JP2020024776A - Servo writing for magnetic recording medium with perpendicular anisotropy - Google Patents

Abstract

To provide a technique for performing erasing and writing on a magnetic tape and a magnetic recording tape which defines or has a squareness ratio in a perpendicular direction greater than 50% and a squareness ratio in a longitudinal direction less than 50%.SOLUTION: A magnetic tape 280 is biased by residual magnetization or magnetic orientation in an optional direction. One or two head systems use various magnetic field patterns to produce a desired residual magnetization. A servo mark may have a magnetic orientation opposite to a remaining bias on a servo track, for example, a residual magnetization that is substantially perpendicular to the magnetic tape. A write head 290 alternately changes the direction of magnetic field, and continuously biases and writes a servo pattern to the magnetic tape. Additionally, a symmetrical servo mark is formed in the magnetic tape including the write head having a gap width approximately equal to a length of the servo mark.SELECTED DRAWING: Figure 9B

Description

The present disclosure relates to a magnetic medium, and more particularly, to a servo pattern on a magnetic recording medium.

Magnetic data recording media such as magnetic tapes and magnetic disks are commonly used for data storage and retrieval. Magnetic data recording media can be classified as longitudinal or vertical. Most conventional magnetic media are longitudinal. In a longitudinal medium, the maximum magnetic remanent magnetization can be obtained in a direction substantially parallel to the plane of the medium. That is, in the longitudinal medium, the magnetic preferred axis orientation of the individual magnetic domains is parallel or substantially coincident with the surface of the medium and the direction of medium movement. On the other hand, in a perpendicular medium, the maximum remanence of the magnetic particles is possible perpendicular to the plane of the medium. That is, in the perpendicular medium, the magnetic preferred axis orientation of each magnetic domain is mainly perpendicular to the medium surface. However, magnetic media can have particles that can have both a significant longitudinal component and a significant vertical component in their orientation. Perpendicular media generally allows for much higher storage densities than are achieved with longitudinal media.

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

During data storage and restoration, the head must position each data track and follow the path of the data track exactly along the media surface. Servo technology has been developed to facilitate accurate positioning of the transducer head relative to the data tracks. Servo patterns refer to signals or other recorded marks on a medium used for tracking purposes. That is, a servo pattern is recorded on a medium, and a reference point for a data track is provided. The servo read head has a constant displacement relative to the transducer head reading the data tracks. 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 relative to the data track and the lateral distance of the servo read head relative to the transducer head so that the transducer head can effectively read and / or write data to the data track. , Are properly positioned along the data track.

In some data recording media such as magnetic tape, the servo patterns are stored on special tracks on the media called "servo bands." The servo band serves as a reference for the servo controller. A plurality of servo patterns can be defined for a servo band. Some magnetic media include multiple servo bands, with data bands located between the servo bands.

One type of servo pattern is a time-based servo pattern. Time-based servo technology refers to a servo technology that uses non-parallel servo marks and time or distance variables to identify head position. The time offset between the detection of two or more servo marks can be converted to a PES, which defines the lateral distance of the transducer head to the data track. For example, given a constant speed magnetic tape formed with a servo pattern "/ ＼", if the read head is located at the bottom of the pattern "/ ＼", the mark "/" and the mark "＼" The time between detections is longer and shorter if the read head 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 locating the center of the pattern “/ ＼”, a known distance between the center of the servo band and the data track can be specified. Time-based servo patterns are commonly implemented on magnetic tape media, but may be useful on other media as well.

In general, the present disclosure relates to magnetic recording media, such as magnetic tape, and techniques for erasing and writing magnetic storage tapes that define or have a vertical squareness ratio greater than 50% and a longitudinal squareness ratio less than 50%. . Magnetic storage tapes that exhibit greater perpendicular squareness or perpendicular 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 a perpendicular component and a longitudinal component to the orientation. May be oriented. This disclosure describes examples of magnetic tapes that have various magnetic orientations in bias and servo patterns, as well as various techniques for creating such orientations.

For example, the magnetic tape may be biased to define a remanent magnetization having an orientation or direction having a perpendicular component and a longitudinal component. Either the vertical or the longitudinal bias can be generated with two heads located on opposite sides of the magnetic tape or one head adjusted to a specific distance from the magnetic tape. The servo pattern can be written on the magnetic tape with a magnetic orientation opposite to the remaining bias on the servo track, eg, a remanent magnetization substantially perpendicular to the magnetic tape. A bias in one of the eight directional octants, for example, one of the non-zero vertical and longitudinal components, can also be generated with a single head. The servo pattern may be written, or the remanent magnetization of the servo mark may be oriented from the directional octant of the bias magnetization to a generally opposite directional octant.

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 a servo pattern to the magnetic tape. In this continuous writing technique, the write head alternates the direction of the magnetic field so that the trailing edge of the alternating magnetic field creates a bias in the tape or writes a servo mark having a remanent magnetization substantially opposite this bias. It may be.

Magnetic tapes having a larger vertical squareness ratio can also include symmetric servo marks, which can collectively define a servo pattern. The dimension of the gap width of the magnetic head can be set so as to be substantially 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 a magnetic field is applied to the magnetic tape during such a short period, 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 symmetric from one end of the servo mark to the other end of the servo mark.

In one example, the present disclosure includes a substrate and a magnetic layer formed on the substrate, the magnetic layer including a vertical squareness ratio greater than 50% and a longitudinal squareness ratio less than 50%. A data storage tape including a servo track on a magnetic layer is described. The data storage tape also includes a servo pattern in the servo track, the servo pattern including a plurality of servo marks each having a pattern remanent magnetization in a first direction substantially perpendicular to the substrate; A non-patterned area in a servo track immediately adjacent to and between the non-patterned areas substantially perpendicular to the substrate and defining a non-patterned remanent magnetization in a second direction opposite to the first direction. Region.

In another example, the present disclosure is a step of passing a magnetic tape near a magnetic head, wherein the magnetic tape has a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. Generating a first magnetic field in a first direction along a magnetic tape having a magnetic head, including a layer, a servo track, and a data track, and a second magnetic field along the magnetic tape by the magnetic head. And alternately generating a second magnetic field in the direction of.

In a further example, the present disclosure is a tape drive configured to run a magnetic tape, wherein the magnetic tape has a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. Generating a first magnetic field in a first direction along a magnetic tape while the magnetic tape is running near the magnetic head, including a layer, a servo track, and a data track; And a magnetic head configured to alternately generate a second magnetic field in a second direction along the magnetic tape.

In another example, the present disclosure relates to passing a magnetic tape near a write head and generating a short-term magnetic field by the write head to define a symmetric servo mark that defines a mark length approximately equal to a gap width of the write head. On a magnetic tape.

In a further example, the present disclosure provides a tape drive for running a magnetic tape and a symmetric servo mark that generates a magnetic field within a short period of time across the gap width to define a mark length approximately equal to the write head gap width. A write head configured to create on magnetic tape.

In a further example, the present disclosure is directed to a substrate, a magnetic layer formed on the substrate and including a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%; A data storage tape is described that includes a symmetric servo mark. The symmetric servo mark is substantially perpendicular to the substrate at a first end of the symmetric servo mark, has a first remanent magnetization oriented in the direction of the substrate, and a second end of the symmetric servo mark. A second remanent magnetization substantially perpendicular to the substrate and away from the substrate.

In another example, the present disclosure describes a data storage tape that includes a substrate and a magnetic layer formed on the substrate. The magnetic layer includes a perpendicular squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%, and a remanent magnetization 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, the magnetic tape comprising: a substrate having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. And generating a remanent magnetization in the magnetic layer in a direction substantially perpendicular to the substrate using at least one magnetic field.

In a further example, the present disclosure is directed to a magnetic tape that includes a vertical squareness ratio greater than 50% and a longitudinal squareness ratio less than 50%, and a tape drive configured to run the magnetic tape in a first direction. And a system including at least one magnetic head. 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 directed to a magnetic layer formed on a substrate, wherein the magnetic layer comprises a vertical squareness ratio greater than 50% and a longitudinal squareness ratio less than 50%. And a data storage tape including a servo track on a magnetic layer. The data storage tape further includes a servo pattern in the servo track, the servo pattern comprising a plurality of 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 remanent magnetization in a first directional octant disposed on a first one of the longitudinal planes parallel to the substrate, and a first non-patterned area in the servo track that is in contact with the vertical plane; And a non-patterned region having a non-patterned remanent magnetization in a second directional octant disposed on a second surface of the longitudinal surface opposite to the surface.

In a further example, the present disclosure relates to a substrate and a magnetic layer formed on the substrate, the magnetic layer comprising a vertical squareness ratio greater than 50% and a longitudinal squareness ratio less than 50%. , A data storage tape including a servo track on a magnetic layer. The data storage tape further includes a servo pattern in the servo track, wherein the servo pattern comprises a plurality of servo marks, each servo mark tangent to a longitudinal plane parallel to the substrate, the length of the substrate and the length of the substrate. A first directional octant pattern remanent magnetization disposed on a first plane perpendicular to both, a non-patterned area in the servo track, and a first direction Has a non-pattern remanent magnetization in a second directional octant, located on a second side of the vertical plane opposite to the first directional octant.

In a further example, the present disclosure is a method of forming a plurality of servo marks on servo tracks of a magnetic layer of a magnetic tape, wherein the magnetic layer is formed on a substrate and has a vertical squareness ratio of greater than 50% and a 50% squareness. % Of the longitudinal squareness ratio of less than%. The servo track comprises a non-patterned region having a bias magnetization, wherein the plurality of servo marks are different from the bias magnetization and are configured to generate a servo signal by a read head configured to identify the plurality of servo marks. Wherein the servo signal includes a waveform having a unipolar pulse when the remanent magnetization includes a perpendicular component opposite to the perpendicular component of the bias magnetization, and the remnant magnetization includes a longitudinal component of the bias magnetization. A coincident longitudinal component, a waveform having a bipolar pulse when the remanent magnetization has a longitudinal component opposite to the longitudinal component of the bias magnetization, and vertical and longitudinal components in which the bias magnetization is substantially randomized. And a waveform having substantially symmetric bipolar pulses.

FIG. 1 is a schematic cross-sectional view of an exemplary magnetic storage medium.

FIG. 4 is a conceptual diagram of an example of a direction of remanent magnetization in one of eight octants after applying a magnetic field to a magnetic storage tape.

FIG. 3 is a schematic diagram of an exemplary hysteresis curve defining a squareness ratio of a magnetic layer of a magnetic storage medium.

FIG. 2 is a conceptual diagram of an exemplary servo writing system.

FIG. 3 is a conceptual diagram of an exemplary servo pattern in a servo track of a magnetic storage tape.

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

FIG. 4 is a conceptual diagram of an exemplary bias and servo pattern in a longitudinal magnetic orientation. FIG. 5 is a conceptual diagram of an exemplary bias and servo pattern in a longitudinal magnetic orientation and a corresponding readout signal graph.

FIG. 3 is a conceptual diagram of an exemplary bias and servo pattern in a perpendicular magnetic orientation. FIG. 4 is a conceptual diagram of an exemplary bias and servo pattern in a perpendicular magnetic orientation and a corresponding readout signal graph.

FIG. 4 is a diagram showing various directions of residual magnetization of a bias in a magnetic storage tape.

FIG. 7 shows a conceptual diagram of an exemplary magnetic medium including a magnetic bias of directional octant VIII, with a corresponding readout signal graph. FIG. 7 shows a conceptual diagram of an exemplary magnetic medium including a magnetic bias of directional octant VIII, with a corresponding readout signal graph.

FIG. 4 shows a conceptual diagram of an exemplary magnetic media including a directional octant IV magnetic bias, with a corresponding readout signal graph. FIG. 4 shows a conceptual diagram of an exemplary magnetic media including a directional octant IV magnetic bias, with a corresponding readout signal graph.

FIG. 3 shows a conceptual diagram of an exemplary magnetic medium including a magnetic bias of directional octant I, with a corresponding readout signal graph. FIG. 3 shows a conceptual diagram of an exemplary magnetic medium including a magnetic bias of directional octant I, with a corresponding readout signal graph.

FIG. 4 shows a conceptual diagram of an exemplary magnetic medium including a directional octant V magnetic bias, with a corresponding readout signal graph. FIG. 4 shows a conceptual diagram of an exemplary magnetic medium including a directional octant V magnetic bias, with a corresponding readout signal graph.

FIG. 3 shows a conceptual diagram of an exemplary magnetic medium substantially free of magnetic bias from randomized magnetic particles, with a corresponding readout signal graph. FIG. 3 shows a conceptual diagram of an exemplary magnetic medium substantially free of magnetic bias from randomized magnetic particles, with a corresponding readout signal graph.

FIG. 3 is a conceptual diagram of an exemplary magnetic medium including remanent magnetization of a servo mark due to leading and trailing edges of a magnetic field, and a corresponding read signal graph.

FIG. 2 is a conceptual diagram of an exemplary magnetic medium including remanent magnetization of a servo mark by continuously writing a trailing edge of a magnetic field and a corresponding read signal graph.

FIG. 3 is a conceptual diagram of a single magnetic head that writes a servo pattern by alternately changing the direction of a magnetic field. FIG. 3 is a conceptual diagram of a single magnetic head that writes a servo pattern by alternately changing the direction of a magnetic field.

FIG. 4 is a conceptual diagram of a gap width of a magnetic head and a servo mark having a length substantially equal to the gap width. FIG. 4 is a conceptual diagram of a gap width of a magnetic head and a servo mark having a length substantially equal to the gap width.

FIG. 3 is a conceptual diagram of a magnetic head that forms a symmetric servo mark having a magnetic field corresponding to the length of the symmetric servo mark.

FIG. 4 is a timing diagram of a current pulse generating a magnetic field used to form a symmetric servo mark.

FIG. 3 shows a conceptual diagram of a magnetic medium having a symmetric servo mark created on a bias and a corresponding read signal. FIG. 3 shows a conceptual diagram of a magnetic medium having a symmetric servo mark created on a bias and a corresponding read signal.

FIG. 4 is a flow diagram illustrating an exemplary technique for creating a substantially longitudinal or vertical bias on a magnetic tape having a greater vertical squareness ratio.

FIG. 4 is a flow diagram illustrating an exemplary technique for generating a bias in a unidirectional octant and forming a servo mark having a remanent magnetization in a directional octant different from the bias.

FIG. 3 is a flow diagram illustrating an exemplary technique for continuously biasing and writing servo marks by alternating the direction of a magnetic field.

FIG. 2 is a flow diagram illustrating an exemplary technique for forming symmetric servo marks on a magnetic storage tape.

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

As used herein, a larger vertical squareness ratio generally refers to 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 as a vector having a vertical component, for example, perpendicular to the plane of the magnetic tape, and a longitudinal component, for example, parallel to the plane of the magnetic tape. The magnetic particles of a magnetic tape that define a larger vertical squareness ratio (ie, "perpendicular magnetic tape") may have a tendency to be oriented somewhat perpendicular to the magnetic tape, but with a larger vertical squareness. Magnetic particles exhibiting a ratio can be isotropic in some materials used for magnetic tape. In contrast, conventional magnetic storage tapes have magnetic particles that are oriented, if not completely, substantially parallel to the plane of the magnetic storage tape.

An advantage of magnetic storage tapes having a larger vertical squareness ratio is higher data storage capacity. However, a disadvantage of this type of magnetic medium is that magnetic particles allow complex magnetic orientation. These complex orientations can cause unconventional magnetic fields, reduce the signal-to-noise ratio associated with reading marks on magnetic tape, and potentially cause data loss during such reading. is there. Thus, accurate biasing and writing techniques can be used to achieve a greater signal-to-noise ratio for information written on perpendicular magnetic tape. The technique of this disclosure is particularly useful for creating a servo pattern on a magnetic tape located in a servo band typically located between data bands.

In one example, the magnetic tape may be biased, ie, erased, either substantially vertically or longitudinally. This bias can also be described as residual magnetization remaining in the magnetic layer of the tape after applying a magnetic field to the tape. This substantially perpendicular or substantially longitudinal remanent 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 that is oriented in the same direction along the tape to create a substantially longitudinal bias. Conversely, each head applies a magnetic field that is directed in the opposite direction along the tape, creating a substantially vertical bias. That is, a particular magnetic orientation may be created on a perpendicular magnetic tape having different portions of a single magnetic field. In either a vertical bias or a longitudinal bias, a corresponding servo pattern (eg, a plurality of servo marks) can be written on the bias to produce a pattern remanent magnetization substantially opposite the bias.

In another example, the magnetic tape may include a bias or remanent magnetization in one of eight directional octants, for example, a magnetic orientation having a non-zero vertical and longitudinal component. This type of bias may be generated with a single head, depending on the direction of the magnetic field and on which side of the magnetic tape the head is. The servo pattern is generally directional octant generally opposite to that of the bias octant, such that a signal is generated at the interface between the two different directions of the servo pattern remanent magnetization and the non-pattern or bias remanent magnetization. Written.

Biasing and servo writing, such as a method of writing a servo pattern on a servo track of a magnetic tape, can be completed in two different magnetic heads and / or two separate steps, but a single write head requires one step. To generate bias and servo patterns. As the tape passes through the write head, a single write head can continuously bias the magnetic tape and write a 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. Thus, the bias and servo writing can be completed in a single pass of the magnetic tape near the write head.

A magnetic field can also be applied to the perpendicular magnetic tape to create symmetric servo marks, eg, portions of a servo pattern. The dimension of the gap width of the magnetic head or the distance traveled by the magnetic field can be set so as to be substantially 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 occur for a short period, typically between 10 ns and 50 ns. In one example, the short period may be no more than about 30 microseconds. Short periods of time may depend at least in part on the speed at which the magnetic tape passes through the magnetic head; for example, faster tape speeds may require shorter current pulses. As a magnetic field is applied to the magnetic tape during such a short period of time, the resulting magnetic orientation in the magnetic tape over the length of the servo mark may be substantially equivalent to the magnetic field. That is, the magnetic orientation of the created servo mark is substantially symmetric 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. By way of example, magnetic tape 10 may be a magnetic storage medium or tape capable of storing data. The magnetic tape 10 includes a base material 12. Substrate 12 defines a first surface and a second surface opposite the first surface. A non-magnetic underlayer is formed on the first surface of the base material. The underlayer 14 contacts the substrate 12 on one surface and defines a coating surface on the opposite surface. The backing layer 20 can be formed on the second surface of the substrate 12. Further, a magnetic layer 16 is formed on the coating surface defined by the underlayer 14. The magnetic layer 16 defines a recording surface 18. The recording surface 18 may be the outermost surface of the magnetic recording medium 10 or may be the surface that a recording head traverses during a data read or write operation. In addition to one or more data tracks, the magnetic layer 16 may support one or more servo tracks that allow a read / write head to align with the data tracks.

The substrate 12 functions as a support for the magnetic recording medium 10 and can be formed from any appropriate material. For example, the substrate 12 can include glass, plastic, organic resin, metal, and the like. In some cases, substrate 12 can include a polymer film. Any suitable polymer or combination of polymers can be used. The polymer may be selected for chemical compatibility, to impart mechanical or electromagnetic properties to the magnetic recording medium 10, or based on other properties. Polymers such as flexibility, rigidity, electrical resistance, conductivity, etc. 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, And combinations thereof. Further, substrate 12 may include 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 substrate 12. The backing layer 20 can have a controlled surface roughness that affects, for example, the winding and rewinding characteristics of certain types of magnetic recording media, such as magnetic tape. The backing layer 20 can also provide magnetic tape 10 with dimensional stability, for example, by minimizing cupping and hardening of the edges of the magnetic tape 10. In some examples, the backing layer 20 can include components that provide electrical resistivity to the composite magnetic tape 10. For example, the backing layer 20 can include carbon black. The electrically resistive backing layer can improve the electromagnetic properties of the magnetic tape 10. Further, the backing layer 20 may include 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 polyurethane and polyolefin, phenoxy resin, nitrocellulose, polyvinyl chloride, and combinations thereof. Backing layer 20 may include 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 substrate 12. Generally, magnetic layer 16 includes a plurality of magnetic particles included in a 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. The magnetic orientation of the magnetic particles in layer 16 may be generated and maintained. Various components of the composition of the magnetic layer 16 can be combined and applied to an article to form the magnetic layer 16 that defines the recording surface 18.

Generally, magnetic layer 16 includes a plurality of magnetic particles that form a pigment. Different magnetic particles define different shapes, and the shape profile can affect the storage density or quality of the formed magnetic tape. By way of example, the magnetic particles can define needle-like or needle-like, platelet-like, low aspect ratio shapes, or the magnetic particles can even define an amorphous shape. The magnetic layer 16 can include magnetic particles of any suitable shape. For example, the magnetic layer 16 can include acicular particles. Typical acicular particles are ferromagnetic or ferrimagnetic iron oxides, such as gamma-iron oxide (γ-Fe2O3), complex oxides of iron, cobalt and nickel, and various ferrite and metal iron, cobalt or alloy particles. Of particles. However, non-acicular particles may exhibit better packing morphology than acicular particles. For example, if the platelet-shaped particles are oriented perpendicular to the surface of the substrate 12 instead of in the longitudinal direction, the platelet-shaped particles may exhibit a denser packing form than the needle-shaped particles. As another example, low aspect ratio particles do not spontaneously stack on each other and can provide a more uniform magnetic recording surface.

Therefore, the magnetic layer 16 can also include particles such as platelet-shaped particles and low aspect ratio particles. Suitable platelet or low aspect ratio particles include various iron, cobalt, and nickel based alloys, including alloys of iron, cobalt and nickel, and compounds of iron and / or cobalt and nickel with oxygen and / or nitrogen. Particles can be included. In some examples, platelet-like or low aspect ratio particles can include particles that include a hexagonal lattice structure. For example, some ferrites, such as barium ferrite (eg, hexagonal barium ferrite), include a hexagonal lattice structure. Another example of platelet-shaped particles suitable for use in the magnetic tapes of the present disclosure are strontium ferrite particles.

The magnetic tape 10 is just one configuration example of the magnetic tape. Alternatively, other magnetic tapes may not include the backing layer 20 or may include multiple backing layers 20. In some examples, magnetic layer 16 may be directly bonded to substrate 12 without underlayer 14. In another example, the magnetic tape 10 can 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 described that the magnetic layer 16 is formed on the base material 12. The term “formed” includes instances where one or more layers are disposed between the magnetic layer 16 and the substrate 12 or whether the magnetic layer 16 is formed directly on the substrate 12, Alternatively, other examples that are directly bonded 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 additional layers disposed therebetween.

FIG. 2A is a conceptual diagram of an exemplary direction of the remanent 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 a base material 12. The magnetic tape 10 can include an additional backing layer, underlayer or interlayer (e.g., between the magnetic layer 16 and the substrate), as described above with respect to FIG. 12 and a magnetic layer 16 formed on the substrate 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 an applied magnetic field). Further, a plurality of magnetic particles may generally be described in a combination having a remanent magnetization 22. Because some of the magnetic particles may be oriented in a different direction than the general magnetic orientation, the generally described remanence 22 of the magnetic particles will cause the magnetic orientation or magnetic layer 16 May also refer to the collective direction of the magnetic particles within.

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

As shown in the example of FIG. 2A, a portion of the magnetic layer 16, ie, the remanent magnetization 22 of one or more magnetic particles, is aligned at about 25 degrees. This alignment or direction of remanent magnetization 22 is from substrate 12 in the direction of magnetic tape travel indicated by arrow 24. Remanent magnetization 22 may also be described as having both non-zero longitudinal and perpendicular components. In fact, a 25 degree remanence 22 indicates that the longitudinal component is smaller than the vertical component of the vector. Therefore, the remanent magnetization 22 is also within the directional octant I.

The directional octants I, II, III, IV, V, VI, VII and VIII may be used to represent the direction of the remanent magnetization 22. The directional octant describes a vector space in which the remanent magnetization 22 can be directed. Each octant is spatially separated from the magnetic tape 10 by a plane. The longitudinal surface 21 is parallel to the substrate 12 and bisects the magnetic layer 16. The vertical surface 23 is orthogonal to the substrate 12 and bisects a cross section of the magnetic layer 16. That is, the vertical surface 23 is perpendicular to the substrate 12 and the length of the substrate 12. In addition, the oblique planes 25 and 27 further divide the vector space to create octant boundaries. In this way, each of faces 21, 23, 25, and 27 intersect at a common line, creating the boundaries of each of the eight octants described herein. In some examples, the remanent magnetization 22 located on one of the surfaces can be described as being within two octants that touch the surface.

The directional octants may be evenly separated by faces 21, 23, 25, and 27 such that each octant defines an angle of approximately 45 degrees. However, in other examples, the planes can be oriented in different directions such that planes 25 and 27 have an angle of 20-70 degrees with longitudinal plane 21. In one example, faces 25 and 27 each have an angle of 30 degrees with longitudinal face 21 such that octants I, IV, V, and VIII tangent to vertical plane 23 and form an angle of 60 degrees with vertical plane 23. Make In another example, faces 25 and 27 are each oriented with longitudinal faces 21 and 60 degrees so that octants I, IV, V and VIII tangent to and form a 30 degree angle with vertical plane 23. Form an angle.

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

Since the exact degree of remanence 22 may be less important than the general orientation with respect to the substrate 12, some examples use directional octants to account for bias and remanence of servo marks. Can be used. Each directional octant can be centered about a particular angle, for example, 22.5 degrees, for directional octant I, but the directional octant is, as shown in FIG. It need not be centered between any of 21, 23, 25 and 27.

In some examples, the remanent magnetization 22 may be along one of the faces 21, 23, 25, and 27 instead of one of the directional octants. When the remanent magnetization 22 is 90 degrees or 270 degrees, for example, along the surface 21, the remnant magnetization 22 is defined as a longitudinal direction because the direction of the remanent magnetization 22 is parallel to the surface of the base material 12 and the magnetic tape 10. can do. Conversely, since the direction of the remanent magnetization 22 is perpendicular to the plane of the base material 12 and the magnetic tape 10, the remanent magnetization 22 aligned with, for example, 0 degrees or 180 degrees along the axis 23 is considered to be perpendicular. Can be defined.

In another example, the remanent magnetization 22 can be defined as being substantially perpendicular or substantially longitudinal to the surface 23 or 21. The expression “substantially perpendicular” or “substantially longitudinal” refers to the remanent magnetization 22 within a given angle of each surface, since the remanent magnetization 22 may not be exactly aligned with either of the surfaces 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 remanent magnetization 22 may be substantially perpendicular. . The change in remanent magnetization 22 considered substantially perpendicular from plane 23 may generally be less than a 45 degree change from plane 23, for example, between 45 and 135 degrees, or 225 to 315 degrees. Between. The change in remanent magnetization 22 considered substantially longitudinal from surface 21 may generally be less than 45 degrees from surface 21, for example, between 315 degrees and 45 degrees, or between 135 degrees and 225 degrees. Between. However, the substantially perpendicular or substantially longitudinal remanent magnetization 22 of the magnetic layer 16 may more specifically be within 25 degrees of either the surface 21 or 23.

FIG. 2B is a schematic diagram of an exemplary hysteresis curve defining the perpendicularity of the magnetic layer of the magnetic storage medium. An example of an electromagnetic property indicative of deagglomeration of magnetic particles is the magnetic squareness ratio. The term squareness ratio as used herein 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 Oersteds. Can be measured. The residual moment and saturation moment parameters of the magnetic material can be observed on the magnetic hysteresis curve. A hysteresis curve defines how a magnetic material can be magnetically oriented or reoriented in response to application and removal of a magnetic field. In the example of FIG. 2B, the residual moment _mr indicates the magnetization remaining in the magnetic material after saturation in a strong magnetic field, and the saturation moment _ms indicates the magnetization in the magnetic material when saturated. Further, the coercive force H _c refers to the magnetic field intensity applied to the magnetic material after saturation in the opposite direction a strong magnetic field is just enough to reduce the moment m to zero. Figure 2B also be magnetized fully reversed given, shown is normalized by the coercive force H _c, the switching field distribution is a measure of the field strength interval (SFD). The SFD is typically measured as the full width w of the hysteresis curve at half the maximum value of the pulse calculated by differentiating the hysteresis curve with respect to the magnetic field H.

Magnetic squareness ratio, in an exemplary hysteresis curve of FIG. 2B, saturation moment m _s (i.e., m _r / m _s) is identified by the ratio of the residual moments m _r for. In some cases, a higher squareness ratio indicates a smaller aggregation or lamination of magnetic particles than a corresponding magnetic material having a lower squareness ratio. Although FIG. 2B shows the general locations of the different hysteresis parameters, the curves are provided only to illustrate the general squareness case, and the hysteresis plots for certain materials contemplated 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 (eg, a direction parallel to the direction in which the substrate is transported in the web manufacturing process), a direction perpendicular to the recording surface of the magnetic recording medium, or the recording surface of the magnetic recording medium. , A hysteresis curve can be measured in the lateral direction. Further, the squareness 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, a direction perpendicular to the surface of the magnetic recording medium) correlates with a decrease in the squareness ratio in another direction (eg, a direction parallel to the surface of the magnetic recording medium), and The reverse is also true.

The squareness 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 squareness ratio is along the long 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. Thus, this type of squareness ratio may be referred to as a magnetic layer having a longitudinal squareness ratio that is greater than the longitudinal squareness ratio or the vertical squareness ratio. The hysteresis curve can be determined by measuring the magnetic properties of the medium when the medium is oriented in the longitudinal arrangement. Subsequently, the squareness ratio can be calculated based on the determined hysteresis curve.

As described generally herein, the magnetic layer 16 of FIG. 1 can have a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. That is, the magnetic layer 16 can have a greater or greater perpendicular squareness ratio, indicative of a magnetic medium having perpendicular anisotropy. In other examples, the magnetic layer 16 can have a vertical squareness greater than 75% and / or a longitudinal squareness less than 25%. In some examples, the magnetic layer 16 can have a vertical squareness greater than 90% and / or a longitudinal squareness less than 10%. In any of these examples, a perpendicular squareness ratio of greater than 50% allows the remanent magnetization of the magnetic layer 16 to be in a direction substantially perpendicular to the substrate 12.

FIG. 3 is a conceptual diagram showing an example of the servo writing system 26 for writing a pre-recording servo pattern on the magnetic tape 32. The magnetic tape 32 may be an example of the magnetic tape 10 described with reference to FIGS. 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, ie, magnetic heads, for writing a servo pattern on the magnetic tape 32. Controller 30 controls the magnetic field applied by one or more servo heads of servo head module 28. The magnetic tape 32 is supplied from a spool 34 to a spool 36 and passes close to, for example, the servo head module 28, for example. For example, magnetic tape 32 may contact one or more servo heads of servo head module 28 during servo recording.

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

In another example, the servo band portion of the magnetic tape 32 may be randomly magnetized. The random magnetization of the magnetic tape 10 can be a substantially zero bias or erasure generated by an alternating magnetic field from one or more magnetic heads. The controller 30 can cause at least one servo head in the servo head module 28 to 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, a servo head can provide a time-based servo pattern that allows for 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 increment between the detection of a servo mark in the servo pattern and the linearity is converted to a PES calculation (hereinafter, “linear PES calculation”). "). A typical time-based servo pattern is shown in FIG. In another example, the servo head module 28 includes an amplitude-based servo pattern provided to enable the read / write head to be accurately positioned on one or more data tracks in the magnetic tape 32. Or 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 pass the magnetic tape near the servo head module 28. The controller 30, or a different controller, can coordinate the running 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 generation of the magnetic field by the servo head module 28. The system 26 can be configured to run the magnetic tape in either direction past the servo head module 28 or in one direction relative to the servo head module 28.

Although system 26 is described as being used to form a servo pattern having a plurality of servo marks on a magnetic tape, 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. The bias can promote a strong signal-to-noise ratio when transitioning between the bias area in the magnetic tape and the servo pattern. Both the bias pattern and the servo pattern can be characterized by remanence in a particular direction with respect to the magnetic tape, as described in FIG. 2A.

In general, the magnetic head of servo module 28 can generate a magnetic field of any suitable strength suitable to achieve a particular magnetic orientation. Factors that influence the choice of magnetic field strength include, for example, the type of magnetic particles in the magnetic layer, additional types of components in the magnetic layer composition, and the particular equipment used to apply the magnetic field. Can be In some examples, the magnetic field strength is correlated to the squareness of the magnetic layer and may be adjusted to achieve the desired remanent 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 in the magnetic layer of the magnetic tape.

Magnetic fields described herein for forming magnetic biases 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, causing the magnetic particles to rotate within the layer. After controllably rotating, 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 manufacturing a magnetic recording medium by coating a magnetic layer on a moving web, a magnetic field can be applied immediately after the web exits the coating device that applies the magnetic layer. By applying a magnetic field before the magnetic layer begins to settle and begin to dry, the magnetic particles in 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 the magnetic marks (eg, bits of information) available to store data on the formed magnetic recording medium. May be increased.

FIG. 4 is a conceptual diagram showing the data storage tape 40 including the data track 42, the servo track 44, and the servo track 46. Data storage tape 40 may be an example of magnetic tape 10 or 32 of FIGS. As referred to herein, a servo mark is a continuous shape that can be sensed as the read head passes over the media surface. Time-based servo marks are generally, but need not be, straight lines, and in some examples, time-based servo marks can have a zigzag or curved shape. For magnetic tape, servo marks are generally written by a single write gap in a servo head having a single electromagnetic pulse. The term servo mark encompasses servo stripes that are straight and also includes curved servo marks and other shaped servo marks, 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 for the calculation of the PES using time measurements between detection of servo marks in the pattern by the read head. In general, all servo marks in a single servo pattern are written using a single electromagnetic pulse, so a tape speed mismatch during servo writing does not affect the spacing of the servo marks in the servo pattern. As mentioned herein, a servo frame includes at least one servo pattern, but a servo frame often includes more than one servo pattern. As an example, servo track 44 includes servo frames 48A and 48B (collectively, "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 with 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 a servo frame are generally written using the same write gap. These commonly shaped adjacent servo marks of separate servo patterns within a servo frame are referred to herein as bursts. The term burst refers to the signal detected when the head passes over the servo marks that make up the burst. For example, servo function 48A includes bursts 50A and 50B. In some examples, servo marks may overlap as well as servo marks, servo patterns and bursts. For simplicity, FIG. 4 does not show overlapping servo marks, servo patterns, bursts or servo frames.

The servo frames 48 each include two servo patterns, each servo pattern including four servo marks having a single linear mark. For example, the four marks of burst 50A are linear. All of the servo patterns in servo band 44 are written by the same servo write head and are substantially identical. 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 only one servo pattern.

The servo patterns in servo tracks 44 and 46 facilitate positioning of the read or data head relative to data tracks 42 at a known distance from 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 detection of the marks forming each servo pattern. Servo marks 52A and 52B ("mark 52") form a servo pattern within servo frame 14A. The servo marks 52 have shapes that are not identical in that their geometric shapes are different from each other, except that they are simply interchanged in the down-tape direction. For example, as shown in FIG. 4, two linear servo marks at different angles to the cross-tape direction have non-identical geometric shapes. Similarly, two non-linear servo marks having the same general shape at different angles to the cross-tape direction, eg, curved servo marks, have non-identical shapes. In contrast, each servo mark of the burst, eg, the four servo marks of burst 50A, typically has the same shape as the other marks in the burst. As the data storage tape 40 passes the read head located 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 of detection of the first servo mark of the servo pattern 52A and the first servo mark of the servo pattern 52B is shown as "time A" in FIG. From this measurement, the position of the read head within the servo track 46 can be determined since the distance between the servo tracks 52A and 52B varies depending on the lateral position of the read head path. For example, if head path 54B is close to data track 42, time A will be greater. Similarly, if head path 54B is farther from data track 42, time A will be shorter.

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

FIG. 5 is a conceptual diagram of an exemplary data storage system 78 that uses magnetic storage tape 92. Magnetic tape 92 is an example of 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 together 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. Magnetic tape 92 may be spooled on one or more spools 94A and 94B (collectively, "spool 94"). Spool 94 may be contained within a cartridge, but this disclosure is not limited in that respect.

The magnetic tape 92 can include a perpendicular magnetic tape and can include a substrate, an underlayer, a magnetic layer, and other layers. The read / write head 86 is a magnetic head and can be arranged to detect magnetic transitions, ie, changes in the magnetic orientation of magnetic particles within the magnetic layer, on the tape 94. Although the magnetic transition may be detected as a change in the read signal from the change in magnetic orientation, the read / write head 86 may 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, such as by rotating the spools 94A and / or 94B to accurately position the read / write head 86 with respect to the tape 92. As described in FIG. 4, the controller 88 can utilize the detected servo patterns in one or more servo tracks to position the read / write head 86 over the data tracks on the magnetic tape 92. . 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 Macintosh, a computer workstation, a handheld data terminal, a palm computer, a mobile phone, a digital paper, a digital TV, a wireless device, a personal digital assistant, a laptop computer, a desktop computer, a digital camera, and a digital recording device. And the like, and may include a central processing unit for any of a variety of computing devices, including and the like. Computer 80 may interpret the output signals from signal processor 90 as data and perform additional calculations and processes so that the data stored on magnetic tape 92 can be used by computer 80 and / or a user. The information stored on magnetic tape 92 from computer 80 is often a backup copy of the information stored on another storage device (eg, a hard drive) of computer 80.

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

6A and 6B are conceptual illustrations of an exemplary bias in a substantially longitudinal magnetic orientation with servo marks and a corresponding graph of a read signal 136. FIG. The magnetic tapes 100 and 116 are examples of the magnetic tape 10, for example. As shown in FIG. 6A, sequential magnetic heads 110 and 112 located on opposite sides of the magnetic tape 100 are used to create a substantially longitudinal bias on 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 runs in the direction of arrow 114 and passes near the magnetic heads 110 and 112, the magnetic layer 103 has a substantially longitudinal magnetic orientation (or substantially longitudinal residual magnetization). Is formed.

All arrows indicating the magnetic orientation in FIG. 6A are restricted 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 oriented away from the substrate 102, for example, to 0 degrees. Therefore, the arrow in 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, for example, 90 degrees. Thus, the overall magnetic orientation in magnetic layer 103 between heads 110 and 112 is, for example, in directional octant 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 octant I. Conversely, if the magnitude of the longitudinal component is greater than the magnitude of the vertical component, the overall magnetic orientation may be in directional octant II. In this specification, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation or residual magnetization of the magnetic tape.

First, the magnetic tape 100 passes through the head 110 generating the magnetic field 111. The arrows of the magnetic field 111 are shown using vertical and longitudinal components and indicate the general direction of the magnetic field 111. A first portion of the magnetic field 111 applied to the magnetic tape 100 is directed toward the substrate 102. The intermediate portion of the magnetic field 111 is directed along the magnetic tape 100 in the direction of arrow 114. The last part 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 a last effect on the magnetic layer 103, the vertical component portion 106 indicates that the vertical component of the generated magnetic orientation is pointing away from the substrate 102. In addition, the magnetic layer 103 includes a longitudinal component generated by an intermediate portion of the magnetic field 111, shown as a longitudinal component portion 104, and remains in magnetic orientation after the magnetic tape 100 passes through the head 110.

Second, the magnetic tape 100 then passes through a head 112 that generates a magnetic field 113. The arrows of the magnetic field 113 are shown using vertical and longitudinal components and indicate the general direction of the magnetic field 113. A magnetic field 113 is applied to the magnetic tape 100 opposite the magnetic field 111, but the magnetic fields 111 and 113 are directed along the magnetic tape 100 in the same general direction toward the arrow 114. A first portion of the magnetic field 113 applied to the magnetic tape 100 is directed toward the substrate 102. The intermediate portion of the magnetic field 113 is directed along the magnetic tape 100 in the direction of arrow 114. The last part of the magnetic field 113 applied to the magnetic tape 100 is directed away from the substrate 102. Since this last part of the magnetic field 113 also has a last effect on the magnetic layer 103, the vertical component 108 without arrows indicates that the vertical component is substantially zero. The last part 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 running direction of the tape 100, for example, about 90 degrees. Thus, the bias (eg, magnetic orientation or remanence) of magnetic tape 100 after passing through 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 before the magnetic head 110. In other examples, an opposite longitudinal bias can be created by switching the direction of both magnetic fields 111 and 113 or running magnetic tape 100 in the opposite direction to arrow 114. Magnetic fields 111 and 113 are simplified with only vertical or longitudinal components to show the effect on magnetic layer 103. In practice, the magnetic fields 111 and 113 can generally have an arch or horseshoe shape created by the magnetic heads 110 and 112. Thus, the magnetic fields 111 and 113 may, in some examples, have both a vertical and a longitudinal component orientation 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. Although the servo head 134 (an example of a magnetic head) is located on the magnetic layer side of the magnetic tape 116, in other examples, the servo head 134 may be located on the base 102 side. Before the magnetic tape 116 passes near the servo head 134, the magnetic tape 116 has substantially no vertical component as indicated by the vertical component portion 124, as shown by the longitudinal component portion 118. Includes magnetic orientation with only a longitudinal component. When the servo head 134 applies a 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 the residual magnetization changes in a specific region of the magnetic tape 116. The leading edge of the magnetic field 135, that is, the portion of the magnetic field 135 that is directed away from the substrate 102, causes the magnetic particles to be directed away from the substrate 102 and creates a vertical component 126. The trailing edge of the magnetic field 135, that is, the portion of the magnetic field 135 that is oriented away from the substrate 102, causes the magnetic particles to be oriented away from the substrate 102, creating a vertical component 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 running indicated by arrow 114 changes the direction of the longitudinal component as indicated by 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 area is about 90 degrees. For example, because no magnetic field 135 was applied to this region of the magnetic tape 116, the longitudinal component 122 did not change by about 90 degrees, and the vertical component 132 remained unchanged at approximately zero magnitude. Accordingly, the servo marks and the servo patterns that include the servo marks have a magnetic orientation that is substantially opposite to the magnetic orientation of the bias on magnetic tape 116. The remaining bias is also called a non-pattern area of the servo track. In other examples, 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 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 read signal 136 varies 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 magnetic tape 116. In general, a greater amplitude between 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 was small.

7A and 7B are conceptual diagrams of exemplary bias and servo patterns in a perpendicular magnetic orientation and corresponding graphs of the read signal 180. FIG. The magnetic tapes 146 and 164 are examples of the magnetic tape 10, for example. 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, sequential magnetic heads 160 and 162 having magnetic fields 161 and 163 in opposite directions are disposed on opposite sides of magnetic tape 146 and create a substantially vertical bias on magnetic 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. As the magnetic tape 146 is run in the direction of arrow 114 so as to pass near the magnetic heads 160 and 162, a bias having a perpendicular magnetic orientation is created in the magnetic layer 149.

As in FIGS. 6A and 6B, all arrows indicating the magnetic orientation in FIG. 7A are restricted to the vertical and longitudinal components. That is, the arrow in the vertical component portion 154 merely indicates that the vertical component of the magnetic orientation in the magnetic layer 149 is oriented away from the substrate 148, for example, to 0 degrees. Thus, the arrow in the longitudinal component 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 in magnetic layer 149 between heads 160 and 162 is, for example, in octant 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 octant I. Conversely, if the magnitude of the longitudinal component is greater than the magnitude of the vertical component, the overall magnetic orientation may be in directional octant II. In this specification, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation or residual magnetization of the magnetic tape.

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

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

Thus, the bias (eg, magnetic orientation or remanence) of magnetic tape 146 after passing through heads 160 and 162 is substantially perpendicular or oriented to one of octants I or VIII. In some examples, a substantially vertical orientation indicates that a longitudinal component of each of the plurality of magnetic particles is substantially smaller than a vertical component of each 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 magnetic tape 164, the magnetic orientation 174 of at least a portion of the magnetic particles in the servo pattern is oriented substantially in the direction of the substrate, and the magnetic orientation of the magnetic particles in the unpatterned region of the magnetic bias. 176 is oriented substantially away from substrate 148. Alternatively, the magnetic orientation of at least a portion of the magnetic particles in the servo pattern may be oriented substantially away from the substrate 148, and the magnetic orientation of the magnetic particles in the unpatterned region of the magnetic bias is substantially May be oriented in the direction of the substrate 148. In either case, the magnetic orientation of the majority 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 remanent magnetization, eg, the bias or direction of the magnetic orientation 158, is substantially perpendicular to the substrate 148. To be 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 greater than or equal to 45 degrees can be considered substantially vertical.

Alternatively, the remanent 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 magnetic heads 160 and 162 may be switched such that magnetic tape 146 passes near magnetic head 162 before magnetic head 160. In another example, a vertical bias in the opposite direction (eg, toward substrate 148) switches both directions of magnetic fields 161 and 163 such that substrate 148 approaches head 160 instead of head 162. Or by reversing 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. Although the servo head 178 and the magnetic head are located on the magnetic layer side of the magnetic tape 164, in another example, the servo head 178 may be located on the base material 148 side. Before the magnetic tape 164 passes near the servo head 178, the magnetic tape 164 has substantially no longitudinal component as indicated by the longitudinal component portion 166, as shown 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 include different orientations at different locations on the magnetic head 178. With the leading edge of the magnetic field 179, that is, the portion of the magnetic field 179 directed away from the substrate 148, the magnetic particles are directed away from the substrate 102, producing a vertical component 126. However, the trailing edge of the magnetic field 179, ie, the portion of the magnetic field 174 that is directed away from the substrate 148, causes the magnetic particles to be directed toward the substrate 148, as opposed to the vertical component portions 172 and 176, A vertical component 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 having a direction substantially perpendicular to the substrate 148 changes the direction of the vertical component as indicated by the vertical component portion 174. That is, the overall remnant 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 area is about 0 degrees. For example, because no magnetic field 179 was applied to this region of the magnetic tape 164, the vertical component 172 did not change at about 0 degrees and the longitudinal component 170 remained unchanged at approximately zero magnitude. Thus, the servo marks and the servo patterns that include the servo marks have a magnetic orientation that is substantially opposite to the magnetic orientation of the bias on magnetic tape 164. The remaining bias is also called a non-pattern area of the servo track. In other examples, the magnetic field 179 may be applied to the magnetic tape 164 for a longer period of time, for example, a longer pulse, so that the vertical component 174 and the longitudinal component 168 have a longer length. Can cover the magnetic tape 164.

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 read 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 a change in magnetic orientation between the servo mark and the bias of magnetic tape 164. In general, a larger amplitude between 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 was small.

FIG. 8 is an illustration of various magnetic orientations of a bias that may be formed on a portion of a magnetic tape. As shown in FIG. 8, the magnetic tapes 210A, 218A, 226A, and 234A have magnetic bias due to remanent magnetization generated in one of the directional octants I, IV, V, and VIII described in FIG. 2A. 3 shows the non-zero vertical and longitudinal component values of. The remanent magnetization of octants I, IV, V, and VIII can have a perpendicular component that is substantially larger than the corresponding longitudinal component, but if a larger longitudinal component is desired, the octant Remanent magnetization in circles II, III, VI and VII may be created. Magnetic tapes 210B, 218B, 226B, and 234B exhibit an overall magnetic orientation or remanence of a plurality of magnetic particles in the magnetic layer of the magnetic tape. The magnetic tapes 242A and 242B show a random magnetic orientation or minimal remanence of magnetic particles using alternating current. The magnetic tapes 210A, 210B, 218A, 218B, 226A, 226B, 234A, 234B, 242A, 242B are all similar to the magnetic tape 10 and are driven in the left or 90 degree direction as described in FIG. 2A. It is stated that. Any of these biases may be formed on a substantial portion of a magnetic tape, for example, a magnetic tape, before writing one or more servo patterns on the bias.

The magnetic tape 210A includes a base material 212 formed on a magnetic layer having a residual magnetization in the directional octant I. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by a longitudinal component 214 and a vertical component 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. Accordingly, magnetic tape 210B provides a magnetic orientation 254 that includes an arrow indicating that magnetic orientation 254 is directional octant I.

The magnetic tape 218A includes a base material 220 formed on a magnetic layer having a residual magnetization in the directional octant V. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by a longitudinal component 222 and a vertical component 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 toward the substrate 220 or 180 degrees. Accordingly, magnetic tape 218B provides a magnetic orientation 260 that includes an arrow indicating that magnetic orientation 260 is a directional octant V.

The magnetic tape 226A includes a base material 228 formed on a magnetic layer having residual magnetization in the directional octant VIII. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by a longitudinal component 230 and a vertical component 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. Thus, magnetic tape 226B provides a magnetic orientation 266 that includes an arrow indicating that magnetic orientation 266 is directional octant VIII.

The magnetic tape 224A includes a base material 236 formed on a magnetic layer having residual magnetization in the directional octant IV. The magnetic orientation of the magnetic particles in the magnetic layer is indicated by a longitudinal component 238 and a vertical component 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 toward the substrate 236 or 180 degrees. Accordingly, magnetic tape 234B provides a magnetic orientation 272 that includes an arrow indicating that magnetic orientation 272 is directional octant IV.

The magnetic tapes 242A and 242B show a random magnetic orientation of the magnetic particles or substantially zero remanent magnetization using alternating current. The magnetic tape 242A includes a substrate 244 formed on a magnetic layer having a randomized magnetic orientation in two or more directional octants. The longitudinal component 246 and the perpendicular component 248 are shown as shaded regions because there is no overall remanent magnetization of the magnetic layer. Thus, the magnetic tape 242B provides a magnetic orientation 278 that includes arrows 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 magnetic 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 bias of the magnetic tapes 242A and 242B may be used in some examples to write the servo pattern into any desired directional octant.

As shown in FIG. 8, magnetic tapes 210B, 218B, 226B, and 234B have remanent magnetization in a direction substantially perpendicular to the substrate. That is, the remanent magnetization is directed to one of the directional octants I, IV, V or VIII. Thus, the perpendicular component of the remanent magnetization in one of the directional octants I, IV, V or VIII may be larger than the corresponding longitudinal component. In some examples, the vertical component may be 75%, or 90%, than the longitudinal component. Typically, the magnetic bias can be in an octant generally opposite the octant of the remanent magnetization of the servo mark. Thus, for example, a magnetic tape can include a servo bias having a magnetic bias in the directional octant I and a remanent magnetization in the directional octant IV or V.

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

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

A magnetic head 290, eg, a servo write head, is used to form a servo pattern, ie, some servo marks, on a magnetic bias pre-formed on the magnetic tape 280. When the magnetic tape 280 runs 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 indicating the magnetic orientation in FIG. 9A are restricted 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, at 90 degrees. Thus, the arrow in the longitudinal component 282 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is oriented in the same direction as arrow 292, for example, 0 degrees. The overall remanent magnetization in the magnetic layer is the directional octant I in the magnetic bias and the directional octant IV in the servo pattern. In this specification, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation of the magnetic tape and the magnetic field. However, FIG. 9B shows the overall magnetic direction when no longitudinal and vertical components are used.

To form a servo pattern on the magnetic tape 280, the magnetic tape 280 is driven over a magnetic head 290 generating a magnetic field 291. The arrows of the magnetic field 291 are shown using vertical and longitudinal components and indicate the general direction of the magnetic field 291. Generally, magnetic field 291 is in the same direction as the magnetic field used to generate the magnetic bias. A first portion of the magnetic field 291 applied to the magnetic tape 280 is directed toward the magnetic tape 280. The intermediate portion of the magnetic field 291 is directed along the magnetic tape 280 in the direction of arrow 292. The last part 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 a last effect on the magnetic tape 280, the vertical component portion 284 indicates that the vertical component of the magnetic bias is maintained in the directional octant 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 indicated by the vertical component 286. In this way, the vertical component 286 defines the different magnetic orientations of the directional octant IV servo marks. The vertical component 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 read signal 294 changes 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 magnetic tape 280. Pulse 298, eg, a unipolar pulse, indicates a change in magnetic orientation between the directional octant I of the magnetic bias and the directional octant IV of the servo mark.

As shown in FIG. 9B, the overall remanent magnetization of the magnetic tape 280 is shown instead of using the longitudinal and perpendicular components provided in FIG. 9A. That is, the overall remanent magnetization may be similar to a field line or pattern of a magnetic field. Magnetic tape 280 is shown in the magnetic orientation shown on magnetic tape 210B in FIG. The magnetic head 290 generates a magnetic field 307 applied to the magnetic tape 280 when the magnetic tape 280 is driven in the direction of the arrow 292 beyond the magnetic head 290. 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. In general, the magnetic field 307 can be described as having an arch or horseshoe shape.

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

According to FIGS. 9A and 9B, magnetic tape 280 includes a substrate and a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. The servo track of the magnetic layer also includes a servo pattern and a non-pattern area. The servo pattern includes a plurality of servo marks having a pattern remanent magnetization of a directional octant IV in contact with a vertical plane 23 orthogonal to the base material. An unpatterned region, for example, a magnetic bias, includes unpatterned remanent magnetization in directional octant I that also touches vertical plane 23. Octants I and IV are on the same side of vertical plane 23 and octants I and IV are on the opposite side of longitudinal plane 21. That is, the vertical components of octants I and IV are in opposite directions, and the longitudinal components of octants I and IV are in the same direction.

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

10A and 10B show conceptual diagrams of an exemplary magnetic medium including a directional octant V magnetic bias, along with corresponding readout signal graphs. As shown in FIG. 10A, the magnetic tape 314 is an example of the magnetic tape 10. As shown in FIG. 10A, magnetic tape 314 includes one or more servo patterns written to magnetic biases within directional octant V of magnetic tape 218A of FIG. One or more servo patterns are written in directional octants I and IV that are generally opposite the directional octants V of the magnetic bias.

A magnetic head 328, eg, a servo write head, is used to form a servo pattern, ie, a number of servo marks, on a magnetic bias previously formed on the magnetic tape 314. When the magnetic tape 314 is run 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.

As in FIG. 9A, all arrows indicating the magnetic orientation of FIG. 10A are limited to a vertical component and a longitudinal component. The arrow in the vertical component portion 322 only indicates that the vertical component of the magnetic orientation in the magnetic layer is oriented in the direction of the substrate, for example 270 degrees. Thus, the arrow in the longitudinal component portion 316 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is oriented in a direction opposite to arrow 292, for example, 180 degrees. Thus, the overall remanent magnetization in the magnetic layer is the directional octant V in the magnetic bias and the directional octant I in the servo pattern. In this specification, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation of the magnetic tape and the magnetic field. However, FIG. 10B shows the overall magnetic direction when no longitudinal and vertical components are used.

To form a servo pattern on the magnetic tape 314, the magnetic tape 314 is driven over a magnetic head 328 generating a magnetic field 329. The arrows of 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 a direction opposite to the magnetic field used to generate the magnetic bias for the tape 218A. A first portion of the magnetic field 329 applied to the magnetic tape 314 is directed toward the magnetic tape 314. The intermediate portion of magnetic field 329 is directed along magnetic tape 280 in the direction of arrow 292. The last part 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 a 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 octant I. To do so.

When a magnetic field 329 is applied to the magnetic tape 314, the leading edge of the magnetic field 329 maintains a vertical component 326. However, an intermediate portion of magnetic field 329 switches the longitudinal component of portion 318 from arrow 292 opposite longitudinal component portion 320 to arrow 292 of longitudinal component portion 318. In this manner, the vertical component 324 and the longitudinal component 318 define different remanent magnetizations of the servo mark in both directional octants IV and I. The vertical component 322 and the longitudinal component 316 remain on the magnetic tape 314 as part of a 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 read 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 magnetic tape 314. The pulse 334 provides the maximum change in amplitude from the change in magnetic orientation between the directional octant V of the magnetic bias and the directional octant I of the servo mark including the vertical component 324. Pulse 336 indicating a change from longitudinal component 318 to longitudinal component 320, for example, a change in directional octants V and IV, provides a smaller amplitude change than pulse 334. Pulses 334 and 336 may both be described as bipolar pulses.

As shown in FIG. 10B, the overall remanent magnetization of the magnetic tape 314 is shown instead of using the longitudinal and perpendicular components provided in FIG. 10A. Magnetic tape 314 is shown in the magnetic orientation shown on magnetic tape 218B in FIG. The magnetic head 328 generates a magnetic field 347 applied to the magnetic tape 314 when 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. In general, the magnetic field 347 can be described as having an arch or horseshoe shape.

The leading edge of magnetic field 347 generates magnetic orientation 342 in directional octant IV, and the trailing edge of magnetic field 347 generates magnetic orientation 340 in directional octant I. Thus, the entire servo mark formed by the magnetic field has a residual magnetization in an octant 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 directional octants V. Thus, the servo marks include a magnetic orientation in directional octant I opposite to the directional octant (ie, directional octant V) of the magnetic bias, and a magnetic orientation in directional octant IV. Further, the servo mark shown in FIG. 10B has a first magnetic orientation of the directional octant I and a third directional octant V different from the directional octant V of the bias or non-pattern area, for example, It may be described as having a second magnetic orientation of directional octant IV. Thus, a servo mark can include magnetic orientation or remanence in more than one directional octant. As expected, read signal 348 is similar to read signal 330 of FIG. 10A. The read signal 348 includes an amplitude 350 and pulses 352 and 354 (both including bipolar pulses) corresponding to a change in the directional octant between the magnetic bias and the servo mark.

According to FIGS. 10A and 10B, magnetic tape 314 includes a substrate and a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. The servo track of the magnetic layer also includes a servo pattern and a non-pattern area. The servo pattern includes a plurality of servo marks having a pattern remanent magnetization of a directional octant I contacting a vertical plane 23 orthogonal to the substrate. Non-patterned regions, eg, magnetic biases, include non-patterned remanent magnetization in directional octant V that also touches vertical plane 23. Octants I and V are on opposite sides of vertical plane 23 and octants I and IV are on opposite sides of longitudinal plane 21. That is, the vertical components of octants I and V are in opposite directions, and the longitudinal components of octants I and V are in opposite directions.

The remanent magnetization in octants I and V may be configured to generate a read signal 348 (eg, a servo signal) having a read head to identify each of the servo marks. If the remanent magnetization of the magnetic tape 314 has a perpendicular component opposite to the perpendicular component of the bias magnetization and the remanent magnetization has a longitudinal component that is also opposite to the longitudinal component of the bias magnetization, the signal 348 is substantially In particular, an amplitude 350 (eg, a waveform) having unipolar pulses 352 and 354 can be included. The stronger pulse 352 includes a vertical component opposite the vertical component of the bias magnetization (eg, vertical component portions 322 and 324) and a longitudinal component opposite the longitudinal component of the bias magnetization (eg, the longitudinal component portion). 316 and 318). The weaker pulse 354 includes a vertical component that matches the vertical component of the bias magnetization (eg, vertical component portion 326) and a longitudinal component opposite to the longitudinal component of the bias magnetization (eg, longitudinal component portion 318 and 320). Pulses 352 and 354 may both be described as bipolar pulses.

11A and 11B show conceptual diagrams of an exemplary magnetic media including a directional octant VIII magnetic bias, along with corresponding readout signal graphs. As shown in FIG. 11A, the magnetic tape 356 is an example of the magnetic tape 10. As shown in FIG. 11A, magnetic tape 356 includes one or more servo patterns written to magnetic biases in directional octant VIII of magnetic tape 226A of FIG. One or more servo patterns are written in directional octants I and IV, generally opposite directional octants VIII of the magnetic bias.

A magnetic head 372, eg, a servo write head, is used to form a servo pattern, ie, some servo marks, on a magnetic bias pre-formed on the magnetic tape 356. When the magnetic tape 356 is run 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.

As in FIG. 9A, in FIG. 11A, all arrows indicating remanent 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, for example, at 90 degrees. Thus, the arrow in the longitudinal component portion 358 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is oriented in a direction opposite to arrow 292, for example, 180 degrees. Thus, the overall magnetic orientation in the magnetic layer is directional octants VIII in the magnetic bias and directional octants I and IV in the servo pattern. In this specification, the perpendicular and longitudinal components of the magnetic orientation are separated to more clearly describe the remanent magnetization of the magnetic tape and the magnetic field. However, FIG. 11B shows the overall magnetic direction when no longitudinal and vertical components are used.

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 of 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 a direction opposite to the magnetic field used to generate the magnetic bias for the tape 226A. A first portion of the magnetic field 373 applied to the magnetic tape 356 is directed toward the magnetic tape 356. An intermediate portion of the magnetic field 373 is directed along arrow 292 along magnetic tape 356. The last part 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 a last effect on the magnetic tape 356, the vertical component portion 366 indicates that the vertical component of the magnetic orientation remains unchanged from the magnetic bias.

When a magnetic field 373 is applied to the magnetic tape 356, the leading edge of the magnetic field 373 changes the vertical component 370 from the vertical component 370 of the magnetic bias. However, the intermediate portion of magnetic field 373 switches the longitudinal component of portion 360 from arrow 292 opposite longitudinal component portion 362 to arrow 292 of longitudinal component portion 360. In this way, vertical component 368 and longitudinal component 360 define different magnetic orientations of the servo marks in both directional octants IV and I. The vertical component 364 and the longitudinal component 358 remain on the magnetic tape 356 as part of a 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 read 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 magnetic tape 356. Pulse 378 provides a change in amplitude from a change in magnetic orientation between directional octant VIII of the magnetic bias and a generally opposite directional octant I of the servo mark including longitudinal component 360. Pulse 380 indicates a greater change from longitudinal component 362 to longitudinal component 360 and from vertical component 360 to vertical component 368, eg, opposite directional octants VIII and IV. Pulses 378 and 380 may both be described as bipolar pulses.

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

The leading edge of the magnetic field 391 creates a magnetic orientation 386 in the directional octant IV, and the trailing edge of the magnetic field 391 creates a magnetic orientation 384 in the directional octant I. Thus, the entire servo mark formed by the magnetic field has a residual magnetization in an octant different from that of the magnetic bias. Since portions of magnetic tape 356 are not affected by magnetic field 391, magnetic orientations 382 and 388 remain directional octant VIII. Thus, the servo mark includes a directional octant I that is generally opposite the directional octant of the magnetic bias (ie, directional octant VIII) and a directional octant of the magnetic bias (ie, directional octant VIII). It contains the remanent magnetization of the directional octant IV, which is exactly the opposite of the octant VIII). That is, the servo mark shown in FIG. 11B has a first magnetic orientation of the directional octant IV and a third directional octant VIII different from the directional octant VIII of the bias or non-pattern region, for example, It may be described as having a second magnetic orientation of the directional octant I. Thus, a servo mark can include magnetic orientation or remanence in more than one directional octant. As expected, read signal 392 is similar to read signal 374 of FIG. 11A. The read signal 392 includes an amplitude 394 and pulses 396 and 398 (both including bipolar pulses) corresponding to a change in the directional octant between the magnetic bias and the servo mark.

According to FIGS. 11A and 11B, magnetic tape 356 includes a substrate and a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. The servo track of the magnetic layer also includes a servo pattern and a non-pattern area. The servo pattern includes a plurality of servo marks having a pattern remanent magnetization of a directional octant IV in contact with a vertical plane 23 orthogonal to the base material. The non-patterned region, eg, the magnetic bias, includes the non-patterned remanent magnetization of the directional octant VIII that also touches the vertical plane 23. Octants IV and VIII are on opposite sides of vertical plane 23, and octants IV and VIII are on opposite sides of longitudinal plane 21. That is, the vertical components of octants IV and VIII are in opposite directions, and the longitudinal components of octants IV and VIII are in opposite directions.

The remanent magnetization in octants IV and VIII may be configured to generate a read signal 392 (eg, a servo signal) having a read head to identify each of the servo marks. If the remanent magnetization of the magnetic tape 356 has a perpendicular component opposite the perpendicular component of the bias magnetization and the remanent magnetization has a longitudinal component that is also opposite to the longitudinal component of the bias magnetization, the signal 392 will be substantially An amplitude 394 (e.g., a waveform) having unipolar pulses 396 and 398 may be included. The stronger pulse 398 has a vertical component opposite the vertical component of the bias magnetization (eg, vertical component portions 368 and 370) and a longitudinal component opposite the longitudinal component of the bias magnetization (eg, the longitudinal component portion). 360 and 362). The weaker pulse 396 has a vertical component that matches the vertical component of the bias magnetization (eg, vertical component portions 364 and 366) and a longitudinal component opposite to the longitudinal component of the bias magnetization (eg, the longitudinal component portion). 358 and 360). Pulses 396 and 398 may both be described as bipolar pulses.

12A and 12B show conceptual diagrams of an exemplary magnetic media including a directional octant IV magnetic bias, along with corresponding readout signal graphs. As shown in FIG. 12A, the magnetic tape 400 is an example of the magnetic tape 10. As shown in FIG. 12A, magnetic tape 400 includes one or more servo patterns written to magnetic biases in directional octant IV of magnetic tape 234A of FIG. One or more servo patterns are written in a directional octant I that is generally opposite the directional octant IV of the magnetic bias.

A magnetic head 410, for example, a servo write head, is used to form a servo pattern, ie, some servo marks, on a magnetic bias pre-formed on the magnetic tape 400. When the magnetic tape 400 is run or driven in the direction of arrow 292 to pass near the magnetic head 410, a servo mark is formed in the magnetic layer of the magnetic tape 400.

As in 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 remanent magnetization in the magnetic layer is oriented in the direction of the substrate, for example 270 degrees. Thus, the arrow in the longitudinal component 402 indicates that the longitudinal component of the remanent magnetization in the magnetic layer is oriented in the same direction as arrow 292, for example, 0 degrees. Thus, the overall magnetic orientation in the magnetic layer is the directional octant IV in the magnetic bias and the directional octant I in the servo pattern. In this specification, the vertical and longitudinal components of the magnetic orientation are separated to more clearly describe the magnetic orientation of the magnetic tape and the magnetic field. However, FIG. 12B shows the direction of the overall remanent magnetization when the longitudinal and perpendicular components are not used.

To form a servo pattern on the magnetic tape 400, the magnetic tape 400 is driven over a magnetic head 410 that is generating a magnetic field 411. The arrows of the magnetic field 411 are shown using the vertical and longitudinal components and indicate the general direction of the magnetic field 411. Magnetic field 411 may be generated in the same direction as the magnetic field used to generate the magnetic bias for tape 234A. A first portion of the magnetic field 411 applied to the magnetic tape 400 is directed toward 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 part 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 a last effect on the magnetic tape 356, the vertical component portion 406 is such that the vertical component of the magnetic orientation is changed from the magnetic bias shown in the vertical component portions 408 and 404. It indicates that.

When a magnetic field 411 is applied to the magnetic tape 400, the leading edge of the magnetic field 411 changes the vertical component 408 from the vertical component 408 of the magnetic bias. The intermediate portion of the magnetic field 411 remains aligned with the longitudinal direction as indicated by the longitudinal component 402 in the same direction as the arrow 292. In this manner, the vertical component 406 defines a different magnetic orientation of the servo mark in the directional octant I adjacent to the directional octant 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 read signal 412 changes 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 magnetic tape 400. Pulse 416 (eg, a unipolar pulse) is derived from the change in remanent magnetization between the directional octant IV of the magnetic bias and the generally opposite directional octant I of the servo mark including the vertical component 406. Provides a change in amplitude.

As shown in FIG. 12B, the overall remanent magnetization of the magnetic tape 400 is shown instead of using the longitudinal and perpendicular components provided in FIG. 12A. Magnetic tape 400 is shown in the magnetic orientation shown on magnetic tape 234B in FIG. The magnetic head 410 generates a magnetic field 425 applied to the magnetic tape 400 when 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 different from the magnetic field used to generate the magnetic bias. In general, the magnetic field 425 can be described as having an arch or horseshoe shape.

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

According to FIGS. 12A and 12B, a magnetic tape 400 includes a substrate and a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. The servo track of the magnetic layer also includes a servo pattern and a non-pattern area. The servo pattern includes a plurality of servo marks having a pattern remanent magnetization of a directional octant I contacting a vertical plane 23 orthogonal to the substrate. An unpatterned region, for example, a magnetic bias, includes a non-patterned remanent magnetization of a directional octant IV that also contacts the vertical plane 23. Octants I and IV are on the same side of vertical plane 23, while octants I and IV are on the opposite side of longitudinal plane 21. That is, the vertical components of octants I and IV are in opposite directions, and the longitudinal components of octants I and IV are in the same direction.

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

FIGS. 13A and 13B show conceptual diagrams of an exemplary magnetic medium including random directional octant magnetic biases, along with corresponding readout signal graphs. 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 directional octants I and IV in a randomized bias or unwritten area. A randomized magnetic bias may have an overall remnant magnetization of substantially zero.

A magnetic head 450, such as a servo write head, is used to form a servo pattern, ie, a number of servo marks, on a randomized magnetic bias pre-formed on the magnetic tape 432. The random magnetic bias can be generated using alternating current or other techniques to reject identifiable signals from the magnetic layer of the magnetic tape 432. When the magnetic tape 432 is run or driven in the direction of arrow 292 to pass near the magnetic head 450, a servo mark is formed in the magnetic layer of the magnetic tape 432.

As with 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, for example, at 90 degrees. Thus, the arrow in the longitudinal component portion 436 indicates that the longitudinal component of the magnetic orientation in the magnetic layer is oriented in the same direction as arrow 292, for example, 0 degrees. Since these hatched portions of the magnetic 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. Absent. Thus, there is no overall remanence in the magnetic bias, but the servo pattern can include a magnetic orientation in the directional octants I and IV. FIG. 13B shows the direction of the overall magnetic orientation without using the longitudinal and vertical components.

To form a servo pattern on the magnetic tape 432, the magnetic tape 432 is driven over a magnetic head 450 that is generating a magnetic field 451. The arrows of the magnetic field 451 are shown using vertical and longitudinal components and indicate the general direction of the magnetic field 451. The magnetic field 451 is generated in a single direction, as opposed to the alternating magnetic field used to generate the random bias of the tape 242A. A first portion of the magnetic field 451 applied to the magnetic tape 432 is directed toward the magnetic tape 432. An intermediate portion of the magnetic field 451 is directed along the magnetic tape 432 in the direction of the arrow 292. The last part 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 a last effect on the magnetic tape 432, the vertical component 442 is such that the vertical component of the magnetic orientation varies from the random magnetic bias shown in the vertical component 444 and 448. Is shown.

When a magnetic field 451 is applied to the magnetic tape 432, the leading edge of the magnetic field 451 changes the vertical component 446 from the vertical component 448 of the random magnetic bias. The middle portion of the magnetic field 451 also causes the longitudinal component 436 to change from the random bias of the longitudinal component 438 in the same direction as the arrow 292. In this way, vertical component portions 446 and 442 and longitudinal component portion 436 define different remanent magnetizations of the servo marks in directional octants 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 in 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 read signal 452 varies as the magnetic orientation of the particles in the magnetic layer changes between a random magnetic bias and different directional octants of the servo mark over the length of the magnetic tape 432. Pulse 456 provides a change in amplitude from a random orientation to directional octant I, and pulse 458 provides a change in amplitude from a random orientation to directional octant IV. Pulses 456 and 458 can be described as being bipolar pulses or substantially symmetric bipolar pulses.

As shown in FIG. 13B, the overall magnetic orientation of the magnetic tape 432 is shown instead of using the longitudinal and vertical components provided in FIG. 13A. Magnetic tape 432 is shown in the magnetic orientation shown on magnetic tape 242B in FIG. The magnetic head 450 generates a magnetic field 471 applied to the magnetic tape 432 when the magnetic tape 432 is driven beyond 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. In general, the magnetic field 471 can be described as having an arch or horseshoe shape.

The leading edge of the magnetic field 471 generates a magnetic orientation 466 in a directional octant IV from the randomized magnetic orientation 468. The trailing edge of the magnetic field 471 creates a magnetic orientation 462 in the directional octant I. The middle of the magnetic field 471 produces a substantially longitudinal orientation 464. Thus, the entire servo mark generated by the magnetic field 471 has a magnetic orientation in a directional octant different from that of the randomized magnetic bias. The magnetic orientations 468 and 460 are randomized by the magnetic field 471 and remain unchanged. Thus, the servo marks include a magnetic orientation in the directional octants I and IV. As expected, read signal 472 is similar to read signal 452 of FIG. 13A. The read signal 472 includes an amplitude 474 and pulses 476 and 478 corresponding to a change in the directional octant between the randomized magnetic bias and the written servo mark. Pulses 476 and 478 can be described as being bipolar pulses or substantially symmetric bipolar pulses. Bipolar pulses may be completely symmetric, but in general, bipolar pulses may be substantially symmetric when pulses 476 and 478 have roughly similar (but opposite) amplitudes and similar widths. .

13A and 13B, the magnetic tape 432 includes a substrate and a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. The servo track of the magnetic layer also includes a servo pattern and a non-pattern area. The servo pattern includes a plurality of servo marks having pattern remanence in directional octants I and IV. However, non-patterned regions, eg, magnetic biases, contain non-patterned remanent magnetization that is substantially zero. This minimum remanent 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, signal 472 may include an amplitude 474 (eg, a waveform) having substantially symmetric counter pulses 476 and 478. However, servo patterns having different directional octants may produce slightly different pulse shapes. As described above, pulses 476 and 478 can be collectively described as bipolar pulses. The bipolar pulse may be substantially symmetric.

As with any of the servo signals of FIGS. 9A-13B, the illustrated servo signals are not processed from the read head. That is, the signal detected from the remanent magnetization of the magnetic tape may be substantially equivalent to the illustrated exemplary waveform. In post-processing, similar types of waveforms or pulses can be reproduced from the magnetic tape with any remanent magnetization, but any of these processes other than amplification will detect similar waveforms from the above-described remanent magnetization in the magnetic tape do not have to.

9A-13B are generally described with respect to the remanent magnetization in a direction substantially perpendicular to the substrate, but the bias and servo marks are not affected by the remanent magnetization having a direction substantially parallel to the substrate. It may be formed. For example, a magnetic tape may include a substrate and a magnetic layer having a vertical squareness ratio greater than 50% and a longitudinal squareness ratio less than 50%. The tape may also include servo tracks of the magnetic layer and non-patterned areas. The servo pattern includes a plurality of servo marks having pattern residual magnetization in the directional octant II. However, non-patterned regions, eg, magnetic biases, include non-patterned remanent magnetization in the directional octant VI. In this way, the servo marks and non-patterned regions may have opposite but substantially longitudinal remanence. Other combinations of servo marks and non-patterned regions having directional octants having substantially longitudinal and opposite remanent magnetization may include octants VI and II, III and VII, and VII and III, respectively. Good.

FIG. 14 is a conceptual diagram of an exemplary magnetic medium that includes a magnetic orientation of magnetic particles in a servo mark due to leading and trailing edges of a magnetic field and a corresponding readout signal graph. As shown in FIG. 14, magnetic tape 480 includes magnetic layers formed on a substrate 482, shown as magnetic orientations 484, 486, and 488. Magnetic orientations 484 and 488 indicate the remanent magnetization of the magnetic bias in unpatterned areas of the servo track, and are substantially perpendicular to substrate 482. However, in other examples, the magnetic orientations 484 and 488 may be defined within a directional octant, such as directional octant V. The magnetic bias for magnetic orientation 484 was generated before the servo marks for magnetic orientation 486. That is, the servo mark and the servo pattern are separated by the non-pattern area of the magnetic bias. Although servo marks are described herein, in other examples, various regions or marks of magnetic orientation can be used to store data on a data track (eg, a magnetic orientation of “1”). Or a 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 over the head 490 in the direction of the arrow 494, the magnetic orientation 486 is created by applying a magnetic field 492 generated from the servo magnetic head 490 to the magnetic tape 480. The leading edge of magnetic field 492 is in a direction toward substrate 482 and the trailing edge of magnetic field 492 is in a direction away from 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 running of the magnetic tape 480 with the Pi distance and the gap length G of the magnetic field 492 during the pulse. Is done.

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

The read signal 496 shows the amplitude 498 created by the interface between the changing magnetic orientations on the magnetic tape 480. The pulse 500 shows a strong increase in amplitude due to the opposite and substantially perpendicular 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. Plateau 502 can provide a relatively weak signal-to-noise ratio for the servo marks formed by magnetic field 492.

The various magnetic orientations herein are generally described as forming magnetic biases or servo marks (eg, some servo marks form a servo pattern). Thus, magnetic biases and servo marks can be recorded as magnetic transitions along the magnetic tape. However, in other examples, the information of a bit (eg, “1” or “0”) can be defined using a mark that includes a certain magnetic orientation. The magnetic transition between the marks can then be used to indicate information stored on the magnetic tape. Thus, 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 corresponding read signal graph. As shown in FIG. 15, the servo magnetic head 490 and the magnetic field 492 of FIG. 14 are used to form a 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 a direction opposite to the magnetic orientation 510 of the servo mark.

Magnetic tape 504 includes magnetic layers formed on substrate 506, shown as magnetic orientations 508, 510, and 512. The magnetic tape may be similar to the magnetic tape 10. Magnetic orientations 508 and 512 indicate magnetic bias in unpatterned areas of the servo track and are substantially perpendicular to substrate 506. However, in other examples, the magnetic orientations 508 and 512 may be defined within a directional octant, such as directional octant 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. Servo marks and servo patterns on magnetic tape 504 are separated by non-patterned regions of magnetic bias.

The magnetic orientation 510 indicates the magnetic orientation of one servo mark in the servo pattern. As the magnetic tape 504 runs past the head 490 in the direction of the arrow 494, the magnetic orientation 510 is created 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 mark. That is, the magnetic field 492 is applied to the magnetic tape 504 during the current pulses in the head 490 over the entire length P ₂ of the servo marks. The gap length G extends to the non-servo mark area (non-pattern area) of the magnetic tape 504, but the magnetic head 490 switches the magnetic field 492 such that the new trailing edge is aligned with the magnetic bias direction magnetic orientation 512. Or flip.

With this alternating magnetic field technique, the trailing edge of the magnetic field 492 forms an entire servo mark having a magnetic orientation 510 substantially perpendicular to the substrate 506 and magnetic orientations 508 and 512 opposite the magnetic bias. . That is, the remanent magnetization of the magnetic field 510 is in the direction in the directional octant I and opposite to the magnetic bias of the directional octant V. Thus, before and after the servo mark along the length of the magnetic tape 504, the magnetic bias in the magnetic orientations 508 and 512 is immediately adjacent to the remanent magnetization of the servo mark in the magnetic orientation 510. Also, the transition between the magnetic orientations 508 and 512 of the unpatterned area and the magnetic orientation 510 of the servo pattern includes only two directions of remanent magnetization, for example, two opposite octants. In the example of magnetic tape 504, the transition includes an orientation substantially perpendicular to substrate 506, in a direction toward and away from the substrate.

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

FIGS. 16A and 16B are conceptual diagrams of a single magnetic head that writes a servo pattern by alternately changing the direction of a magnetic field. The magnetic tape 522 may be similar to the magnetic tape 504 described with reference to FIG. In general, as the magnetic tape 522 passes near the magnetic head 534, the magnetic head 534 is stationary and generates alternating magnetic fields 536A and 536B (collectively, "magnetic field 536"). Due to the alternation of the magnetic field 536, a magnetic bias (for example, a non-pattern area) can be continuously generated using the servo mark 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 area of the magnetic tape 522.

As the magnetic tape 522 travels in the direction of arrow 538 past the magnetic head 534, one of the magnetic fields 536 is applied to the magnetic tape 522. As shown in FIG. 16A, a magnetic bias having a magnetic orientation 526, eg, remanent magnetization, has already been formed on magnetic tape 522. The direction of the magnetic orientation 526 is substantially perpendicular to the substrate 524 and is facing the substrate. After the magnetic orientation 526 was formed, the magnetic head 534 switched to the magnetic field 536A. Magnetic field 536A is generally directed along the length of magnetic tape 522 in the same direction as arrow 538. Field 536A is generated as the trailing edge of the magnetic field 536A is applied to the magnetic tape 522 for a length P _3. P ₃ also corresponds to the current pulses used to generate a magnetic field 536A. Thus, a magnetic orientation 528 of the servo mark is created between transitions A and B.

Before the magnetic head 534 alternates with a magnetic field having a different direction, the magnetic field 536A creates a magnetic orientation 530 that mimics the changing orientation of the magnetic field 536A. The remaining portion of the magnetic tape 522 shown in FIG. 16A is not affected by the magnetic field from the magnetic head 534. Accordingly, the magnetic orientation 532 can include various random magnetic orientations of the magnetic particles. In other examples, the magnetic orientation 532 may have some uniformity in the magnetic direction from the configuration of the magnetic tape 522.

When the transition B of the continuously running 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 is The direction is alternately switched from the direction of the magnetic field 536A to the direction of the magnetic field 536B. As shown in FIG. 16B, The magnetic head 534 is When the trailing edge of the magnetic field reaches transition B, A magnetic field 536B is generated. The magnetic field 536B is For example, as controlled by the controller 30 of the servo writing system 26 of FIG. It may be generated by a current that switches directions. In some examples, Over the time required to create the desired length of servo marks and non-pattern bias areas on the magnetic tape 522, The current is Modulated, Alternatively, it may be a controlled alternating current.

Field 536B may be applied to the magnetic tape 522 across the length P _4, magnetic bias, for example, to form the magnetic orientation 540 of the non-pattern region. P ₄ also corresponds to the current pulses used to generate a magnetic field 536B. Magnetic orientation 540 extends along the length of magnetic tape 522 between transition B and transition C. After 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 magnetic orientation 530 in FIG. 16A, magnetic orientation 542 mimics the direction of magnetic field 536B until the trailing edge of magnetic field 536A changes orientation.

The magnetic tape 522 includes a magnetic bias, eg, a non-patterned area, immediately adjacent to the servo mark. In this way, transitions A, B, and C have a substantially vertical orientation toward substrate 524 and an opposite substantially vertical orientation away from substrate 524. Continuously writing magnetic biases and servo patterns with alternating magnetic fields can allow for a greater signal-to-noise ratio in servo tracks of perpendicular media. In addition, writing the servo patterns and biases in one continuous step reduces the amount of time required and creates the necessary number of systems to produce magnetic tape and user-capable tape.

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, magnetic head 544 includes a gap formed by gap ends 546 and 548. The distance between gap ends 546 and 548 is gap width W. The magnetic field used to bias the magnetic tape and write servo patterns and data is generated between 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 for a pulse that is timed so as to be applied to a magnetic tape having a gap width of about 0.7 μm. The gap width W and the resulting running of the magnetic tape result in an overall mark length of about 2.1 μm.

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

As shown in FIG. 18B, a side cross-sectional view of the magnetic tape 550 includes servo marks 552A to 552C (collectively referred to as “servo marks 552”) and 553A to 553A (collectively referred to as non-pattern areas 553). The magnetic tape 550 is passed near the magnetic head 544, and can form the 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, for example, during an instantaneous 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 becomes substantially equal to the gap width W. As shown in the example of FIG. 18B, each of the servo marks 552 (eg, a region of the magnetic tape 550) is separated by a non-pattern region 553 (eg, a bias remaining in the space between the servo marks 552). . In other examples, servo marks 552 and / or non-patterned areas 553 may indicate data, for example, magnetic head 544 may use a magnetic field to replace servo marks 552 with data tracks on magnetic tape 550. Data marks can be formed.

Short current pulses can occur for short periods of time, typically between 10 and 50 nanoseconds. In one example, the short period may be no more than about 30 microseconds. Short periods of time may depend at least in part on the speed at which the magnetic tape passes through the magnetic head; for example, faster tape speeds may require shorter current pulses. In general, the mark length B and gap width W may be equal to about 2.1 μm. Other example dimensions, such as a mark length of about 1.0 μm, are also contemplated. For example, the gap between the mark lengths B and W is typically between about 0.1 μm and 20 μm. More specifically, the length B of the mark may be between about 0.5 μm and 3.0 μm. Arbitrary dimensions may be possible as long as the mark length B and gap width W are approximately equal.

FIG. 18A is a conceptual diagram of a magnetic head 564 that forms a symmetric servo mark 561 formed by a magnetic field 566 that matches the mark length B of the symmetric servo mark 561. As shown in FIG. 18A, the symmetric servo marks 561 are generated by applying a magnetic field 566 for a short period of time that substantially prevents the running magnetic tape 554 from running through the magnetic field 566. Magnetic tape 544 may be similar to magnetic tape 10. Magnetic tape 544 includes a substrate 556 and a magnetic layer indicated by magnetic orientations 558, 560, and 562. Magnetic tape 544 is driven or run past magnetic head 564 (eg, a 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. If the mark length B is greater than the gap length G, the magnetic orientation 560 of the symmetric servo mark 561 may no longer be symmetric because the trailing edge of the magnetic field is longer in the servo mark. The magnetic orientation 560 is the orientation of the symmetric servo mark 561. Symmetric servo mark 561 includes a varying magnetic orientation 560 that varies along mark length B. The magnetic orientation 560 is substantially equal to the direction of the magnetic field 566 and may be line symmetric.

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

In general, the angle between the first magnetic field pattern region (at the 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. Is also good. In one example, the magnetic direction 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 symmetric servo marks 561 that are similarly oriented. Within the magnetic orientation 560, one end of the symmetric servo mark 561 is substantially perpendicular to the substrate 556 and includes a magnetic orientation directed toward the substrate 556, and the other end of the symmetric servo mark 561 is The intermediate portion of the symmetric servo mark 561 between the two ends, including a magnetic orientation substantially perpendicular to the material 556 and away from the substrate 556, is substantially parallel to the substrate 556. Including various magnetic orientations.

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

In some examples, pulse 572 may be a substantially square wave. In other examples, pulse 572 may have a more complex shape. For example, the controller 30 can increase the current amplitude of the pulse 572 as fast as possible. When the current amplitude reaches a predetermined threshold, the controller 30 can then cut off or stop the current. Alternatively, controller 30 may increase the current amplitude of pulse 572 after a short period has elapsed or expired. Thus, the delivery of short pulses can be controlled by threshold amplitude or time period. In any case, the pulse 572 is relatively instantaneous with respect to the speed of the magnetic tape 554 running near the magnetic head 564.

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

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

The symmetric servo mark 580 is Segment A, B, C, D, And E. These segments are Used to describe the magnetic characteristics of the symmetric servo mark 580. The change in magnetic orientation of the magnetic particles in the symmetric servo mark 580 is In general, It may be continuous from one end of the symmetric servo mark 580 to the other. For example, The magnetic orientation behind the symmetric servo mark 580 (segment E) is Starting at about 170 degrees, It may gradually change to 90 degrees in the middle part of the segment C. next, The magnetic orientation of the middle part of segment C is It may change progressively up to about 10 degrees in front of the symmetric servo mark 580 (segment A). However, The five segments A shown in FIG. 19A, B, C, D and E are Provides a general change to 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 changing magnetic orientation.

Since the angle formed between the substrate 576 and the magnetic orientation is substantially reflected from the front of the servo mark to the back of the servo mark, the symmetric servo mark 580 may be described symmetrically. For example, segment A shows that the front of symmetric servo mark 580 has a magnetic orientation of about 10 degrees (with respect to FIG. 2A). Thus, the magnetic orientation of segment A forms an angle of about 80 degrees above substrate 576. Segment E shows that the back 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 below the substrate 576. In this way, the angles formed by the magnetic orientation of segments A and E are approximately equal. In general, the magnetic orientation of segments A and E can form an angle with substrate 576 of approximately 45 degrees or more. In another example, the magnetic orientation of segments A and E can form an angle with substrate 576 of approximately 75 degrees or more. Although the magnetic orientation of each segment A and E is not directly opposite each other (eg, segments A and E have exactly the opposite magnetic orientation if the magnetic orientation is 180 degrees apart), but the magnetic orientation with respect to substrate 576 Since the angle formed by the orientation is substantially the same between the front of the servo mark and the back of the servo mark, the symmetric servo mark 580 is still described symmetrically.

Like segments A and E, segments B and D are also symmetric. For example, segment B shows that the front middle of the symmetric servo mark 580 has a magnetic orientation of about 60 degrees. Thus, the magnetic orientation of segment B forms an angle of approximately 30 degrees above substrate 576. Segment D shows 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 below the substrate 576. Thus, the magnetic orientation of segments B and D is 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 field lines within symmetric servo marks 580 of magnetic tape 574. These magnetic field lines may correspond to the magnetic field lines 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 field lines 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 marks 580.

In other examples, the particular angle of the magnetic orientation within the symmetric servo mark 580 may vary. That is, the angle of the magnetic orientation in segments A and E may be close to 0 degrees in other examples. Although the exact angle with the substrate 576 generated by the magnetic orientation of the symmetric servo mark 580 may vary, the magnetic orientation before and after the symmetric servo mark 580 may remain substantially symmetric.

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

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

FIG. 20 illustrates an example for generating either a longitudinal bias or a vertical bias on a magnetic tape using two magnetic heads, for example, substantially vertical remanence or longitudinal remanence. Is a flowchart showing a conventional technique. In the example of FIG. 20, the system 26 and the magnetic tape 32 will be described. However, a longitudinal or vertical bias may be generated on any of the magnetic tapes described herein having a larger vertical squareness ratio (eg, magnetic tape 10).

As shown in FIG. 20, the magnetic tape 32 is supplied between two magnetic heads (for example, two heads in the servo head module 28) (600). The system 26 drives the magnetic tape 32 in a first direction toward both magnetic heads (602). The first head generates a magnetic field from one side (side A) of the magnetic tape 32, and the magnetic field is generally oriented along the magnetic tape 32 in a first direction (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.

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

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

After the magnetic bias has been generated on the magnetic tape 32 with the magnetic field in 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 a servo track of the magnetic tape 32. This servo writing 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 unidirectional octant and forming a servo pattern in a directional octant different from the bias. The technique of FIG. 21 is directed to exemplary servo marks formed with the magnetic fields of FIGS. 9A-13B. For illustrative purposes, FIG. 21 describes the magnetic bias and servo marks described in FIG. 9B, which writes servo marks on magnetic tape 280 using magnetic head 290 and magnetic field 307. Although different magnetic heads are described as forming the bias and servo marks, other examples could use the same magnetic head.

As shown in FIG. 21, the user can select a desired directional octant for the magnetic bias (624). The selection of the directional octant for the 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 specific composition of the magnetic tape. You may. In the example of FIG. 21, the selected directional octant for the magnetic bias may be directional octant I, as shown in FIG. 9B.

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

Next, magnetic tape 280 is positioned and driven 630 over magnetic head 290 (eg, a servo head) to form a servo pattern using the plurality of servo marks. In the example of FIG. 9B, the base material of the magnetic tape 280 is disposed at a position away from the magnetic head 290. Next, the magnetic head 290 writes servo marks to form a servo pattern of a directional octant 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 running direction of the magnetic tape 280 to generate the servo mark including the residual magnetization of the directional octant IV substantially opposite to the bias direction of the octant I. To form Each time the magnetic field 307 is generated and applied to the magnetic tape 280, a new servo mark having a magnetic orientation different from the bias is formed.

In general, the remanent magnetization of the bias (eg, non-patterned area) and the servo marks have opposite directional octants. Opposite octants, such as the octants described in FIGS. 9-12, need not be completely opposite to each other. Completely opposite octants, for example, octant pairs I and V or VIII and IV, have three other octants separating them. At least two other octants, for example, octants separated by octant pairs I and IV or V and VIII, may be mentioned as generally opposing each other. That is, for example, both the longitudinal and vertical components of octants I and V are in opposite directions. In octant pairs I and IV, the vertical components are in opposite directions, but the longitudinal components share a common direction.

FIG. 22 is a flow diagram illustrating an exemplary technique for continuously biasing and writing a servo pattern by alternating the direction of the magnetic field. FIG. 22 is schematically illustrated using 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, a servo writing system (eg, system 26 of FIG. 3) drives magnetic tape 522 beyond a single magnetic head 534 (634). When the magnetic tape 522 runs, the magnetic head 534 generates a magnetic field 536B in the first direction, and generates a magnetic bias on the magnetic tape 522 (636). If 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 the servo is generated at the trailing edge of the magnetic field 536A. A mark is written (642). Since the magnetic head 534 switches the direction of the magnetic field 536B, the second direction is opposite to the first direction. Thus, the magnetic orientation of the magnetic bias is substantially opposite to the magnetic orientation of the servo mark. After writing the servo mark (642), the magnetic head 534 switches again from the magnetic field 536A to the magnetic field 536B to generate a magnetic bias (636). In this manner, the magnetic head 534 can continuously alternate or switch the direction of the magnetic field 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 if the write process has not been completed (“NO” branch of block 640), the magnetic head 534 continues to generate a magnetic field 534B (block 640). 636). However, if the magnetic head 534 should not write the servo mark ("NO" branch of block 638) and the write process is completed ("YES" branch of block 640), the magnetic head 534 stops generating the magnetic field ("YES" in block 640). 644).

FIG. 23 is a flow diagram illustrating an exemplary technique for forming symmetric servo marks on a magnetic storage tape. FIG. 23 is schematically illustrated using 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 at writing a symmetric servo mark to 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 writing system (eg, system 26 of 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, direction of the magnetic field) to achieve the desired remanent magnetization to achieve the desired waveform from the servo mark. Can be generated (651). In this way, a magnetic field can be written to the servo mark to achieve a particular remanent magnetization within the octant, as described herein. Based on the bias magnetization of the magnetic tape 554, the resulting servo marks can achieve a particular waveform when read by a read head. Next, the magnetic head 564 delivers a flash pulse of the magnetic field 566 for a short period of time (652). That is, the magnetic field 566 is generated for such a short period that no magnetic field 566 is applied to the magnetic tape 554 when the tape is running. As described herein, a short period can generally be about 10 nanoseconds to 50 nanoseconds or less. The magnetic field 566 creates a magnetic orientation over substantially the entire length of the servo mark on the magnetic tape 554.

If the magnetic head 564 does not write the servo mark (“NO” branch of block 648), but writes more servo marks on the magnetic tape 554, the system continues to drive the magnetic tape 544 to make the servo mark a symmetric servo mark. Keep writing. If the magnetic head 564 does not write the servo mark ("NO" branch of block 648) but writes more servo marks on the magnetic tape 554, the system stops the magnetic tape 544 because the servo writing process is complete. (654).

In another example, a symmetric servo mark for a servo pattern can be written using a plurality of magnetic heads arranged in a row along a tape path. Next, a magnetic field flash pulse can be supplied simultaneously by all 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 simultaneously.

A variety of different biasing and servowriting techniques are described herein in connection with magnetic recording media that define a larger vertical squareness ratio. Each of these techniques can be used alone or in any combination to produce the desired direction of remanence. Each of the magnetic tapes described herein is also a portion of the entire magnetic tape, and each portion is described as an exemplary portion within the magnetic tape.

Claims (80)

A substrate,
A magnetic layer formed on the substrate, the magnetic layer including a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%;
A servo track on the magnetic layer;
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 area in the servo track immediately adjacent to and between the plurality of servo marks, substantially perpendicular to the substrate, and in a second direction opposite to the first direction. A data storage tape comprising: a non-patterned region defining a non-patterned remanent magnetization.   The data storage tape of claim 1, wherein the non-pattern residual magnetization in the second direction is a magnetic bias in the non-pattern area.   3. The data storage tape according to claim 1, wherein each of the plurality of servo marks is alternately arranged with a non-patterned area along a length of the magnetic layer.   4. The transition between each of the plurality of servo marks and the non-pattern region substantially comprises pattern remanent magnetization in the first direction and the non-pattern remanent magnetization in the second direction. A data storage tape according to claim 1.   The remanent magnetization comprises a perpendicular component perpendicular to the substrate and a longitudinal component parallel to the substrate, wherein the longitudinal component is less than 50% larger than the perpendicular component. Item 6. The data storage tape according to any one of Items 1 to 5.   The data storage tape of claim 5, wherein the longitudinal component is less than 25% larger than the vertical component.   7. The data storage tape according to claim 1, further comprising a data track on the magnetic layer. Passing a magnetic tape near a magnetic head, the magnetic tape comprising a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%; a servo track; Steps, including tracks;
Generating a first magnetic field in a first direction along the magnetic tape having the magnetic head; and generating a second magnetic field in a second direction along the magnetic tape by the magnetic head; Alternately performing the following.   9. The method of claim 8, wherein the step of passing the magnetic tape near the magnetic head during the alternation of the first magnetic field and the second magnetic field is continuous.   10. The method according to claim 8, wherein the step of alternately generating the first magnetic field and the step of generating the second magnetic field further includes applying a controlled alternating current to the magnetic head. The described method.   The method of any of claims 8 to 10, wherein the first magnetic field creates a magnetic bias on the servo track having a remanent magnetization in a first direction.   The method of claim 11, wherein the second magnetic field forms a servo mark on the servo track having a remanent magnetization in a second direction opposite to the first direction.   9. The method of claim 8, further comprising using one of a trailing edge of the first magnetic field or a trailing edge of the second magnetic field to create a remanent magnetization in the magnetic layer that is substantially perpendicular to the magnetic tape. The method according to any one of claims 12 to 12.   The first magnetic field and the second magnetic field each define an arched magnetic field pattern having a magnetization substantially perpendicular to the magnetic tape at both a leading edge and a trailing edge of the first and second magnetic fields. 14. The method according to any one of claims 8 to 13, comprising: A tape drive configured to run a magnetic tape, the magnetic tape comprising a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%; a servo track; A tape drive, including data tracks;
Generating a first magnetic field in a first direction along the magnetic tape while the magnetic tape is running near the magnetic head; and generating a second magnetic field in a second direction along the magnetic tape in a second direction. And a magnetic head configured to alternately generate the magnetic field.   16. The tape drive according to claim 15, wherein 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. The described system.   16. The magnetic head further comprising a magnetic field generating circuit that alternately performs a step of generating the first magnetic field and a step of generating a second magnetic field by applying a controlled alternating current to the magnetic head. Or the system of 16. Controlling the magnetic field generation circuit to apply the first magnetic field to the magnetic tape so that the first magnetic field generates a magnetic bias in the servo track having a remanent magnetization in a first direction; And controlling the magnetic field generating circuit so that the second magnetic field forms a plurality of servo marks on the servo track having a residual magnetization in a second direction opposite to the first direction. The system of claim 17, further comprising a processor configured to apply a magnetic field to the magnetic tape.   The magnetic head generates both the first magnetic field and the second magnetic field, and applies one of a trailing edge of the first magnetic field and a trailing edge of the second magnetic field to the magnetic tape. 19. The system according to any one of claims 15 to 18, wherein the system is configured to generate remanent magnetization in the substantially perpendicular magnetic tape.   The magnetic head includes an arc-shaped magnetic field pattern that is substantially perpendicular to the magnetic tape at both leading and trailing edges of the first and second magnetic fields. 20. The system according to any one of claims 15 to 19, configured to generate both. Passing a magnetic tape near the write head;
Generating a short-term magnetic field by the write head to form a symmetrical servo mark on the magnetic tape defining a mark length approximately equal to the gap width of the write head. The step of generating a magnetic field comprises: a first magnetic field pattern region substantially perpendicular to the magnetic tape at a first end of the symmetric servo mark and directed to the magnetic tape;
A second magnetic field pattern region substantially perpendicular to the magnetic tape at a second end of the symmetric servo mark and in a direction away from the magnetic tape;
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.   3. The method of claim 2, wherein each of the first magnetic field pattern area and the second magnetic field pattern area has a direction that forms an angle of 45 degrees or more with the magnetic tape.   24. The method according to claim 22, 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.   6. The magnetic field pattern of claim 1, wherein each of the first magnetic field pattern regions forms a first angle with the magnetic tape, and a second magnetic field pattern region forms a second angle with which the magnetic tape is approximately equal to the first angle. 25. The method according to any one of 21 to 24.   26. The method of any one of claims 21 to 25, wherein generating the magnetic field comprises increasing the current to a threshold and stopping the current within a short period of time.   27. The method of any one of claims 21 to 26, wherein generating the magnetic field comprises increasing a current and stopping the current as soon as the short period has elapsed.   28. The method of any one of claims 21 to 27, wherein the short period is between about 10 nanoseconds and 50 nanoseconds.   Applying the magnetic field to a servo track of the magnetic tape having a magnetic bias to reduce a mark length between about 0.5 micrometers and 3.0 micrometers as at least a portion of a servo pattern in the servo track. 29. The method according to any one of claims 21 to 28, further comprising forming a symmetrical servo mark having. A tape drive for running a magnetic tape,
A write head configured to generate a magnetic field for a short period across the gap width to form a symmetrical servo mark on the magnetic tape defining a mark length approximately equal to the gap width of the write head. Prepare, system. The write head includes:
A first magnetic field pattern region substantially perpendicular to the magnetic tape at a first end of the symmetric servo mark and directed to the magnetic tape;
A second magnetic field pattern region substantially perpendicular to the magnetic tape at a second end of the symmetric servo mark and in a direction away from the magnetic tape;
31. The magnetic tape of claim 30, wherein the magnetic tape comprises a third magnetic field pattern region substantially parallel to the magnetic tape between the first end and the second end. System.   32. The system of claim 31, wherein each of the first magnetic field pattern area and the second magnetic field pattern area has a direction that forms an angle of 45 degrees or more with the magnetic tape.   33. The system of claim 31 or 32, wherein each of the first magnetic field pattern area and the second magnetic field pattern area has a direction that forms an angle of 75 degrees or more with the magnetic tape.   A magnetic field generating circuit configured to apply a current to the write head during the short period, the magnetic field generating circuit increasing the current to a threshold, and then stopping the current in a short period A system according to any one of claims 30 to 33.   35. The system according to any one of claims 30 to 34, further comprising a magnetic field generating circuit configured to increase a current and stop the current as soon as the short period has elapsed.   36. The system of any one of claims 30 to 35, wherein the short period is between about 10 nanoseconds and 50 nanoseconds.   The write head is configured to apply the magnetic field to a servo track of the magnetic tape having a magnetic bias, and the symmetric servo mark has a mark length between about 0.5 micrometers and 3.0 micrometers. 37. The method according to any of claims 30 to 36, wherein the method is at least part of a servo pattern in the servo track having: A substrate,
A magnetic layer formed on the substrate and having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%;
A data storage tape comprising a symmetric servo mark recorded on the magnetic layer,
The symmetric servo mark is
A first remanent magnetization substantially perpendicular to and directed to the substrate at a first end of the symmetric servo mark;
A second remanent magnetization substantially perpendicular to the substrate at a second end of the symmetric servo mark and away from the substrate. A servo pattern including a plurality of symmetric servo marks;
39. The data storage tape of claim 38, further comprising a non-patterned area between the plurality of symmetric servo marks, wherein the non-patterned area comprises substantially zero remanent magnetization.   40. The data storage tape of claim 38 or 39, wherein the symmetric servo marks include a mark length between about 0.5 and 3.0 micrometers. A substrate,
A data storage tape comprising a magnetic layer formed on the base material,
The magnetic layer,
A vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%;
Data storage tape comprising remanent magnetization in a direction substantially perpendicular to the substrate.   42. The data storage tape of claim 41, wherein a direction of the remanent magnetization substantially perpendicular to the substrate forms an angle of at least 45 degrees with the substrate.   43. The data storage tape of claim 42, wherein the direction of the remanent magnetization forms an angle of at least 60 with the substrate.   The remanent magnetization comprises a perpendicular component perpendicular to the substrate and a longitudinal component parallel to the substrate, wherein the longitudinal component is less than 50% larger than the perpendicular component. Item 44. The data storage tape according to any one of Items 41 to 43.   The data storage tape of claim 44, wherein the longitudinal component is less than 25% larger than the vertical component.   46. The data storage tape of any one of claims 41 to 45, wherein the direction of the remanent magnetization is oriented away from the substrate or in the direction of the substrate. A data storage tape comprising at least one servo track of the magnetic layer,
The servo track includes a plurality of servo marks and a non-pattern area,
47. The data storage tape according to any one of claims 41 to 46, wherein a direction of the remanent magnetization of the non-pattern area is substantially opposite to a direction of the remanent magnetization of the plurality of servo marks.   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 a data head with respect to the at least one data track. 48. The data storage tape of claim 47. Passing a magnetic tape through at least one magnetic field, the magnetic tape comprising a substrate and a magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%. , Steps,
Creating at least one remanent magnetization in the magnetic layer in a direction substantially perpendicular to the substrate using at least one magnetic field.   50. The method of claim 49, wherein the direction of the remanent magnetization forms an angle of at least 45 with the substrate.   The step of generating the remanent magnetization includes the step of generating a remanent magnetization having a perpendicular component perpendicular to the substrate and a longitudinal component parallel to the substrate, wherein the longitudinal component includes the perpendicular component. 51. The method of any of claims 49 and 50, wherein the component is less than 50 percent than the component and the vertical component is oriented away from or toward the substrate.   52. The method of claim 51, wherein the longitudinal component is less than 25% larger than the vertical component. Passing the magnetic tape through at least one magnetic field,
Driving the magnetic tape in a first direction;
Passing the magnetic tape through a first magnetic field pattern of a first magnetic head;
Passing the magnetic tape through a second magnetic field pattern of a second magnetic head following the first magnetic field pattern, wherein a longitudinal component of the first magnetic field pattern is: 53. The method of any one of claims 49 to 52, wherein the method is substantially opposite to a longitudinal component of the second magnetic field pattern. Applying the first magnetic field pattern to the magnetic tape from a first side of the magnetic tape;
Applying the second magnetic field pattern to the magnetic tape from a second side of the magnetic tape opposite to the first side. A magnetic tape comprising a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%;
A tape drive configured to run the magnetic tape in a first direction;
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.   The remanent magnetization comprises a perpendicular 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 perpendicular component. 56. The system of claim 55, wherein:   57. The system of claim 56, wherein the longitudinal component is less than 25 percent less in magnitude than the vertical component. The at least one magnetic head is a first magnetic head configured to apply a first magnetic field pattern to the magnetic tape, wherein a longitudinal component of the first magnetic field pattern is substantially a first component. A first magnetic head 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 a longitudinal component of the second magnetic field pattern is substantially the second magnetic field pattern. 58. The system of any one of claims 55-57, comprising: a second magnetic head in a second direction opposite the one direction.   The first magnetic head is disposed on a first surface of the magnetic tape, and the second magnetic head is disposed on a second surface of the magnetic tape opposite to the first surface. Item 58. The system according to Item 57. 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 at least one servo track;
60. The system of any one of claims 55-59, wherein the plurality of servo marks have a remanent magnetization having a second direction different from the first direction of the bias magnetization. A substrate,
A magnetic layer formed on the substrate, the magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%;
A servo track on the magnetic layer, and a servo pattern in the servo track, the first of a longitudinal plane parallel to the base material being in contact with a vertical surface perpendicular to both the base material and the length of the base material. A servo pattern including a plurality of servo marks each including a pattern residual magnetization of a first directional octant arranged on the surface of
A non-patterned area in the servo track, the second directional octant non-pattern disposed on a second surface of the longitudinal surface opposite to the first surface, in contact with the vertical surface; A non-patterned region having remanent magnetization.   62. The data storage tape of claim 61, wherein the second directional octant is located on the same vertical side as the first directional octant.   63. The data storage tape of any of claims 61 and 62, wherein the second directional octant is disposed opposite a vertical plane as the first directional octant.   64. Any of the claims 61-63, wherein the first directional octant and the second directional octant are each bounded by a plane that forms an angle of less than or equal to 60 with the vertical plane. A data storage tape according to claim 1.   65. The method of any of claims 61-64, wherein the first directional octant and the second directional octant are each bounded by a plane that forms an angle of 45 degrees or less with the vertical plane. A data storage tape according to claim 1.   66. Any of the claims 61-65, wherein the first directional octant and the second directional octant are each bounded by a plane that forms an angle of 30 degrees or less with the vertical plane. A data storage tape according to claim 1.   The remanent magnetization of the pattern of each of the plurality of servo marks includes a first pattern remanent magnetization in the first directional octant, the first directional octant and the second directional octant. 67. The data storage tape of any one of claims 61 to 66, comprising a second pattern of remanent magnetization in a third directional octant different from both of the quadrants. A substrate,
A magnetic layer formed on the substrate, the magnetic layer having a vertical squareness ratio of greater than 50% and a longitudinal squareness ratio of less than 50%;
A servo track on the magnetic layer, a servo pattern in the servo track, in contact with a longitudinal surface parallel to the base material, a vertical surface perpendicular to both the base material and the length of the base material; A servo pattern including a plurality of servo marks each having a first directional octant pattern remanent magnetization disposed on the first surface;
A non-pattern area in the servo track, which is disposed on a second surface of the vertical surface opposite to the first surface in contact with the longitudinal surface, and is formed as the first directional octant; A data storage tape comprising non-patterned remanent magnetization in a second directional octant disposed in the opposite direction.   69. The data storage tape of claim 68, wherein the remanent magnetization of the pattern and the non-pattern remanent magnetization each have a direction substantially parallel to the substrate.   70. The data storage tape of claim 69, wherein a direction of the pattern remanence is substantially opposite to a direction of the non-pattern remanence.   71. The method of any of claims 68-70, wherein the first directional octant and the second directional octant are each bounded by a plane that forms an angle of less than or equal to 60 with the longitudinal plane. A data storage tape according to claim 1.   72. The method of any one of claims 68 to 71, wherein the first directional octant and the second directional octant are each bounded by a plane that forms an angle of 45 degrees or less with the longitudinal plane. A data storage tape according to claim 1.   73. The method of any of claims 68 to 72, wherein the first directional octant and the second directional octant are each bounded by a plane that forms an angle of 30 degrees or less with the longitudinal plane. A data storage tape according to claim 1. Forming a plurality of servo marks on servo tracks of a magnetic layer of a magnetic tape, wherein the magnetic layer is formed on a substrate and has a vertical squareness ratio of greater than 50% and a longitudinal squareness of less than 50%. A method comprising the steps of:
The servo track includes a non-pattern region having a bias magnetization,
The plurality of servo marks comprises a residual magnetization different from the bias magnetization and 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 remanent magnetization includes a vertical component opposite to the perpendicular component of the bias magnetization and the remnant magnetization includes the longitudinal component that matches the longitudinal component of the bias magnetization. When,
A waveform having a bipolar pulse when the remanent magnetization has a longitudinal component opposite to the longitudinal component of the bias magnetization;
A waveform having substantially symmetric bipolar pulses when the bias magnetization has substantially randomized vertical and longitudinal components.   The waveform having the bipolar pulse includes a first portion of the remanent 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. Corresponding to a second portion of the remanent magnetization having a stronger pulse corresponding to the following, a vertical component coinciding with the vertical component of the bias magnetization, and the longitudinal component opposite the longitudinal component of the bias magnetization. 75. The method of claim 74, comprising a weaker pulse.   77. The method of claim 74 or 75, wherein the polarity of the waveform is determined by the direction of the vertical and longitudinal components of the bias magnetization.   77. The method of any one of claims 74 to 76, further comprising generating the bias magnetization in the magnetic layer before forming a plurality of servo marks.   78. The method of claim 74, wherein forming a plurality of servo marks comprises: selecting a position of a magnetic head with respect to the magnetic tape; and selecting a direction of a magnetic field pattern generated by the magnetic head. The method according to claim 1.   79. The method of any one of claims 74 to 78, wherein the servo signal is not processed from the read head.   80. The method of any one of claims 74 to 79, further comprising aligning the read head with at least one data track on the magnetic tape in response to generating the servo signal.

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