the tape 480.

The readout signal 496 indicates the amplitude 498 generated by the interface between the varying magnetic orientations on the tape 480. Pulse 500 exhibits a strong increase in amplitude due to the opposite and substantially vertical magnetic orientation between the magnetic bias and the trailing edge of the servo mark. However, the plateau 502 is made from a magnetic orientation that changes slowly over the gap length G. The plateau 502 can result in a relatively weak signal-to-noise ratio for the servo marks formed by the magnetic field 492.

The various magnetic orientations herein are generally described as forming a magnetic bias or servo mark (eg, some servo marks form a servo pattern). Therefore, magnetic biases and servo marks can be recorded as magnetic transitions along the magnetic tape. However, in other examples, bit information (eg, "1" or "0") can be defined with marks containing certain magnetic orientations. Magnetic transitions between marks can then be used to indicate information stored on magnetic tape. In this way, the techniques used here for servo marks and servo patterns are also applicable to data tracks.

FIG. 15 is a conceptual diagram of an exemplary magnetic medium including the magnetic orientation of magnetic particles in a servo mark by continuously writing the trailing edge of a magnetic field and a graph of the corresponding readout signal. As shown in FIG. 15, the servo magnetic head 490 and magnetic field 492 of FIG. 14 are used to form the servo mark. However, after writing the servo mark with the magnetic field 492, the magnetic head 490 switches the direction of the magnetic field 492 to generate a magnetic bias having a residual magnetization in the direction opposite to the magnetic orientation 510 of the servo mark.

The magnetic tape 504, shown as magnetic orientations 508, 510, and 512, includes a magnetic layer formed on the substrate 506. The magnetic tape may be the same as the magnetic tape 10. The magnetic orientations 508 and 512 show magnetic bias in the non-patterned region of the servo track and are approximately perpendicular to the substrate 506. However, in another example, the magnetic orientations 508 and 512 may be defined within a directional octet, such as a directional octet V. The magnetic orientations 508 and 512 of the magnetic bias and the magnetic orientation 510 of the servo marks were sequentially created without stopping the running of the magnetic tape 504 in the direction of arrow 494. The servo marks and servo patterns on the magnetic tape 504 are separated by a non-pattern area of magnetic bias.

Magnetic orientation 510 indicates the magnetic orientation of one servo mark in the servo pattern. As the magnetic tape 504 travels past the head 490 in the direction of arrow 494, the magnetic orientation 510 is generated by applying a magnetic field 492 generated from the servo magnetic head 490 to the magnetic tape 504. Only the trailing edge of the magnetic field 492 oriented substantially away from the substrate 506 is used to generate the magnetic orientation 510 of the servo marks. That is, the magnetic field 492 is applied to the magnetic tape 504 during the current pulse in the head ₄₉₀ over the entire distance P2 of the servo mark. The gap length G extends into the non-servomark region (non-pattern region) of the magnetic tape 504, while the magnetic head 490 switches the magnetic field 492 so that the new trailing edge aligns with the magnetic bias direction magnetic orientation 512. , Or invert.

Using this alternating magnetic field technique, the trailing edge of the magnetic field 492 forms the entire servo mark with a magnetic orientation 510 substantially perpendicular to the substrate 506 and magnetic orientations 508 and 512 opposite to the magnetic bias. .. That is, the residual magnetization of the magnetic field 510 is the direction in the directional octet I and has the direction opposite to the magnetic bias of the directional octet V. Therefore, before and after the servo mark along the length of the magnetic tape 504, the magnetic biases of the magnetic orientations 508 and 512 are directly adjacent to the remanent magnetization of the servo marks of the magnetic orientation 510. Also, the transition between the magnetic orientations 508 and 512 of the non-patterned region and the magnetic orientation 510 of the servo pattern includes, for example, only the remanent magnetization in two directions of two opposite octets. In the example of magnetic tape 504, the transition comprises a direction substantially perpendicular to the substrate 506 in a direction towards and away from the substrate.

The readout signal 514 indicates the amplitude 516 generated by the interface between the varying magnetic orientations on the tape 504. Pulse 518 exhibits a strong increase in amplitude due to the opposite and substantially vertical magnetic orientation between the magnetic bias and the servo mark. In addition, the transition from the servo mark to the magnetic bias also results in a large change in amplitude as indicated by pulse 520. By alternating the magnetic fields to continuously create the magnetic bias and the servo mark, the signal-to-noise ratio of the servo mark in FIG. 15 may be greater than the signal-to-noise ratio of the servo mark in FIG.

16A and 16B are conceptual diagrams of a single magnetic head that writes a servo pattern by alternating the direction of the magnetic field. The magnetic tape 522 may be similar to the magnetic tape 504 described with reference to FIG. Generally, as the magnetic tape 522 passes near the magnetic head 534, the magnetic head 534 is stationary, alternating between magnetic fields 536A and 536B (collectively referred to as "magnetic fields 536") in opposite directions. By alternating the magnetic fields 536, magnetic biases (eg, non-patterned regions) can be continuously generated using the servo marks of the servo pattern. The switching of the alternating magnetic field or the magnetic field can be timed to correspond to the predetermined length of the servo mark and the non-pattern bias region of the magnetic tape 522.

When the magnetic tape 522 travels in the direction of the arrow 538 that has passed through the magnetic head 534, any of the magnetic fields 536 is applied to the magnetic tape 522. As shown in FIG. 16A, a magnetic bias with magnetic orientation 526, such as residual magnetization, is already formed on the tape 522. The direction of the magnetic orientation 526 is substantially perpendicular to the substrate 524 and is oriented towards the substrate. After the magnetic orientation 526 was formed, the magnetic head 534 was switched to a magnetic field 536A. The magnetic field 536A is approximately directed along the length of the magnetic tape 522 in the same direction as arrow 538. The magnetic field 536A is generated such that the trailing edge of the magnetic field _536A is applied to the magnetic tape 522 over a length P3. P3 also corresponds to the current pulse used to generate the magnetic field _536A . Therefore, the magnetic orientation 528 of the servo mark is generated between transitions A and B.

Before the magnetic head 534 alternates with a magnetic field having different directions, the magnetic field 536A produces a magnetic orientation 530 that mimics the changing orientation of the magnetic field 536A. The rest of the magnetic tape 522 shown in FIG. 16A is unaffected by the magnetic field from the magnetic head 534. Therefore, the magnetic orientation 532 can include various random magnetic orientations of the magnetic particles. In another example, the magnetic orientation 532 can have some degree of magnetic orientation uniformity from the configuration of the magnetic tape 522.

When the transition B of the continuously traveling magnetic tape 522 reaches the rear end of the magnetic field 536A, for example, when the servo mark of the magnetic orientation 528 is completed, the magnetic head 534 alternately moves from the direction of the magnetic field 536A to the direction of the magnetic field 536B. Switch. As shown in FIG. 16B, the magnetic head 534 generates a magnetic field 536B when the trailing edge of the magnetic field reaches transition B. The magnetic field 536B may be generated by a directing current, for example, as controlled by the controller 30 of the servo writing system 26 of FIG. In some examples, the current may be a modulated or controlled alternating current over the time required to generate the desired length of servo marks and non-pattern bias regions on the tape 522. ..

The magnetic field _536B is applied to the magnetic tape 522 over a length P4 to form a magnetic bias, eg, a magnetic orientation 540 in a non-patterned region. P4 also corresponds to the current pulse used to generate the magnetic field _536B . The magnetic orientation 540 extends along the length of the magnetic tape 522 between transitions B and C. After the transition C, the magnetic head 534 can alternate with the magnetic field 536A again to form another servo mark of the servo pattern. Similar to the magnetic orientation 530 of FIG. 16A, the magnetic orientation 542 mimics the direction of the magnetic field 536B until the trailing edge of the magnetic field 536A changes orientation.

The magnetic tape 522 contains a magnetic bias, eg, a non-patterned region, that is directly adjacent to the servo mark. In this way, transitions A, B, and C have a substantially vertical orientation towards the substrate 524 and an opposite substantially vertical orientation away from the substrate 524. Continuously writing magnetic biases and servo patterns with alternating magnetic fields can allow for larger signal-to-noise ratios in the servo track of vertical media. In addition, writing servo patterns and biases in one continuous step reduces the amount of time required to create the number of systems required to manufacture user-friendly magnetic storage tapes and tapes.

17A and 17B are conceptual diagrams of the gap width of the magnetic head 544 and the servo mark 552 having a length W substantially equal to the gap width W. As shown in FIG. 18A, the magnetic head 544 includes a gap formed by the gap ends 546 and 548. The distance between the gap ends 546 and 548 is the gap width W. The magnetic field used to bias the magnetic tape and write the servo patterns and data is generated between the gap ends 546 and 548.

Typically, the gap width W is about 1.4 μm long. The length of the servo mark is about 2.1 μm. Therefore, a magnetic field is applied to the magnetic layer due to the pulse timed so that the magnetic tape has a gap width of about 0.7 μm. The gap width W and the resulting running of the magnetic tape results in an overall mark length of approximately 2.1 μm.

Instead of relying on the running of the tape during the application of a magnetic field, the gap width W can be adjusted to the approximate length of the servo mark. The magnetic head 544 can be configured with a desired gap width W, and the magnetic head 544 can be adjusted to the desired length of the servo mark. Since the adjustment of the gap width W can affect the shape of the magnetic field, the current and / or distance between the magnetic head 544 and the magnetic tape is such that the desired magnetic orientation of the servo marks in the magnetic tape is achieved. May be adjusted to.

As shown in FIG. 18B, the side sectional views of the magnetic tape 550 include servo marks 552A to C (collectively referred to as "servo marks 552") and 553A to C (collectively referred to as non-patterned regions 553). The magnetic tape 550 is passed in the vicinity of the magnetic head 544 and can form a servo mark 552 having a mark length B substantially equal to the gap width W of the magnetic head 544. Since the mark length is approximately equal to the gap width W, the magnetic field may be generated by the magnetic head 544 for a very short time, eg, during a momentary pulse of current. Even if the magnetic tape 550 is running when a magnetic field is applied to write the servo mark 552, the magnetic field is applied for a sufficiently short time so that the mark length B is substantially equal to the gap width W. As shown in the example of FIG. 18B, each of the servo marks 552 (eg, the region of the magnetic tape 550) is separated by a non-patterned region 553 (eg, the bias remaining in the space between the servo marks 552). .. In another example, the servo mark 552 and / or the non-patterned area 553 can indicate data, for example, the magnetic head 544 uses a magnetic field to replace the servo mark 552 on the data track of the magnetic tape 550. Data marks can be formed.

Short current pulses can generally occur in the short period between 10 and 50 nanoseconds. In one example, the short period may be about 30 microseconds or less. For a short period of time, the magnetic tape may at least partially depend on the speed at which it passes through the magnetic head, for example, a faster tape speed may require a shorter current pulse. In general, the mark length B and the gap width W may be equal to about 2.1 μm. Other dimensional examples such as a mark length of about 1.0 μm are also conceivable. For example, the gap between mark lengths B and W is generally between about 0.1 μm and 20 μm. More specifically, the mark length B may be between about 0.5 μm and 3.0 μm. Any dimension is possible as long as the mark length B and the gap width W are approximately equal.

FIG. 18A is a conceptual diagram of the magnetic head 564 forming the symmetric servo mark 561 formed by the magnetic field 566 corresponding to the mark length B of the symmetric servo mark 561. As shown in FIG. 18A, the symmetric servo mark 561 is generated by applying a magnetic field 566 for a short period of time that prevents the traveling magnetic tape 554 from traveling substantially through the magnetic field 566. The magnetic tape 544 may be similar to the magnetic tape 10. The magnetic tape 544 includes a substrate 556 and a magnetic layer indicated by magnetic orientations 558,560, and 562. The magnetic tape 544 is driven or run past the magnetic head 564 (eg, write head). Upon generation of the magnetic field 556, the magnetic orientation 560 is switched from the orientation of the magnetic bias shown in the magnetic orientations 558 and 562 to the orientation of the magnetic orientation 560.

As described with reference to FIGS. 17A and 17B, the mark length B is substantially equal to the gap length G of the magnetic head 564. Since the trailing edge of the magnetic field is longer in the servo mark, the magnetic orientation 560 of the symmetric servo mark 561 does not have to be symmetric anymore if the mark length B is larger than the gap length G. The magnetic orientation 560 is the orientation of the symmetric servo mark 561. The symmetric servo mark 561 includes a variable magnetic orientation 560 that varies along the mark length B. The magnetic orientation 560 is approximately equal to the direction of the magnetic field 566 and may be axisymmetric.

The magnetic head 564 can generate a magnetic field 566 by means of magnetic field lines having specific characteristics. For example, the magnetic field 566 may include a first magnetic field pattern region at the leading edge of the magnetic field 566 that is substantially perpendicular to the magnetic tape at the first end of the symmetric servo mark and directed towards the magnetic tape. (For example, adjacent to magnetic orientation 562). The magnetic field 566 may also include a second magnetic field pattern region at the trailing edge of the magnetic field that is substantially perpendicular to the magnetic tape at the second end of the symmetric servo mark and away from the magnetic tape (eg, magnetic orientation). Adjacent to 558). Further, the magnetic field 566 may include a third magnetic field pattern region that is substantially parallel to the magnetic tape and between the first and second ends (eg, the middle portion of the magnetic field 566).

In general, the angle between the first magnetic field pattern region (leading edge) and the substrate 556 is approximately equal to the angle between the second magnetic field pattern region (at the trailing edge) and the substrate 556.17. May be good. In one example, the magnetic directions of both the first magnetic field pattern region and the second magnetic field pattern region can form an angle with the substrate 556 that is greater than about 45 degrees. In another example, the magnetic directions of both the first magnetic field pattern region and the second magnetic field pattern region can form an angle with the substrate 556 that is greater than about 75 degrees. However, in some examples, the angle between the first and second magnetic field pattern regions and the substrate 556 may be about 90 ° (eg, perpendicular to the substrate 556). good.

The magnetic field 566 can form a similarly oriented symmetric servo mark 561. Within the magnetic orientation 560, one end of the symmetric servo mark 561 is substantially perpendicular to the substrate 556 and contains a magnetic orientation directed at the substrate 556, the other end of the symmetric servo mark 561 is a base. Substantially perpendicular to material 556, including magnetic orientation away from substrate 556, the middle portion of the symmetrical servo mark 561 between the two ends is substantially parallel to substrate 556. Includes magnetic orientation.

FIG. 18B is a timing diagram of a current pulse 572 that generates a magnetic field used to form the symmetric servo mark 561 of the magnetic tape 554 described with reference to FIG. As shown in FIG. 18B, timing diagram 570 shows the current used to generate a magnetic field to form a symmetric servo mark on the magnetic tape. The pulse 572 has a very short pulse width P. The pulse 572 can be generated and / or controlled, for example, by the controller 30 in FIG. The pulse width P can be as short as possible. Ideally, the pulse width P could approach substantially zero and the pulse 572 could approach the moment. The pulse width P is generally between 10 and 50 nanoseconds in duration. In one example, the short period of pulse width P may be about 30 microseconds or less. For a short period of time, the magnetic tape may at least partially depend on the speed at which it passes through the magnetic head, for example, a faster tape speed may require a shorter current pulse.

In some examples, the pulse 572 may be substantially a square wave. In another example, the pulse 572 may have a more complex shape. For example, the controller 30 can increase the current amplitude of the pulse 572 as quickly as possible. The controller 30 can then shut off or stop the current once the current amplitude reaches a predetermined threshold. Alternatively, the controller 30 can increase the current amplitude of the pulse 572 after a short period of time or termination. Therefore, the delivery of short pulses can be controlled by threshold amplitude or time cycle. In any case, the pulse 572 is relatively instantaneous with respect to the speed of the magnetic tape 554 traveling near the magnetic head 564.

19A and 19B show a conceptual diagram of a magnetic medium with a bias and a symmetric servo mark created on the corresponding read signal. As shown in FIG. 19A, the magnetic tape 574 includes a substrate 576, magnetic orientations 578 and 582, and a symmetric servo mark 580. The magnetic tape 574 and the symmetric servo mark 580 can be substantially similar to the magnetic tape 554 and the symmetric servo mark 561 of FIG. 18A, respectively. For example, the symmetric servo mark 580 may be formed by a magnetic field similar to the magnetic field of the magnetic field 566 of FIG. 18A. In general, the magnetic tape 554 can include one or more servo tracks, each containing a plurality of symmetric servo marks 580 each forming a servo pattern on each servo track. However, one or more data tracks can also contain symmetrical data marks.

Magnetic orientations 578 and 582 indicate the general magnetic orientation of the magnetic particles at a particular position on the magnetic tape 574. Magnetic orientations 578 and 582 also indicate the direction of the bias provided to the tape 574. The magnetic biases of the magnetic orientations 578 and 582 may be generated prior to the formation of the symmetric servo mark 580. The biases of the magnetic orientations 578 and 582 are indicated by the directional octet III with respect to the direction of tape travel indicated by arrow 584. Thus, the magnetic bias generated by the magnetic orientations 578 and 582 in the non-patterned region of the servo track can be defined by both the vertical and longitudinal components (eg, the non-zero vertical component and the non-zero). Longitudinal component). However, other examples of magnetic bias can include either perfectly vertical (zero longitudinal component) or fully longitudinal (zero vertical component) magnetic orientation.

The symmetric servo mark 580 includes segments A, B, C, D, and E. These segments are used to account for the magnetic features of the Symmetric Servo Mark 580. The change in magnetic orientation of the magnetic particles in the symmetric servo mark 580 can generally be continuous from one end to the other end of the symmetric servo mark 580. For example, the magnetic orientation at the rear of the symmetric servo mark 580 (segment E) may start at about 170 degrees and gradually change to 90 degrees in the middle of segment C. Next, the magnetic orientation of the middle portion of segment C may be progressively changed up to about 10 degrees in front of the symmetric servo mark 580 (segment A). However, the five segments A, B, C, D and E shown in FIG. 19A provide a general change in the magnetic orientation of the magnetic particles within the symmetric servo mark 580. The coordinate system described in FIG. 2A, defined by axes 21 and 23, is used to describe the changing magnetic orientation.

The symmetric servo mark 580 may be described symmetrically because the angle formed between the substrate 576 and the magnetic orientation is substantially reflected from the front of the servo mark to the rear of the servo mark. For example, segment A indicates that the anterior portion of the symmetric servo mark 580 has a magnetic orientation of about 10 degrees (with respect to FIG. 2A). Therefore, the magnetic orientation of segment A forms an angle of about 80 degrees on the substrate 576. Segment E shows that the rear of the symmetric servo mark 580 has a magnetic orientation of about 170 degrees (with respect to FIG. 2A). However, this 170 degree orientation also forms an angle of about 80 degrees under the substrate 576. In this way, the angles formed by the magnetic orientations of segments A and E are approximately equal. In general, the magnetic orientation of segments A and E can form an angle of approximately 45 degrees or more with the substrate 576. In another example, the magnetic orientation of segments A and E can form an angle of approximately 75 degrees or more with the substrate 576. The magnetic orientations of the respective segments A and E do not face each other directly (for example, the segments A and E have exactly the opposite magnetic orientations if the magnetic orientations are 180 degrees apart), but are magnetic with respect to the substrate 576. The symmetric servo mark 580 is still described symmetrically because the angle formed by the orientation is substantially the same between the front of the servo mark and the rear of the servo mark.

Like segments A and E, segments B and D are also symmetric. For example, segment B indicates that the anterior middle portion of the symmetric servo mark 580 has a magnetic orientation of about 60 degrees. Therefore, the magnetic orientation of segment B forms an angle of approximately 30 degrees on the substrate 576. Segment D indicates that the rear middle portion of the symmetric servo mark 580 has a magnetic orientation of about 120 degrees. However, this 330 degree orientation also forms an angle of about 30 degrees under the substrate 576. Therefore, the magnetic orientations of segments B and D are substantially symmetric. Segment C has a magnetic orientation of about 90 degrees, which is symmetric in the middle of the symmetric servo mark 580.

In some examples, the magnetic orientation of segments A, B, C, D, and E can at least partially define the lines of magnetic force within the symmetric servomark 580 of the tape 574. These lines of magnetic force may correspond to the lines of magnetic force generated by the magnetic field used to generate the magnetic orientation of the magnetic particles within the mark length B of the symmetric servo mark 580. In general, the lines of magnetic force at least partially defined by the magnetic orientation of the symmetric servo mark 580 can form an arch shape over the entire length of the symmetric servo mark 580 (eg, over the full mark length B). This arch shape may have different radii of curvature based on the magnetic field used to form the symmetric servo mark 580.

In another example, the particular angle of magnetic orientation within the symmetric servo mark 580 can vary. That is, the angle of magnetic orientation within segments A and E may be close to 0 degrees in other examples. The exact angle of the symmetric servo mark 580 with respect to the substrate 576 produced by the magnetic orientation can vary, but the magnetic orientation before and after the symmetric servo mark 580 may remain substantially symmetrical.

The symmetric servo mark 580 may have a residual magnetization different from that shown in FIG. 19A. For example, the symmetric servo mark 580 can be generated by a first portion of a magnetic field pattern that is substantially perpendicular to one direction and a second portion of a magnetic field pattern that is substantially perpendicular to the opposite direction. The middle portion of the servo mark 580 can retain the same residual magnetization as that of the previous magnetic bias. This type of symmetric servo mark 580 may exist in a state where the magnetic orientation is randomized so that the erased bias, for example, the residual magnetization is substantially zero.

As shown in FIG. 19B, the readout signal 586 shows the amplitude 588 produced by the interface between the magnetic orientations that varies over the length of the tape 574 shown in FIG. 19A. Pulse 590 exhibits a strong increase in amplitude due to the opposite and substantially vertical magnetic orientation between the magnetic bias of the magnetic orientation 578 and the segment A of the symmetric servomark 580 of the servo mark. In addition, the transition from the symmetric servo mark 580 segment E to the magnetic bias of the magnetic orientation 578 also results in a large change in amplitude as indicated by pulse 592. The changing magnetic orientation within the symmetric servo mark 580 produces the amplitude change shown between the pulses 590 and 592.

FIG. 20 is an example for using two magnetic heads to generate either a longitudinal bias or a longitudinal bias on a magnetic tape, eg, substantially vertical remanent or longitudinal remanence. It is a flow chart showing a specific technique. In the example of FIG. 20, the system 26 and the magnetic tape 32 will be described. However, a longitudinal bias or a vertical bias may be generated on any of the magnetic tapes described herein having a larger vertical angular ratio (eg, magnetic tape 10).

As shown in FIG. 20, the magnetic tape 32 is supplied between two magnetic heads (eg, two heads in the servo head module 28) (600). The system 26 drives the magnetic tape 32 in the first direction towards both magnetic heads (602). The first head generates a magnetic field from one side (plane A) of the magnetic tape 32, which is generally oriented in the first direction along the magnetic tape 32 (604). An example of the first head is a magnetic head 110 that generates a magnetic field 111 as shown in FIG. 6A. This magnetic field can create a magnetic orientation similar to the trailing edge of the magnetic field.

When the magnetic bias is longitudinal (“YES” branch of block 606), the second magnetic head generates a magnetic field from the other side (plane B) of the tape 32, and the magnetic field is generally on the tape 32. Oriented along the first direction (608). An example of this second head is a magnetic head 112 that generates a magnetic field 113 as shown in FIG. 6A. The resulting magnetic bias generated on the tape 32 after step 608 is substantially a longitudinal magnetic bias. That is, the vertical component of the magnetic orientation in the bias is almost zero.

When the magnetic bias is vertical (“NO” branch of block 606), the second magnetic head generates a magnetic field from the other side (plane B) of the tape 32, and the magnetic field is generally on the tape 32. Oriented along a second direction opposite to the first direction (610). An example of this second head is a magnetic head 162 that generates a magnetic field 163 as shown in FIG. 7A. The resulting magnetic bias generated on the tape 32 after step 610 is a substantially vertical magnetic bias. That is, the longitudinal component of magnetic orientation in the bias is almost zero.

After the magnetic bias is generated on the magnetic tape 32 by the magnetic field of one of steps 608 or 610, the magnetic tape 32 can be further prepared for data storage. For example, one or more servo patterns can be formed in the servo track of the magnetic tape 32. This servo write process can proceed according to any of the various techniques described herein.

FIG. 21 is a flow diagram illustrating an exemplary technique for generating a bias in a one-way octet and forming a servo pattern of the directional octet different from the bias. The technique of FIG. 21 targets exemplary servo marks formed by the magnetic fields of FIGS. 9A-13B. For illustrative purposes, FIG. 21 describes the magnetic bias and servomark described in FIG. 9B, which writes a servo mark on a magnetic tape 280 using a magnetic head 290 and a magnetic field 307. Although different magnetic heads are described as forming bias and servo marks, the same magnetic head can be used in other examples.

As shown in FIG. 21, the user can select the desired directional octet for magnetic bias (624). The choice of directional octet for magnetic bias is based on any number of factors, such as the expected signal-to-noise ratio of the completed servo pattern, the magnetic field that can be generated, or the particular composition of the magnetic tape. You may. In the example of FIG. 21, the selected directional octet for magnetic bias may be directional octet I as shown in FIG. 9B.

The magnetic tape 280 is then oriented to the bias head (magnetic head), allowing the magnetic bias to be generated within the directional octet I (626). The bias head then generates a magnetic field in the required direction (eg, in the same direction as the running of the magnetic tape) to generate a magnetic bias in the directional octet I (628). Therefore, after the magnetic tape 280 has passed near the bias head, the magnetic tape 280 contains a magnetic bias in the directional octet I. As shown in FIG. 9B, the magnetic bias can include a magnetic orientation 304.

The magnetic tape 280 is then placed and driven over the magnetic head 290 (eg, servo head) to form a servo pattern using the plurality of servo marks (630). In the example of FIG. 9B, the base material of the magnetic tape 280 is arranged at a position away from the magnetic head 290. The magnetic head 290 then writes a servo mark to form a directional octagonal servo pattern that is different from the previously generated magnetic bias (632). In the example of FIG. 9B, the magnetic head 290 generates a magnetic field 307 in the traveling direction of the magnetic tape 280, and a servo mark including a residual magnetization of a directional octagonal circle IV substantially opposite to the bias direction of the octagonal circle I. To form. Each time a magnetic field 307 is generated and applied to the magnetic tape 280, a new servo mark with a magnetic orientation different from the bias is formed.

In general, the residual magnetization of the bias (eg, the non-patterned region) and the plurality of servo marks have opposite directional octagonal directions. Opposite octets, such as the octets shown in FIGS. 9-12, do not have to be completely opposite to each other. The completely opposite octets, eg, octet pairs I and V or VIII and IV, have three other octets that separate them. It can be mentioned that at least two other octets, eg, octets separated by the octets pair I and IV or V and VIII, are generally opposite to each other. That is, for example, both the longitudinal and vertical components of the octagonal circles I and V are opposite to each other. In figure skating pairs I and IV, the vertical components are in opposite directions, but the longitudinal components share a common direction.

FIG. 22 is a flow chart illustrating an exemplary technique for continuously biasing and writing a servo pattern by alternating the direction of a magnetic field. FIG. 22 is schematically illustrated with the magnetic head 534, magnetic field 536, and magnetic tape 522 of FIGS. 16A and 16B. However, this technique can also be used to form bias and servo patterns on other magnetic tapes (eg, magnetic tape 10).

As shown in FIG. 22, the servo write system (eg, system 26 in FIG. 3) drives the magnetic tape 522 beyond a single magnetic head 534 (634). When the magnetic tape 522 travels, the magnetic head 534 generates a magnetic field 536B in the first direction, creating a magnetic bias on the magnetic tape 522 (636). When the magnetic head 534 writes the servo mark of the servo pattern (“YES” branch of block 638), the magnetic head 534 switches the magnetic field to generate a magnetic field 536A in the second direction and servos at the trailing edge of the magnetic field 536A. Write the mark (642). Since the magnetic head 534 switches the direction of the magnetic field 536B, the second direction is opposite to the first direction. In this way, the magnetic orientation of the magnetic bias is substantially opposite to the servomark magnetic orientation. After writing the servo mark (642), the magnetic head 534 switches again from magnetic field 536A to magnetic field 536B to generate a magnetic bias (636). In this way, the magnetic head 534 can continuously alternate or switch the direction of the magnetic field in order to continuously generate either a magnetic bias or a servo mark.

If the magnetic head 534 does not write the servo mark ("NO" branch of block 638) and the write process is not completed ("NO" branch of block 640), the magnetic head 534 continues to generate magnetic field 534B ("NO" branch of block 640). 636). However, if the magnetic head 534 should not write the servo mark (the "NO" branch of block 638) and the write process is complete (the "YES" branch of block 640), the magnetic head 534 will stop generating the magnetic field (the "YES" branch of block 640). 644).

FIG. 23 is a flow chart illustrating an exemplary technique for forming a symmetric servo mark on a magnetic storage tape. FIG. 23 is schematically illustrated with the magnetic head 564, magnetic field 566, and magnetic tape 554 of FIG. 18A. However, this technique can also be used to form symmetric servo marks on other magnetic tapes (eg, magnetic tape 10). This technique aims to write a symmetric servo mark for a servo pattern, but it is also possible to write a symmetric servo mark as a data mark in a data track.

As shown in FIG. 23, the servo write system (eg, system 26 in FIG. 3) drives the magnetic tape 554 over a single magnetic head 564 (646). The magnetic tape 554 may already have a magnetic bias formed on the tape. If the magnetic head 564 writes the servo mark (“YES” branch of block 648), the controller 30 determines the appropriate magnetic field (eg, the direction of the magnetic field) and the desired residual magnetization to achieve the desired waveform from the servo mark. Can be generated (651). In this way, as described herein, a magnetic field can be written on the servo mark to achieve a particular remanent magnetization within the octuple. Based on the bias magnetization of the magnetic tape 554, the resulting servo marks can achieve a particular waveform when read by the readhead. The magnetic head 564 then delivers a flash pulse of magnetic field 566 in a short period of time (652). That is, the magnetic field 566 is generated for a short period of time such that the magnetic field 566 is not applied to the magnetic tape 554 when the tape is running. As described herein, the short term can generally be about 10 nanoseconds to 50 nanoseconds or less. The magnetic field 566 produces a magnetic orientation over the entire length of the servo mark of the substantially symmetrical magnetic tape 554.

If the magnetic head 564 does not write the servo mark (the "NO" branch of block 648), but writes more servo marks to the tape 554, the system continues to drive the tape 544 with the servo marks as symmetric servo marks. Continue to write. If the magnetic head 564 does not write the servo mark (the "NO" branch of block 648), but writes more servo marks to the tape 554, the system has stopped the tape 544 because the servo write process is complete. Let (654).

In another example, the symmetric servo marks for the servo pattern can be written using multiple magnetic heads that are consecutively aligned along the tape path. The flash pulse of the magnetic field can then be supplied simultaneously by all the magnetic heads to form symmetric servo marks at the same spacing of the magnetic heads. In this way, a plurality of servo marks of the servo pattern can be written at the same time.

Various different bias and servo writing techniques are described herein in connection with magnetic recording media that define a larger vertical square ratio. Each of these techniques can be used alone or in any combination to generate remanent magnetization in the desired direction. Each of the magnetic tapes described herein is also a portion of the entire magnetic tape, each portion being described as an exemplary portion within the magnetic tape.

(1)
With the base material
A magnetic layer formed on the substrate, comprising a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%.
The servo track on the magnetic layer and
A servo pattern in the servo track, the servo pattern including a plurality of servo marks each having a pattern residual magnetization in a first direction substantially perpendicular to the substrate.
A non-patterned region within the servo track located immediately next to and between the plurality of servo marks, substantially perpendicular to the substrate and in a second direction opposite to the first direction. Data storage tape with non-patterned regions defining non-patterned residual magnetization.
(2)
The data storage tape according to (1), wherein the non-patterned residual magnetization in the second direction is a magnetic bias in the non-patterned region.
(3)
The data storage tape according to (1) or (2), wherein each of the plurality of servo marks is arranged alternately with a non-patterned region along the length of the magnetic layer.
(4)
The transition between each of the plurality of servo marks and the non-patterned region substantially comprises the pattern remanent magnetization in the first direction and the non-pattern remnant magnetization in the second direction (3). The data storage tape described in.
(5)
The residual magnetization comprises a vertical component perpendicular to the substrate and a longitudinal component parallel to the substrate, the longitudinal component being less than 50% larger than the vertical component. The data storage tape according to any one of 1) to (5).
(6)
The data storage tape according to (5), wherein the longitudinal component is less than 25% larger than the vertical component.
(7)
The data storage tape according to any one of (1) to (6), further comprising a data track on the magnetic layer.
(8)
A step of passing a magnetic tape near a magnetic head, wherein the tape has a magnetic layer with a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%, a servo track, and data. With steps, including with tracks,
A step of generating a first magnetic field in a first direction along the magnetic tape having the magnetic head, and a step of generating a second magnetic field in a second direction along the magnetic tape by the magnetic head. And how to provide.
(9)
The method according to (8), wherein the step of passing the magnetic tape in the vicinity of the magnetic head is continuous during the alternation of the first magnetic field and the second magnetic field.
(10)
The step of alternately generating the first magnetic field and the second magnetic field further includes applying a controlled alternating current to the magnetic head (8) or (9). ).
(11)
The method according to any one of (8) to (10), wherein the first magnetic field generates a magnetic bias in the servo track having a residual magnetization in the first direction.
(12)
The method according to (11), wherein the second magnetic field forms a servo mark on the servo track having a residual magnetization in a second direction opposite to the first direction.
(13)
From (8) further comprising the step of using either the trailing edge of the first magnetic field or the trailing edge of the second magnetic field to generate a residual magnetization in the magnetic layer that is substantially perpendicular to the magnetic tape. The method according to any one of (12).
(14)
The first magnetic field and the second magnetic field each have an arched magnetic field pattern with magnetization that is substantially perpendicular to the magnetic tape at both the front and trailing edges of the first and second magnetic fields. The method according to any one of (8) to (13), which includes.
(15)
A tape drive configured to run a magnetic tape, wherein the magnetic tape comprises a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%, a servo track, and a servo track. With tape drives, including data tracks,
A step of generating a first magnetic field in a first direction along the magnetic tape and a second in a second direction along the magnetic tape while the magnetic tape is running near the magnetic head. A system comprising said magnetic head configured to alternate between steps of generating a magnetic field.
(16)
When the magnetic head alternately generates the first magnetic field and the second magnetic field, the tape drive continuously runs the magnetic tape near the magnetic head, (15). The described system.
(17)
A magnetic field generation circuit is further provided, wherein a controlled alternating current is applied to the magnetic head to alternately perform a step of generating the first magnetic field and a step of generating the second magnetic field (15). Or the system according to (16).
(18)
The magnetic field generation circuit is controlled so that the first magnetic field is applied to the magnetic tape so as to generate a magnetic bias on the servo track having the residual magnetization in the first direction. The second magnetic field is controlled so that the second magnetic field forms a plurality of servo marks on the servo track having the residual magnetism in the second direction opposite to the first direction. 17) The system according to (17), further comprising a processor configured to apply a magnetic field to the magnetic tape.
(19)
The magnetic head generates both the first magnetic field and the second magnetic field, and uses either the trailing edge of the first magnetic field or the trailing edge of the second magnetic field on the magnetic tape. The system according to any one of (15) to (18), configured to generate remanent magnetization on the magnetic tape that is substantially vertical.
(20)
The magnetic head is of the first and second magnetic fields having an arched magnetic field pattern substantially perpendicular to the magnetic tape at the front and trailing edges of both the first and second magnetic fields. The system according to any one of (15) to (19), which is configured to generate both.
(21)
The step of passing the magnetic tape near the write head,
A method comprising a step of generating a short-term magnetic field by the write head to form a symmetric servo mark on a magnetic tape defining a mark length approximately equal to the gap width of the write head.
(22)
The step of generating the magnetic field is a first magnetic field pattern region that is substantially perpendicular to the magnetic tape at the first end of the symmetric servo mark and is directed to the magnetic tape.
A second magnetic field pattern region at the second end of the symmetric servo mark that is substantially perpendicular to the magnetic tape and away from the magnetic tape.
The step according to (1), comprising a step of generating a magnetic field having a third magnetic field pattern region substantially parallel to the magnetic tape between the first end and the second end. Method.
(23)
The method according to (2), wherein each of the first magnetic field pattern region and the second magnetic field pattern region has a direction forming an angle of 45 degrees or more with the magnetic tape.
(24)
The method according to (22) or (23), wherein each of the first magnetic field pattern region and the second magnetic field pattern region has a direction forming an angle of 75 degrees or more with the magnetic tape.
(25)
Each of the first magnetic field pattern regions forms a first angle with the magnetic tape, and the second magnetic field pattern region forms a second angle with which the magnetic tape is approximately equal to the first angle (21. ) To (24).
(26)
The method according to any one of (21) to (25), wherein the step of generating the magnetic field includes a step of increasing the current to a threshold value and stopping the current within a short period of time.
(27)
The method according to any one of (21) to (26), wherein the step of generating the magnetic field includes a step of increasing the current and stopping the current immediately after the short period of time elapses.
(28)
The method according to any one of (21) to (27), wherein the short period is between about 10 nanoseconds and 50 nanoseconds.
(29)
The magnetic field is applied to the servo track of the magnetic tape having a magnetic bias to provide a mark length between about 0.5 micrometer and 3.0 micrometer as at least part of the servo pattern in the servo track. The method (30) according to any one of (21) to (28), further comprising a step of forming the symmetrical servo mark having.
A tape drive that runs magnetic tape,
A write head configured to generate a magnetic field across the gap width in a short period of time to form a symmetric servo mark on the magnetic tape defining a mark length approximately equal to the gap width of the write head. Prepare, system.
(31)
The write head
A first magnetic field pattern region that is substantially perpendicular to the magnetic tape at the first end of the symmetric servo mark and is directed at the magnetic tape.
A second magnetic field pattern region at the second end of the symmetric servo mark that is substantially perpendicular to the magnetic tape and away from the magnetic tape.
30. (30), wherein a magnetic field is configured to include a third magnetic field pattern region substantially parallel to the magnetic tape between the first end and the second end. System.
(32)
The system according to (31), wherein each of the first magnetic field pattern region and the second magnetic field pattern region has a direction forming an angle of 45 degrees or more with the magnetic tape.
(33)
31. The system according to (31) or (32), wherein each of the first magnetic field pattern region and the second magnetic field pattern region has a direction forming an angle of 75 degrees or more with the magnetic tape.
(34)
A magnetic field generating circuit configured to apply a current to the write head for the short period of time, wherein the magnetic field generating circuit raises the current to a threshold and then shuts off the current in a short period of time. , The system (35) according to any one of (30) to (33).
The system according to any one of (30) to (34), further comprising a magnetic field generating circuit configured to increase the current and immediately stop the current after the short period of time.
(36)
The system according to any one of (30) to (35), wherein the short period is between about 10 nanoseconds and 50 nanoseconds.
(37)
The write head is configured to apply the magnetic field to the servo track of the magnetic tape having a magnetic bias, and the symmetric servo mark has a mark length between about 0.5 micrometer and 3.0 micrometer. The method (38) according to any one of (30) to (36), which is at least a part of the servo pattern in the servo track having the above.
With the base material
A magnetic layer formed on the substrate and having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%.
A data storage tape provided with a symmetric servo mark recorded on the magnetic layer.
The symmetric servo mark is
With the first remanent magnetization that is substantially perpendicular to the substrate and directed towards the substrate at the first end of the symmetric servo mark.
A data storage tape comprising a second remanent magnetization at a second end of the symmetric servo mark that is substantially perpendicular to the substrate and away from the substrate.
(39)
Servo patterns that include multiple symmetric servo marks and
38. The data storage tape according to (38), further comprising a non-patterned region between the plurality of symmetric servo marks, wherein the non-patterned region has substantially zero residual magnetization.
(40)
The data storage tape according to (38) or (39), wherein the symmetric servo mark comprises a mark length between about 0.5 micrometer and 3.0 micrometer.
(41)
With the base material
A data storage tape provided with a magnetic layer formed on the substrate.
The magnetic layer is
Vertical square ratio greater than 50% and longitudinal square ratio less than 50%,
A data storage tape with residual magnetization in a direction substantially perpendicular to the substrate.
(42)
The data storage tape according to (41), wherein the direction of the residual magnetization that is substantially perpendicular to the substrate forms an angle of at least 45 degrees with the substrate.
(43)
The data storage tape according to (42), wherein the direction of the residual magnetization forms an angle of at least 60 ° with the substrate.
(44)
The residual magnetization comprises a vertical component perpendicular to the substrate and a longitudinal component parallel to the substrate, the longitudinal component being less than 50% larger than the vertical component. The data storage tape according to any one of 41) to (43).
(45)
The data storage tape according to (44), wherein the longitudinal component is less than 25% larger than the vertical component.
(46)
The data storage tape according to any one of (41) to (45), wherein the direction of the residual magnetization is oriented away from the base material or toward the base material.
(47)
A data storage tape provided with at least one servo track of the magnetic layer.
The servo track comprises a plurality of servo marks and non-patterned areas.
The data storage tape according to any one of (41) to (46), wherein the direction of the residual magnetization in the non-patterned region is substantially opposite to the direction of the residual magnetization of the plurality of servo marks.
(48)
A data storage tape further comprising at least one data track in the magnetic layer, wherein the plurality of servo tracks are configured to facilitate positioning of the data head with respect to the at least one data track. The data storage tape according to (47).
(49)
A step of passing a magnetic tape through at least one magnetic field, said magnetic tape comprising a substrate and a magnetic layer having a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%. , Steps and
A method comprising the step of forming a residual magnetization in the magnetic layer in a direction substantially perpendicular to the substrate using at least one magnetic field.
(50)
The method according to (49), wherein the direction of the residual magnetization forms an angle of at least 45 ° with the substrate.
(51)
The step of generating the residual magnetization comprises a step of generating a residual magnetization having a vertical component perpendicular to the substrate and a longitudinal component parallel to the substrate, the longitudinal component being the vertical component. The method according to any of (49) and (50), wherein the vertical component is less than 50% of the component and is oriented away from the substrate or in the direction of the substrate.
(52)
51. The method of (51), wherein the longitudinal component is less than 25% larger than the vertical component.
(53)
The step of passing the magnetic tape through at least one magnetic field is
The step of driving the magnetic tape in the first direction and
The step of passing the magnetic tape through the first magnetic field pattern of the first magnetic head,
The method further comprises the step of passing the magnetic tape through the second magnetic field pattern of the second magnetic head following the first magnetic field pattern, wherein the longitudinal component of the first magnetic field pattern is. The method (54) according to any one of (49) to (52), which is substantially opposite to the longitudinal component of the second magnetic field pattern.
A step of applying the first magnetic field pattern to the magnetic tape from the first surface of the magnetic tape,
The method according to (53), further comprising a step of applying the second magnetic field pattern to the magnetic tape from a second surface opposite to the first surface of the magnetic tape.
(55)
Magnetic tapes containing a vertical square ratio greater than 50% and a longitudinal square ratio less than 50%,
A tape drive configured to run the magnetic tape in the first direction,
A system comprising with at least one magnetic head, wherein the at least one magnetic head is configured to generate remanent magnetization in a direction substantially perpendicular to the magnetic tape.
(56)
The residual magnetization comprises a vertical component perpendicular to the substrate of the magnetic tape and a longitudinal component parallel to the substrate, the longitudinal component having a magnitude less than 50% of the vertical component. The system according to (55).
(57)
56. The system of (56), wherein the longitudinal component is less than 25 percent larger than the vertical component.
(58)
The at least one magnetic head is a first magnetic head configured to apply a first magnetic field pattern to the magnetic tape, and the longitudinal component of the first magnetic field pattern is substantially the first. The first magnetic head, which is in the direction of
A second magnetic head configured to apply a second magnetic field pattern to the magnetic tape after the first magnetic head, wherein the longitudinal component of the second magnetic field pattern is substantially the first. The system according to any one of (55) to (57), comprising a second magnetic head in a second direction opposite to the first direction.
(59)
The first magnetic head is arranged on the first surface of the magnetic tape, and the second magnetic head is arranged on the second surface of the magnetic tape opposite to the first surface. 57) The system according to.
(60)
The at least one magnetic head is configured to generate a residual magnetization as a bias magnetization before writing a plurality of servo marks on the at least one servo track.
The system according to any one of (55) to (59), wherein the plurality of servo marks have a residual magnetization having a second direction different from the first direction of the bias magnetization.
(61)
With the base material
A magnetic layer formed on the substrate and having a vertical square ratio of greater than 50% and a longitudinal square ratio of less than 50%.
The first of the longitudinal planes of the servo track on the magnetic layer and the servo pattern in the servo track, which is in contact with the vertical plane perpendicular to both the base material and the length of the base material and is parallel to the base material. A servo pattern with multiple servo marks, each containing a pattern residual magnetization of the first directional octet placed on the surface of
A non-patterned region of the second directional octet in the servo track that is in contact with the vertical plane and is located on the second plane of the longitudinal plane opposite the first plane. A data storage tape with a non-patterned region with residual magnetization.
(62)
The data storage tape according to (61), wherein the second directional octet is arranged on the same vertical surface side as the first directional octet.
(63)
The data storage tape according to any one of (61) and (62), wherein the second directional octet is arranged opposite the vertical plane as the first directional octet.
(64)
The first directional octet and the second directional octet are each bounded by a plane forming an angle of 60 ° or less with the vertical plane, (61)-(63). The data storage tape according to any one of the above.
(65)
The first directional octet and the second directional octet are each bounded by a plane forming an angle of 45 ° or less with the vertical plane, (61)-(64). The data storage tape according to any one of the above.
(66)
The first directional octet and the second directional octet are each bounded by a plane forming an angle of 30 ° or less with the vertical plane, (61)-(65). The data storage tape according to any one of the above.
(67)
The residual magnetization of the pattern of each of the plurality of servo marks is the first pattern residual magnetization in the first directional octet, the first directional octet, and the second directional eight. The data storage tape according to any one of (61) to (66), comprising a second pattern of remanent magnetization in a third directional eight-quarter circle that is different from both of the minute circles.
(68)
With the base material
A magnetic layer formed on the substrate and having a vertical square ratio of greater than 50% and a longitudinal square ratio of less than 50%.
A servo track on the magnetic layer and a servo pattern in the servo track, which is a vertical plane that is in contact with a longitudinal plane parallel to the substrate and is perpendicular to both the substrate and the length of the substrate. A servo pattern with a plurality of servo marks, each of which has a pattern residual magnetization of the first directional octagonal circle arranged on the first surface, and
A non-patterned region in the servo track that is disposed on the second surface of the vertical surface opposite to the first surface, in contact with the longitudinal surface, and is longitudinal as the first directional octet. A data storage tape with a non-patterned remanent magnetization in a second directional octet placed opposite the direction.
(69)
The data storage tape according to (68), wherein the pattern residual magnetization and the non-pattern residual magnetization have directions substantially parallel to the substrate, respectively.
(70)
The data storage tape according to (69), wherein the direction of the pattern residual magnetization is substantially opposite to the direction of the non-pattern residual magnetization.
(71)
The first directional octet and the second directional octet are each bounded by a surface forming an angle of 60 ° or less with the longitudinal surface, (68)-(70). The data storage tape according to any one of the above.
(72)
The first directional octet and the second directional octet are each bounded by a plane forming an angle of 45 ° or less with the longitudinal plane, (68)-(71). The data storage tape according to any one of the above.
(73)
The first directional octet and the second directional octet are each bounded by a surface forming an angle of 30 ° or less with the longitudinal surface, (68)-(72). The data storage tape according to any one of the above.
(74)
A step of forming a plurality of servo marks on the servo track of the magnetic layer of a magnetic tape, wherein the magnetic layer is formed on a substrate and has a vertical square ratio greater than 50% and a longitudinal square less than 50%. A method with steps, with ratios,
The servo track comprises a non-patterned region with bias magnetization.
The plurality of servo marks are different from the bias magnetization and have a residual magnetization configured to generate a servo signal by a read head configured to identify the plurality of servo marks.
The servo signal is
A waveform having a unipolar pulse when the residual magnetization contains a vertical component opposite to the vertical component of the bias magnetization and the residual magnetization contains the longitudinal component consistent with the longitudinal component of the bias magnetization. When,
A waveform having a bipolar pulse when the residual magnetization has a longitudinal component opposite to the longitudinal component of the bias magnetization.
A method comprising with a waveform having a substantially symmetric bipolar pulse when the bias magnetization has substantially randomized vertical and longitudinal components.
(75)
The waveform having the bipolar pulse is the first portion of the residual magnetization having a vertical component opposite the vertical component of the bias magnetization and the longitudinal component opposite the longitudinal component of the bias magnetization. Corresponds to a second portion of the residual magnetization having a stronger pulse corresponding to, a vertical component corresponding to the vertical component of the bias magnetization, and the longitudinal component opposite to the longitudinal component of the bias magnetization. The method according to (74), comprising a weaker pulse.
(76)
The method according to (74) or (75), wherein the polarity of the waveform is determined by the direction of the vertical component and the longitudinal component of the bias magnetization.
(77)
The method according to any one of (74) to (76), further comprising the step of generating the bias magnetization in the magnetic layer before forming the plurality of servo marks.
(78)
The step of forming the plurality of servo marks includes a step of selecting the position of the magnetic head with respect to the magnetic tape and a step of selecting the direction of the magnetic field pattern generated by the magnetic head (74) to (77). The method described in any one of the above.
(79)
The method according to any one of (74) to (78), wherein the servo signal is not processed from the read head.
(80)
13. The method of any one of (74) to (79), further comprising aligning the readhead to at least one data track on the magnetic tape in response to generating the servo signal. ..

Claims (17)

With the base material
The magnetic layer formed on the first surface side of the base material and
An underlayer formed between the base material and the magnetic layer,
Equipped with
The magnetic layer contains magnetic particles and contains magnetic particles.
The magnetic particles include barium ferrite particles or strontium ferrite particles.
The magnetic layer includes a servo track containing a servo pattern and a non-pattern area.
The servo pattern comprises a plurality of servo marks, each containing a pattern remanent magnetization of a first directional octet.
The non-patterned region has a non-patterned remanent magnetization of the second directional octet.
The first directional octet is located in the region between a vertical plane perpendicular to both the substrate and the length of the substrate and a first surface of a longitudinal plane parallel to the substrate. ,
The second directional octet is a magnetic tape placed in the region between the vertical plane and the second plane of the longitudinal plane. The magnetic tape according to claim 1, wherein the magnetic tape has a vertical square ratio larger than a longitudinal square ratio. The magnetic tape according to claim 1, wherein the substrate comprises a blend or copolymer of polyester, polyethylene terephthalate and polyethylene naphthalate, a polyolefin, a cellulose derivative, a polyamide, a polyimide, and a combination thereof. The magnetic tape according to any one of claims 1 to 3, wherein the second directional octet is arranged on the same vertical surface side as the first directional octet. The magnetic tape according to any one of claims 1 to 3, wherein the second directional eight-quarter circle is arranged on the side of a vertical surface opposite to the first directional eight-quarter circle. Any of claims 1 to 5, wherein the first directional octet and the second directional octet are each bounded by a plane forming an angle of 60 ° or less with the vertical plane. The magnetic tape described in item 1. Any of claims 1 to 6, wherein the first directional octet and the second directional octet are each bounded by a plane forming an angle of 45 ° or less with the vertical plane. The magnetic tape described in item 1. Any of claims 1 to 7, wherein the first directional octet and the second directional octet are each bounded by a plane forming an angle of 30 ° or less with the vertical plane. The magnetic tape described in item 1. The residual magnetization of the pattern of each of the plurality of servo marks is the first pattern residual magnetization in the first directional octet, the first directional octet, and the second directional eight. The magnetic tape according to any one of claims 1 to 8, comprising a second pattern of remanent magnetization in a third directional eight-quarter circle that is different from both of the minute circles. The pattern residual magnetization includes a vertical component perpendicular to the substrate and a longitudinal component parallel to the substrate, the longitudinal component being less than 50% larger than the vertical component. The magnetic tape according to any one of claims 1 to 9. The magnetic tape according to claim 10, wherein the longitudinal component is less than 25% larger than the vertical component. The magnetic tape according to any one of claims 1 to 11, wherein the non-pattern residual magnetization is a magnetic bias in the non-pattern region. The magnetic tape according to any one of claims 1 to 12, wherein each of the plurality of servo marks is arranged alternately with a non-patterned region along the length of the magnetic layer. 13. Magnetic tape. The magnetic tape according to any one of claims 1 to 14, wherein the magnetic layer further includes a data track. The magnetic tape according to any one of claims 1 to 15, wherein the servo pattern has a C shape. The magnetic tape according to any one of claims 1 to 16.
The spool on which the magnetic tape is spooled and
A tape cartridge comprising a cartridge containing the spool.

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