JP3934890B2 - Initializing method of magnetic recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic recording medium such as a hard disk of a computer, particularly a so-called perpendicular magnetic recording medium that records magnetization in a direction perpendicular to the surface of the magnetic recording medium, and relates to an initialized medium and an initialization method thereof.
[0002]
[Prior art]
As the recording capacity of computers increases, the recording capacity of magnetic recording devices tends to increase. In order to improve the surface recording density, the point is how the recording magnetic domain sequence in the magnetic recording layer formed by the signal magnetic field generated from the magnetic head can be miniaturized.
[0003]
In the so-called longitudinal recording method that has been used in the past, the magnetic recording layer on which recording is performed has a high coercive force and a large square shape in order to cause magnetization to stably exist in the traveling direction of the magnetic head. It is required to have a ratio. This requirement is further increased with the miniaturization of the recording magnetic domain array.
[0004]
However, the increase in the surface recording density of the hard disk is said to be 200% or more per year. With the increase in the linear recording density, the demagnetization of the recording magnetization becomes remarkable and the size of one magnetic particle (magnetic cluster) is minute. The effect of magnetization reversal due to thermal fluctuation cannot be ignored due to the decrease in activation volume accompanying the conversion, and it is said that longitudinal recording is impossible at a super recording density higher than before.
[0005]
Therefore, in place of such a longitudinal recording method, a so-called vertical recording method has been proposed as a method applicable to higher density recording. This method is characterized in that recording is performed by magnetizing in a direction perpendicular to the recording layer surface, as opposed to the longitudinal method in which recording magnetization is written in the recording layer surface.
[0006]
With this perpendicular recording system, not only can the demagnetization of the recording magnetization accompanying the increase in the linear recording density as described above be suppressed, but also the demagnetizing field can be reduced and the recording magnetization can be further stabilized as the density increases. Also, in contrast to the longitudinal method, where it is difficult to magnetize in the in-plane direction unless the recording layer thickness is reduced, the perpendicular recording method has a certain degree of film thickness because of the effect of shape anisotropy. Is advantageous. Further, the perpendicular recording method has an advantage that the influence of magnetization reversal due to thermal fluctuation can be greatly reduced.
[0007]
However, even at a super recording density of 100 Gbit / in ² or more, there is a problem of writing to an adjacent track due to side fringing generated from the side surface of the head. For this reason, it is impossible to realize a recording density higher than that in recording on the current continuous film (simple solid film).
[0008]
Therefore, what is proposed is a so-called discrete track medium in which a non-magnetic row is formed in the circumferential direction of a recording layer and only the magnetic portion is recorded. Due to the presence of the non-magnetic portion, the above-described problem of writing to adjacent tracks can be avoided, and good recording / reproducing characteristics can be obtained.
[0009]
As a conventional example of such a discrete track medium, for example, in JP-A-4-310621 and JP-A-7-129953, a concave portion is provided by directly etching a recording layer, and this concave portion serves as a guard band. A medium is proposed in which a non-magnetic material is embedded and then smoothed to form a magnetic material array aligned in the track direction. However, in these media, the recording layer itself is directly etched, damage to the recording layer (magnetic material) due to the thermal history during etching may occur, and the magnetic characteristics of the magnetic recording layer may be deteriorated.
[0010]
In Japanese Patent Laid-Open Nos. 56-119934 and 2-201730, a recess is formed by etching on the surface of a non-magnetic material (substrate), and after the magnetic material is embedded in the recess, a flattening process is performed. Thus, a medium is proposed in which magnetic material rows arranged in the track direction are formed. However, in these media, it can be said that it is almost impossible to form a magnetic material while maintaining good crystal orientation and perpendicular anisotropy in a fine groove.
[0011]
In any of the above methods, the magnetic characteristics of the magnetic recording layer may be deteriorated by polishing the surface of the magnetic layer (recording layer) in the process of surface smoothing by CMP (chemical mechanical polishing) or the like.
[0012]
In addition, even if smoothing and flattening processing is performed, it is difficult to realize a stable head disk interface (HDI) because irregularities remain on the surface of the medium due to dishing of the recording layer or nonmagnetic layer and the surface is not uniform. It is.
[0013]
In order to solve such problems, the inventors of the present application have already proposed a novel magnetic recording medium structure as Japanese Patent Application No. 2001-2003380. The present invention is a technical proposal related to so-called initialization of the medium of Japanese Patent Application No. 2001-2003380 that has already been proposed. An object of the present invention is to provide a magnetic recording medium and an initialization method that are initialized so that they can be detected optically or magnetically.
[0015]
[Means for Solving the Problems]
In order to solve such a problem, the present invention is a method for initializing a magnetic recording medium, which includes a step of preparing a magnetic recording medium and an initialization step of initializing the prepared magnetic recording medium. The magnetic recording medium in the step of preparing the magnetic recording medium includes a soft magnetic backing layer and a perpendicular magnetic recording layer on a flat nonmagnetic substrate , and the soft magnetic backing layer of the medium is a recording medium. The area between the data track to be reproduced and the area where the servo signal is recorded, or the area where the servo signal is recorded, has a lacking recess for exerting a discrete action, and the recess is filled with a nonmagnetic material to and a magnetic layer is formed, the perpendicular magnetic recording layer is configured with a magnetic anisotropy in the vertical direction of at least a substrate, a planar membrane having no intentionally formed absence recess Is, the initial step is, the greater the magnetic field than the coercive force of the perpendicular magnetic recording layer surface magnetic field a and the perpendicular magnetic recording layer in the direction perpendicular to the applied to the perpendicular magnetic recording layer, uniformly across the perpendicular magnetic recording layer Then, a magnetic field having a magnitude that can reverse only the magnetization of the perpendicular magnetic recording layer at a position opposite to the previously magnetized magnetization direction and where the nonmagnetic layer is not present is perpendicularly magnetized. When applied to the magnetic recording layer, the magnetization of the perpendicular magnetic recording layer corresponding to the servo mark in the area where the data track or servo signal is recorded is reversed.
[0017]
The present invention is also a method for initializing a magnetic recording medium, comprising the steps of preparing a magnetic recording medium and an initializing step of initializing the prepared magnetic recording medium, wherein the magnetic recording medium is prepared The magnetic recording medium in the process includes a soft magnetic backing layer and a perpendicular magnetic recording layer on a flat nonmagnetic substrate , and the soft magnetic backing layer of the medium includes data tracks and data to be recorded and reproduced. The area located between the tracks and the area where the servo signal is recorded have a missing recess for exerting a discrete action, and the recess is filled with a nonmagnetic material to form a nonmagnetic layer, the perpendicular magnetic recording layer, which has a magnetic anisotropy in the vertical direction of at least a substrate, is configured as a planar membrane having no intentionally formed absence recess, wherein the initialization step, vertical A magnetic field perpendicular to the magnetic recording layer surface and larger than the coercive force of the perpendicular magnetic recording layer is applied to the perpendicular magnetic recording layer, and the entire perpendicular magnetic recording layer is uniformly magnetized in one direction in advance. Thereafter, a magnetic field in a direction opposite to the pre-magnetized magnetization direction and a magnitude capable of reversing only the magnetization of the perpendicular magnetic recording layer at a position where the non-magnetic layer does not exist is applied to the perpendicular magnetic recording layer. The configuration is such that the magnetization of the perpendicular magnetic recording layer corresponding to the servo mark in the area where the track and servo signal are recorded is reversed.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described in detail.
[0019]
FIG. 1A is a schematic plan view showing the entire shape of the disk-shaped magnetic recording medium 1 of the present invention, and FIG. 1B is a small portion surrounded by a square in FIG. 100 partial enlarged schematic views are shown. In particular, in FIG. 1B, in order to conceptually show the positions of the servo signal area 90 and the data area 80 (data track group for recording / reproduction), in the present invention, they are deposited on these. The perpendicular magnetic recording layer is drawn in a removed state. 2A and 2B are cross-sectional views conceptually showing a preferred embodiment of the magnetic recording medium of the present invention, respectively. This corresponds substantially to a cross-sectional view taken along the line α. 3A to 3H are schematic cross-sectional views for explaining an example of a suitable manufacturing process of the magnetic recording medium in a stage before the initializing operation of the present invention is performed. FIGS. 4A to 4C are schematic cross-sectional views for explaining the initialization method of the present invention over time.
In FIG. 1A, although not shown, a plurality of data track groups for recording and reproduction are concentrically arranged and formed on a disk substrate. Servo signal regions (locations drawn in a line in the drawing) are formed radially from the center of the disk to the outside.
[0020]
As shown in FIGS. 2A and 2B, the magnetic recording medium 1 of the present invention is a magnetic recording medium including a soft magnetic backing layer 10 and a perpendicular magnetic recording layer 20 on a nonmagnetic substrate 2. In addition, the perpendicular magnetic recording layer 20 is subjected to an initialization operation so that the position of a patterned track or the like can be detected optically or magnetically as described later.
[0021]
The soft magnetic underlayer 10 according to the present invention has a discrete action as if adjacent data tracks are magnetically separated at a position (so-called guard band portion) positioned between the data tracks 22 where data is recorded and reproduced. The recess 10a is provided with a nonmagnetic layer 15 filled with a nonmagnetic material.
[0022]
The missing recess 10a for exerting the discrete action is not only between the data tracks described above, but also in a form in which the signal functions in an area where the servo signal is recorded (servo signal area 90 in FIG. 1). It may be provided. In other words, in the servo signal region 90, a recess corresponding to the servo signal pattern may be formed.
[0023]
As shown in FIGS. 2A and 2B, the perpendicular magnetic recording layer 20 formed on the soft magnetic underlayer 10 and the nonmagnetic layer 15 in the present invention has a magnetic property at least in the vertical direction of the substrate 2. It is configured as a planar film having directivity and having no intentionally formed missing recesses. Here, “the intentionally formed missing recess does not exist” means that, as disclosed in Japanese Patent Laid-open No. Hei 7-129953, which is a conventionally known technique, for example, the magnetic method is consciously performed by a lithography method or the like. The purpose is to exclude those having a layer and forming a recess. Therefore, for example, surface irregularities in nanometer (nm) units, which are generated by the formation of the perpendicular magnetic recording layer 20, are not intentionally formed.
[0024]
The recess 10a in FIG. 2A is formed so as to lack a part in the thickness direction (vertical direction in the drawing) of the soft magnetic backing layer 10 at the place where it is formed. Without being limited to this embodiment, the lacking recess 10a is made to lack substantially all of the thickness direction of the soft magnetic backing layer 10 where it is formed as shown in FIG. 2B. You may form in. Here, “substantially all” refers to a mode in which a portion of the substrate 2 is slightly etched and a nonmagnetic material is filled in a portion of the substrate without departing from the operational effects of the present invention. It is a purpose to include. This is because it can be said that it is extremely difficult to completely remove only the soft magnetic underlayer 10 strictly.
[0025]
In the embodiment of FIG. 2A, the depth (the thickness of the nonmagnetic material 15) D of the lacking recess 10a for causing a substantial discrete action varies depending on the material selection of each member constituting the medium. When the thickness of the soft magnetic backing layer 10 is Ds, it is desirable that D = 0.2 to 0.9 Ds. Further, as shown in FIG. 2A, it is desirable that the soft magnetic backing layer 10 is connected at the lower portion. This is because the magnetic flux easily forms a closed loop between the single magnetic pole head to be used, the perpendicular magnetic recording layer 20 and the soft magnetic underlayer 10, and good recording with high magnetic flux density can be performed.
[0026]
On the other hand, in the case of the embodiment of FIG. 2B, it is difficult to form a domain wall in the soft magnetic backing layer, and there is an advantage that noise due to the magnetic domain of the soft magnetic backing layer can be suppressed.
[0027]
As the non-magnetic substrate 2 in the present invention, those usually used for this type of magnetic recording medium such as aluminum, tempered glass, crystallized glass, carbon plastic, etc. may be used.
[0028]
As the soft magnetic backing layer 10 in the present invention, NiFe, NiFeNb, NiFeMo, FeAlSi, FeTaC or the like is preferably used. The thickness of the soft magnetic backing layer 10 in the data track is about 0.1 to 10 μm. When this thickness is less than 0.1 μm, it becomes difficult for the magnetic flux to form a closed loop between the single magnetic pole head to be used, the perpendicular magnetic recording layer 20 and the soft magnetic underlayer 10, and good reproduction output can be obtained. It becomes impossible. On the other hand, when the thickness exceeds 10 μm, the internal stress of the film increases, and the film tends to be easily cracked.
[0029]
As the perpendicular magnetic recording layer 20 in the present invention, any material such as CoCr, CoCrTa, CoPt, CoCrPt, CoPtCrO, and TbFeCo, which is usually used for the perpendicular magnetic recording layer of this type of magnetic recording medium, may be used. good. The thickness of the perpendicular magnetic recording layer 20 may be appropriately selected in consideration of the head to be used, the recording wavelength to be used, and the like. Usually, it is about 10 to 100 nm. If the thickness is less than 10 nm, the amount of residual magnetization when a signal is recorded on the perpendicular magnetic recording layer 20 becomes very small, so that the reproduction output of the signal tends to be remarkably deteriorated.
[0030]
As the nonmagnetic material (material constituting the nonmagnetic layer 15) filled in the missing recess 10a of the present invention, SiO ₂ , Al ₂ O ₃ , C, or the like is preferably used.
[0031]
On the perpendicular magnetic recording layer 20, it is desirable to form a protective film mainly made of C, ZrO ₂ , SiO ₂ or the like with a thickness of about 1 to 10 nm for the purpose of protecting the magnetic layer. If it is formed too thick, a problem of spacing loss tends to occur, and if it is formed too thin, problems such as durability tend to occur. Further, a lubricating film containing various known organic lubricants may be formed on the protective film.
[0032]
Method for manufacturing magnetic recording medium of the present invention A preferred example of the method for manufacturing a magnetic recording medium of the present invention will be described with reference to FIGS. 3 (A) to (H) and FIGS. 4 (A) to (C). To do.
[0033]
First, as shown in FIG. 3A, the soft magnetic backing layer 10 is formed on the nonmagnetic substrate 2 by sputtering or the like.
[0034]
Next, a resist layer 50 is formed on the soft magnetic backing layer 10 as shown in FIG.
[0035]
Next, as shown in FIG. 3C, a molding die 60 in which concave and convex shapes such as a track gap and a servo signal are finely processed is prepared, and this is pressed while heating the surface of the resist layer 50. Imprint. The imprint shape (resist pattern) shown in FIG. 3D is formed by removing the molding die 60. Note that the resist pattern may be formed by electron beam lithography or the like.
[0036]
Next, the soft magnetic backing layer 10 is etched along the resist pattern by reactive ion etching (RIE) or the like to form a plurality of missing recesses 10a as shown in FIG. At this time, if a part of the soft magnetic backing layer 10 is left in the depth direction at the etched portion of the soft magnetic backing layer 10, the configuration shown in FIG. If all the soft magnetic backing layer 10 is removed, the configuration shown in FIG. 2B is obtained.
[0037]
After removing the remaining resist on the soft magnetic backing layer 10, a nonmagnetic material is sputter deposited as shown in FIG. 3F to form the nonmagnetic layer 15 in the recess 10a of the soft magnetic backing layer 10. Let
[0038]
Next, the soft magnetic backing layer 10 and the nonmagnetic layer 15 are planarized by a method such as chemical mechanical polishing (CMP), so that the surface is planarized and an unnecessary nonmagnetic layer 15 (non-magnetic layer 15) The magnetic material is removed, and the state shown in FIG.
[0039]
Next, as shown in FIG. 3H, the perpendicular magnetic recording layer 20 is deposited by sputtering or the like. Although not shown in the drawings, it is preferable to provide a crystal orientation layer as a base layer in advance in order to obtain a good perpendicular magnetic recording layer 20 before the perpendicular magnetic recording layer 20 is formed. In particular, the formation of the crystal orientation layer only in a portion where there is no lack of the soft magnetic backing layer (a portion where the nonmagnetic layer does not exist) is perpendicular to the data track portion where good magnetic properties are originally required. The magnetic recording layer and the perpendicular magnetic recording layer in the discrete portion where good magnetic properties are not desired are particularly preferable in that the magnetic properties can be differentiated so as to satisfy the original requirements.
[0040]
The magnetic recording medium manufactured based on FIGS. 3A to 3H has the problems of the prior art, that is, the possibility of deterioration of the magnetic properties of the magnetic recording layer and the occurrence of surface non-uniformity. It exhibits extremely excellent effects such as being able to improve. However, the magnetic recording medium manufactured based on FIGS. 3A to 3H is patterned as it is because the surface is uniformly covered with the perpendicular magnetic recording layer 20 as it is. It is difficult to optically or magnetically detect a track or a servo signal. Therefore, the initialization method (magnetization method) of the present invention as shown in FIGS. FIG. 4 illustrates a so-called double-sided recording medium, that is, the soft magnetic backing layer 10 of the present invention and the nonmagnetic layer 15 formed in the absence of the soft magnetic backing layer 10 on both sides of the nonmagnetic substrate 2. And a medium including the perpendicular magnetic recording layer 20 is illustrated.
[0041]
First, as shown in FIG. 4A, a magnetic field perpendicular to the surface of the perpendicular magnetic recording layer 20 (in FIG. 4, a magnetic field indicated by an arrow (α1) from the top to the bottom) and perpendicular to the surface. An external magnetic field H ₁ (H ₁ >> Hc) larger than the coercive force Hc of the magnetic recording layer 20 is applied to the entire surface of the perpendicular magnetic recording layer 20, and the entire perpendicular magnetic recording layer 20 is uniformly distributed in one direction (see FIG. In the case of 4, it is previously magnetized in the downward direction from the top. An arrow schematically described in the perpendicular magnetic recording layer 20 indicates the magnetization direction.
[0042]
Next, as shown in FIG. 4B, a magnetic field in the direction opposite to the previously magnetized magnetization direction (in FIG. 4, a magnetic field indicated by an arrow (β) from the bottom to the top), and An external magnetic field H ₂ having a magnitude sufficient to reverse only the magnetization of the perpendicular magnetic recording layer 20 at a position where the nonmagnetic layer 15 does not exist is applied. The magnitude of the external magnetic field H _{2 in} this case is such that the external magnetic field is generated, for example, a magnetic coupling between the wide recording head (permanent magnet or electromagnet) 40 and the soft magnetic backing layer 15 (represented schematically) Due to the magnetic coupling between (β) and the arrow (γ), the soft magnetic underlayer 15 has such a size that the magnetization of only the perpendicular magnetic recording layer 20 positioned below can be reversed. For example, the external magnetic field H ₂ is set to a magnetic field that is equal to or slightly smaller than the coercive force Hc of the perpendicular magnetic recording layer 20.
[0043]
By continuing the magnetization reversal operation as shown in FIG. 4B in the direction of the arrow 41 along the medium surface, for example, the soft magnetic backing layer 15 and the perpendicular magnetic recording layer as shown in FIG. The magnetization reversal of the perpendicular magnetic recording layer 20 at a predetermined position (position where the nonmagnetic layer 15 does not exist) at which the magnetic recording medium 20 can be magnetically coupled to the magnetic recording layer 20 is completed.
[0044]
In this way, the magnetization direction of the perpendicular magnetic recording layer 20 at a position where the nonmagnetic layer 15 exists below is opposite to the magnetization direction of the perpendicular magnetic recording layer at a position where the nonmagnetic layer 15 does not exist. It will be initialized. By performing such an initialization process, the patterned track position and servo signal (servo mark of the area where the servo signal is recorded) which is covered by the perpendicular magnetic recording layer 20 and is located below the optical track or the magnetic signal are recorded. Can be detected automatically.
[0045]
Although not shown in the drawing, the initial operation of the perpendicular magnetic recording layer 20 (the recording layer located on the lower side of the drawing) on the back side of the substrate is continued by performing the same operation on the back side of the substrate as in FIG. 4B. (Magnetization reversal) is performed.
[0046]
The “perpendicular magnetic recording layer 20 at the position where the nonmagnetic layer 15 is present” refers to a portion of the perpendicular magnetic recording layer 20 formed on the nonmagnetic layer 15. The term “perpendicular magnetic recording layer 20 at a position where no magnetic field exists” is intended to exclude the portion of the perpendicular magnetic recording layer 20 formed on the nonmagnetic layer 15, in other words, on the soft magnetic underlayer 15. This is the portion of the perpendicular magnetic recording layer 20 at a position where the perpendicular magnetic recording layer 20 can be magnetically coupled.
[0047]
【Example】
The present invention will be described in further detail with reference to specific examples.
[0048]
A magnetic recording medium sample of the present invention was manufactured according to the manufacturing process shown in FIGS. As the nonmagnetic substrate 2, crystallized glass for a hard disk having an outer diameter of 65 mm, an inner diameter of 20 mm, and a thickness of 0.63 mm was used. The soft magnetic backing layer 10 was formed by sputtering using NiFe permalloy, the thickness of the flat portion was 500 nm, and the depth of the missing recess 10a was 250 nm. SiO ₂ was used as a nonmagnetic material to fill the missing recess 10a. As the perpendicular magnetic recording layer 20, CoCrPt was formed by sputtering to a thickness of 50 nm.
[0049]
The sample of the present invention thus produced was initialized by the method shown in FIGS. 4 (A) to (C). The external magnetic field H ₁ used for initialization was 800 kA / m (10000 Oe), and the external magnetic field H ₂ was 400 kA / m (5000 Oe).
[0050]
An experiment was carried out to magnetically detect the track position and the servo signal for the sample of the present invention thus produced, and it was confirmed that these magnetic signals could be detected reliably. It was confirmed that optical detection using the Kerr effect was also possible.
[0051]
In addition, since the sample of the present invention adopts a structure in which the perpendicular magnetic recording layer 20 is not subjected to etching after film formation, it is possible to prevent the magnetic characteristics of the perpendicular magnetic recording layer 20 from deteriorating.
[0052]
Further, the sample of the present invention has a structure in which a nonmagnetic material is embedded only in the lacking recess 10a of the soft magnetic backing layer 10 and a perpendicular magnetic recording layer is formed after smoothing and flattening by CMP or the like. Therefore, it is possible to avoid damage to the perpendicular magnetic recording layer that can occur by smoothing and flattening after embedding a nonmagnetic material in the lacking part formed in the perpendicular magnetic recording layer as in the prior art, Also from this viewpoint, it is possible to prevent the magnetic characteristics of the perpendicular magnetic recording layer 20 from deteriorating. Furthermore, the sample of the present invention can eliminate irregularities on the surface of the medium due to dishing of the perpendicular magnetic recording layer and the nonmagnetic layer, which are inevitably generated from the medium structure of the prior art.
[0053]
Of course, the sample of the present invention having the above-described configuration is also experimentally capable of reducing the so-called side crosstalk (reducing cross write / cross read) and improving the tracking accuracy by improving the tracking accuracy. Was confirmed.
[0054]
【The invention's effect】
The effects of the present invention are clear from the above results. That is, the present invention relates to a magnetic recording medium comprising a soft magnetic backing layer and a perpendicular magnetic recording layer on a nonmagnetic substrate, and the soft magnetic backing layer of the medium has data tracks and data to be recorded and reproduced. The area located between the tracks, or the area where the servo signal is recorded has a lacking recess for exerting a discrete action, and the recess is filled with a nonmagnetic material to form a nonmagnetic layer, The perpendicular magnetic recording layer is a planar film having magnetic anisotropy at least in the vertical direction of the substrate and having no intentionally formed recess, and the perpendicular magnetic recording layer at a position where the nonmagnetic layer is present Is initialized so that the magnetization direction of the perpendicular magnetic recording layer at a position where the nonmagnetic layer does not exist is opposite to that of the perpendicular magnetic recording layer. It is possible to detect the position and the servo signal of the patterned track located beneath optically or magnetically.
[Brief description of the drawings]
FIG. 1 (A) is a schematic plan view showing the overall shape of a disk-shaped magnetic recording medium of the present invention, and FIG. 1 (B) is a micro-part surrounded by a square in FIG. 1 (A). FIG.
FIGS. 2A and 2B are sectional views conceptually showing preferred embodiments of the magnetic recording medium of the present invention, respectively.
FIGS. 3A to 3H are schematic cross-sectional views for explaining an example of a suitable manufacturing process of the magnetic recording medium of the present invention over time. FIGS.
4 (A) to 4 (C) are schematic cross-sectional views for explaining the initialization method of the present invention over time.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Magnetic recording medium 2 ... Nonmagnetic board | substrate 10 ... Soft magnetic backing layer 10a ... Defect recess 15 ... Nonmagnetic layer 20 ... Perpendicular magnetic recording layer

Claims (2)

Preparing a magnetic recording medium;
An initialization step of initializing the prepared magnetic recording medium, and an initialization method of the magnetic recording medium,
Magnetic recording medium in the step of preparing the magnetic recording medium, on a plate-shaped non-magnetic substrate, comprising a soft magnetic underlayer, a perpendicular magnetic recording layer,
The soft magnetic underlayer of the medium has a lacking recess for exerting a discrete action in an area located between data tracks where recording / reproduction is performed, or an area where a servo signal is recorded. Is filled with nonmagnetic material to form a nonmagnetic layer,
The perpendicular magnetic recording layer has a magnetic anisotropy in at least the vertical direction of the substrate, and is configured as a planar film having no intentionally formed lacking recess ,
In the initialization step, a magnetic field perpendicular to the surface of the perpendicular magnetic recording layer and a magnetic field larger than the coercive force of the perpendicular magnetic recording layer is applied to the perpendicular magnetic recording layer so that the entire perpendicular magnetic recording layer is uniformly uniform. Pre-magnetized in the direction,
Thereafter, a magnetic field having a magnitude that can reverse only the magnetization of the perpendicular magnetic recording layer in a position opposite to the pre-magnetized magnetization direction and where the nonmagnetic layer is not present is applied to the perpendicular magnetic recording layer, A method of initializing a magnetic recording medium, comprising reversing the magnetization of a perpendicular magnetic recording layer corresponding to a servo mark in an area where a data track or a servo signal is recorded. Preparing a magnetic recording medium;
An initialization step of initializing the prepared magnetic recording medium, and an initialization method of the magnetic recording medium,
Magnetic recording medium in the step of preparing the magnetic recording medium, on a plate-shaped non-magnetic substrate, comprising a soft magnetic underlayer, a perpendicular magnetic recording layer,
The soft magnetic underlayer of the medium has a lacking recess for exerting a discrete action in an area located between data tracks on which recording / reproduction is performed and an area where a servo signal is recorded. Is filled with nonmagnetic material to form a nonmagnetic layer,
The perpendicular magnetic recording layer has a magnetic anisotropy in at least the vertical direction of the substrate, and is configured as a planar film having no intentionally formed lacking recess ,
In the initialization step, a magnetic field perpendicular to the surface of the perpendicular magnetic recording layer and a magnetic field larger than the coercive force of the perpendicular magnetic recording layer is applied to the perpendicular magnetic recording layer so that the entire perpendicular magnetic recording layer is uniformly uniform. Pre-magnetized in the direction,
Thereafter, a magnetic field having a magnitude that can reverse only the magnetization of the perpendicular magnetic recording layer in a position opposite to the pre-magnetized magnetization direction and where the nonmagnetic layer is not present is applied to the perpendicular magnetic recording layer, A method of initializing a magnetic recording medium, comprising reversing the magnetization of a perpendicular magnetic recording layer corresponding to a servo mark in an area where data tracks and servo signals are recorded.

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