JPH1116138A - Magnetic recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a sharp recording magnetic domain less in the disturbance of a magnetic domain structure by performing the yaw angle correction of a prescribed angle in every area of each recording track when a magnetic head is moved from the inner circumferential side toward the outer circumferential side. SOLUTION: A magnetic head 14 is supported by a suspension 19 and is provided with revolving motion from the inner circumference toward the outer circumference of a magnetic disc by an actuator 20. In a recording track area To 12 on the inner circumferential side of a range from a radius Ro to a radius Ro+a, the yaw angle of a recording head magnetic pole 16 to the tangential line of a recording track 21 in a circumferential shape is small and recording bits 22 are formed to be approximately orthogonal to the recording track 21. When a magnetic area is moved into a recording track area Tm 13 on the outer circumferential side from a radius Rm to a radius Rm+a, the suspension 19 is revolved at an angle θm. At this time, the magnetic head 14 is corrected at an angle ϕm to the shaft of the suspension 19 by an angle correcting function and as the result, the recording bits 22 are formed to be approximately orthogonal to the recording track 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus having a high linear recording density and a high track density, and particularly suitable for improving the areal recording density.

[0002]

2. Description of the Related Art Currently, practically used magnetic recording systems include an N-pole and an N-pole, which are parallel to the surface of a magnetic recording medium and are magnetic poles.
This is an in-plane magnetic recording system in which magnetic recording is performed by magnetizing the poles, the S pole, and the S pole in a direction in which they face each other. In longitudinal magnetic recording, to improve the linear recording density, the product of the residual magnetization (Br) and the magnetic film thickness (t) of the magnetic film as the recording medium is reduced to reduce the effect of the demagnetizing field during recording. It is necessary to increase the coercive force. Further, in order to reduce the medium noise generated from the magnetization transition, the easy axis of the magnetic film needs to be oriented parallel to the substrate surface.

As a magnetic film, Co is used as a main component, and Cr, Ta, Pt, Rh, Pd, Ti, Ni, Nb,
A Co alloy thin film to which Hf or the like is added is used. As the Co alloy constituting the magnetic thin film, a material having a hexagonal close-packed lattice structure (hereinafter, referred to as an hcp structure) is mainly used. The crystal has an axis of easy magnetization in the c-axis, the <0.1> direction, and the axis of easy magnetization is oriented in the in-plane direction. The magnetic thin film is formed by a vacuum evaporation method or a sputtering method.

[0004] In order to improve the linear recording density and reproducing output when magnetic recording is performed and reduce the reproducing noise to improve the magnetic recording characteristics, the above-mentioned in-plane orientation of the c-axis of the Co alloy thin film is improved. It is necessary to control the crystal grain size. In order to control the crystal orientation and grain size of the magnetic thin film, an underlayer for structure control is formed between the substrate and the magnetic film. As the underlayer, C
r as the main component, and Ti, Mo, V, W, Pt, P
A material to which d or the like is added is used.

On the other hand, the perpendicular magnetic recording system is a system in which recording domains perpendicular to the recording medium surface and adjacent recording bits form magnetic domains in antiparallel to each other, and has the advantage of reducing the demagnetizing field at the boundary between recording bits. And is one of the powerful means of high-density magnetic recording.

[0006] For high-density recording by in-plane recording, the thickness of the magnetic film must be 20 nm or less as described above. In this case, the diameter of the magnetic particles constituting the magnetic film also becomes small, so There is a problem that the recording magnetization disappears due to a periodic fluctuation. On the other hand, perpendicular recording has the advantage that the magnetic film thickness can be made thicker than in-plane recording, and the recording magnetization can be stably maintained. In perpendicular recording, it is necessary to orient the easy axis of magnetization of the magnetic film perpendicular to the substrate surface in order to reduce medium noise generated from magnetization transition and improve linear recording density.

The magnetic film contains Co as a main component and contains Cr, Ta, Pt, Rh, Pd, Ti, Ni, Nb,
A Co alloy thin film to which Hf or the like is added is used. As the Co alloy constituting the magnetic thin film, a material having a hexagonal close-packed lattice structure (hereinafter, referred to as an hcp structure) is mainly used. The crystal has an easy axis of magnetization in the c-axis, the <0.1> direction, and the easy axis of magnetization is oriented in the vertical direction. The magnetic thin film is formed by a vacuum evaporation method or a sputtering method. In order to improve the linear recording density and reproducing output when magnetic recording is performed, and to reduce the reproducing noise and improve the magnetic recording characteristics, the perpendicular orientation of the c-axis of the Co alloy thin film is improved and the crystal grain size is reduced. Control is needed. In order to control the crystal orientation and grain size of the magnetic thin film, an underlayer for structure control is formed between the substrate and the magnetic film. As the base layer, a material having an amorphous structure or a material having an hcp structure is used.

In order to improve the areal recording density of a magnetic recording apparatus, it is necessary to increase the track density in addition to the linear recording density. To improve the track density, magnetic recording (high track density recording, high TP) in which the track width of the recording / reproducing head is narrowed and the recording track interval is set small.
I recording), and furthermore, the disturbance of the magnetic domains at both ends of the recording track due to the leakage magnetic field from the end of the magnetic pole of the recording head needs to be reduced in all regions from the inner circumference to the outer circumference of the magnetic disk.

In the conventional magnetic disk drive, the magnetic head is fixed at a fixed angle on a suspension supporting the magnetic head, and the recording area moves from the inner peripheral side to the outer peripheral side of the magnetic recording medium. At this time, an angular deviation (yaw angle) of the magnetic pole of the magnetic head occurs with respect to the relative movement direction (tangential direction of the recording track) between the magnetic head and the magnetic recording medium. Becomes larger. This is due to an increase in medium noise in the reproduced signal,
A decrease in the effective recording track width, a decrease in the positioning accuracy of the recording / reproducing head, and the like have occurred, and have become serious obstacles to the improvement in the areal recording density.

As one method for solving this problem, a method for controlling the in-plane orientation of the magnetic anisotropy of a magnetic film constituting a magnetic recording medium in a circumferential direction or a radial direction, and a method for controlling the magnetic isolation of magnetic particles. Controlling and other methods have been proposed,
In particular, the recording track width was insufficient to achieve a high areal recording density of 1 μm or less.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, reduce the disturbance of recording magnetic domains at both ends of a recording track, and make a magnetic recording apparatus particularly suitable for high-track-density magnetic recording. Is to provide.

[0012]

SUMMARY OF THE INVENTION The present invention relates to an in-plane or perpendicular magnetic recording medium formed on a disk-shaped magnetic disk substrate, a magnetic head for recording / reproducing, a suspension for supporting the magnetic head, a magnetic recording medium. In a magnetic recording apparatus having a drive system and an actuator for relatively moving a magnetic head, (1) when the magnetic head moves from the inner peripheral side to the outer peripheral side of the magnetic disk during recording and reproduction, the angle of the magnetic head magnetic pole with respect to the tangent to the recording track A function for correcting a deviation (yaw angle) is provided. (2) A fixed yaw angle correction is performed for each of a plurality of recording tracks obtained by dividing a recording track on a magnetic disk from a radius Rm to an area of Rm + x. Servo marks in which specific identification symbols are provided in respective areas consisting of track radii Rm to Rm + x are formed on a recording medium in advance, and (4) By to have the ability to move relative to the angle of the suspension of the magnetic head supporting this, to achieve the above object.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same reference numerals indicate portions having the same functional characteristics.

Referring to FIG. 1, one embodiment of the magnetic recording apparatus of the present invention will be described. The magnetic recording device includes a magnetic disk 1, a magnetic head for recording and reproduction, a suspension for supporting the magnetic head 3, an actuator 4, a voice coil motor 5, a recording and reproduction circuit 6, a positioning circuit 7, an interface control circuit 8, and the like. You.

The magnetic disk 1 is formed on a disk-shaped substrate such as a glass substrate, a Si substrate, a NiP-coated aluminum substrate, or a carbon substrate, and an underlayer for controlling the crystal orientation of a magnetic film, and a magnetic layer formed thereon. The magnetic recording medium includes a film, a protective film, and the like, and a lubricating film is coated on the protective film. The magnetic film is mainly composed of Co and contains Cr, P
Using the material of the hcp structure to which t, Ti, Ru, Ta, W, Mo, Pd, etc. are added, the c axis of the easy axis of the magnetic film is oriented in the plane or in the vertical direction. In order to obtain an in-plane recording medium in which the c-axis of the magnetic film is oriented parallel to the substrate surface, Cr is used as a main component as an underlayer for structure control, and Ti,
A material to which V, Ru, Ta, W, Mo, or the like is added is used. On the other hand, in order to obtain a perpendicular recording medium in which the c-axis of the magnetic film is oriented perpendicular to the substrate surface, a nonmagnetic CoCr alloy, Ti, TiCr alloy or Pt, Ru, Ta, Mo is used as an underlayer for structure control. Hcp containing Pd, Pd, etc.
A polycrystalline or amorphous underlayer having a structure or an amorphous underlayer such as Si or Ge is used.

The magnetic head comprises a slider, a magnetic pole of a magnetic recording head provided thereon, and a magnetoresistive, giant magnetoresistive, or spin-valve element for reproducing a recorded signal. In order to reduce disturbance of the recording magnetic domain at the end of the track during magnetic recording, it is desirable that both ends of the track of the trailing and leading magnetic poles of the recording head are aligned. It is preferable that the track width of the reproducing head is smaller than the track width of the recording head magnetic pole in order to reduce reproduction noise generated from both ends of the recording track.

The magnetic head 2 is supported by the suspension 3 and has a function of correcting a yaw angle generated when the magnetic head moves from the inner peripheral side to the outer peripheral side of the magnetic disk.

The contents of the present invention will be described in more detail with reference to FIGS. 2 (a), 2 (b) and 2 (c). A number of recording tracks are formed on the magnetic recording medium 11 in a range from the radius Ro to Rn (0 <n). The recording tracks formed in the range of the radius Ro to Rn (0 <n) are the inner recording track areas To12, To12, which are displayed in the range of the radius Ro to the radius Ro + a.
The recording tracks are grouped into a plurality of recording track areas, such as a recording track area Tm13 on the outer peripheral side displayed in a range from the radius Rm to the radius Rm + a (0m <n). In the area divided into the recording track area To12 and the recording area Tm13, a symbol for identifying each area is provided.
It is provided on the medium in advance by a servo track writer or the like.

In the recording track area To12 and the recording track area Tm13, the yaw angle correction that occurs when the magnetic head 14 moves from the inner circumference to the outer circumference is corrected by a certain amount of angles φo and φm for each group. Make corrections. The yaw angle correction is performed by detecting the rotation angle when the suspension 19 rotates by an angle θm, transmitting the rotation angle to a rotation bearing that fixes the suspension 19 and the magnetic head, and rotating the magnetic head by an angle θm. When dividing the recording track area, a recording track having a radius Rm and a radius Rm
There are 10 to 20 recording tracks between the + a recording tracks, the yaw angle correction amount in this area is fixed, and the area is set so that the yaw angle deviation in this area is 2 degrees or less. It is desirable to do.

The magnetic head 14 has a magnetic pole 16 for recording and a magnetoresistive head 1 for reproduction on a slider 15.
7 and a magnetic shield film 18. The magnetic head 14 is supported by a suspension 19, and is given a rotational motion by an actuator 20 from the inner circumference to the outer circumference of the magnetic disk.

As shown in FIG. 2, in the magnetic recording apparatus of the present invention, the recording head magnetic pole 16 with respect to the tangent of the circular recording track 21 in the inner recording track area To12 in the range from the radius Ro to the radius Ro + a. The recording bit 22 is formed substantially perpendicular to the recording track 21 as shown in FIG. 2B. When the recording area moves from the radius Rm to the area Tm13 on the outer peripheral side of the radius Rm + a, the suspension 1 supporting the magnetic head
9 rotates by an angle θm. At this time, the magnetic head is corrected by an angle φm with respect to the axis of the suspension by the angle correction function provided in the magnetic head.
As shown in (c), the recording bit area 22 on the outer peripheral side recording track area 13 is also the same as the recording track area 12 on the inner peripheral side.
Are formed substantially perpendicular to the recording track 21.

On the other hand, in a conventional magnetic recording apparatus,
As shown in FIG. 3, the angle deviation (yaw angle) of the magnetic pole of the magnetic head with respect to the recording track is small in the inner recording track 31, and as a result, the recording bit 22 is substantially orthogonal to the recording track 21 as shown in FIG. Can be formed. However, when the magnetic head 14 moves to the outer peripheral side of the magnetic recording medium 11 and forms the recording track 32 on the outer peripheral side, the magnetic head magnetic pole 16 is greatly inclined with respect to the recording track 21, and as a result, FIG. As described above, the recording bit 22 is formed to be inclined with respect to the recording track, and the recording magnetic domain structure at both ends of the recording track is greatly disturbed, thereby causing reproduction signal noise.

As an example, a ring type magnetic head having a recording head magnetic pole having a track width of 2 μm and a gap length of 0.2 μm,
Using a magnetoresistive (MR) element for reproduction and using a magnetic head having a track width of 1.5 μm and a shield interval of 0.2 μm for the MR element, magnetic recording is performed by the magnetic recording apparatus of the present invention shown in FIG. went. The distance (spacing) between the medium surface and the magnetic head surface during magnetic recording was set to 50 nm. After the magnetic recording, the recorded magnetization states formed in the inner and outer recording track areas are measured with a magnetic force microscope (MF).
M), and the off-track profile of the recording signal was precisely measured. In this embodiment, the linear recording density is 100 k
FCI (Flux per Change) will be described, but a similar tendency can be obtained with other linear recording densities.

For comparison, using the same magnetic head,
The recording magnetization state formed in the inner and outer recording track regions by the conventional magnetic recording apparatus of FIG. 3 was observed with a magnetic force microscope (MFM), and the off-track profile of the recording signal was measured.

FIG. 4A shows the off-track profile of the recording signals on the inner and outer peripheral sides of the sample magnetically recorded by the magnetic recording apparatus of the present invention (FIG. 2). As is clear from the figure, the intensity of the recording signal is sharply attenuated at both ends of the recording track, and a sharp recording magnetic domain is formed at the end of the track.

According to this embodiment, the width of the disturbance of the recording magnetic domain at the end of the recording track is about 0.2 μm or less, which is almost equal to the gap length of the magnetic pole of the recording head, and uses a recording head having a narrow gap length. Can be further reduced. According to the magnetic recording device of the present invention, the inner track and the outer track of the magnetic disk show substantially the same off-track profile.
It is clear that magnetic recording with a high track density and small disturbance of the recording magnetic domain structure at both ends of the track is possible.

On the other hand, FIG. 4B shows an off-track profile of recording signals on the inner peripheral side and the outer peripheral side of a sample magnetically recorded by the conventional magnetic recording apparatus (FIG. 3). In this case, on the inner peripheral side, the intensity of the recording signal attenuates relatively steeply at both ends of the recording track, and a sharp recording magnetic domain is formed at the end of the track. However, on the outer circumference side, the off-track profile becomes asymmetrical, the track profiles at both ends of the recording track become broad, and the track width of the recording signal is reduced by 25% or more compared to the magnetic pole width of the magnetic head. Recognize. In particular, the width of the disturbance of the recording magnetic domain at the end of the track on the outer peripheral side is more than twice as large as the gap length of the recording head, which is a serious obstacle to increasing the track density.

FIG. 5 shows a comparison of the trajectories until the magnetic head moves from a specific recording track to another recording track until it is positioned on a predetermined recording track. In the figure, it is better that the displacement of the magnetic head trajectory is small and the time for convergence to a predetermined track position is short. It is preferable that the deviation (positioning accuracy) from the center of a predetermined recording track when the movement of the magnetic head converges is small.

FIG. 5A shows a locus until the magnetic head converges to a predetermined recording track position when the magnetic head moves from one recording track to another recording track in the magnetic recording apparatus of the present invention shown in FIG. It is a comparison. In the figure, the vertical axis indicates the displacement (relative value) of the movement locus of the magnetic head.
The horizontal axis indicates the convergence time (relative value) of the predetermined track to the target position, the solid line indicates the characteristic on the inner peripheral side of the magnetic disk, and the broken line indicates the characteristic on the outer peripheral side. In the magnetic recording apparatus of the present invention, the recording track areas are grouped in a range from the radius Rm to the radius Rm + a, and an identification symbol is recorded in advance on the magnetic recording medium for each group. Since the yaw angle correction amount of the magnetic head is determined for each area, as is apparent from the figure, the recording track position is determined in a very short time from when the magnetic head starts moving until it converges to a predetermined recording track position. Is achieved, the positional deviation (positioning accuracy) from the center of the target recording track is as small as 0.1 μm, and a high-accuracy and high-speed tracking operation is possible.

FIG. 5B shows a comparison of the trajectory of the conventional magnetic recording apparatus shown in FIG. 3 until the magnetic head moves to a different recording track and converges to a predetermined recording track position. . In this case as well, it is achieved in a very short time from the start of the movement of the magnetic head to the convergence to the predetermined recording track position, but the positional deviation from the target recording track center (positioning accuracy) is about 0 on the inner peripheral side. .
Although relatively high-precision positioning of 15 μm is possible,
On the outer periphery side, the magnetic domain structure at the end of the recording track is largely disturbed, so that the positioning accuracy is degraded to 0.2 μm or more.

FIG. 5C shows a comparative example in which the recording tracks are not divided into groups as in the present invention, and the yaw angle correction is performed for each recording track. In this case, since the yaw angle correction and the tracking operation are performed in parallel, it is apparent that it takes an extremely long time to converge on a predetermined track.

[0032]

As described above in detail, according to the present invention, the recording tracks of the magnetic disk are grouped from the inner radius to the outer radius in the range from the disk radius Rm to the radius Rm + a. A symbol for identifying each recording track area is formed on the recording medium in advance, and when the magnetic head moves from the inner circumference to the outer circumference, a predetermined angle is set for each of the recording track areas. Is provided, a sharp recording magnetic domain with less disturbance of the magnetic domain structure at the end of the recording track can be formed in all regions from the inner periphery to the outer periphery of the recording medium. As a result, high-precision positioning characteristics,
It is possible to provide a magnetic recording apparatus suitable for magnetic recording with high areal recording density and high S / N characteristics of a reproduction signal.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a magnetic recording and reproducing device.

FIG. 2 is a schematic plan view of a magnetic recording apparatus according to an embodiment of the present invention, and a partially enlarged schematic view of a recording state on an inner peripheral side and an outer peripheral side of a disk.

FIG. 3 is a schematic plan view of a conventional magnetic recording apparatus and an enlarged schematic view of a recording state on the inner and outer peripheral sides of a disk.

FIG. 4 is a characteristic diagram showing an off-track profile of a recording signal according to the present invention and a conventional apparatus.

FIG. 5 is a diagram showing a trajectory of a magnetic head during a tracking operation by the present invention and a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic disk, 2 ... Magnetic head, 3 ... Suspension, 4 ... Actuator, 5 ... Voice coil motor, 6
... Recording / reproducing circuit, 7 ... Positioning circuit, 8 ... Interface control circuit, 11 ... Magnetic recording medium, 12 ... Inner circumference side recording track area To, 13 ... Outer circumference side recording track area Tm, 14 ... Magnetic head, 15 ... Slider, 16 ... Recording head magnetic pole, 17 ... Magnetoresistance effect reproducing head, 1
8 magnetic shield film, 19 suspension, 20 actuator, 21 recording track, 22 recording bit, 31 inner recording track, 32 outer recording track.

Continued on the front page (72) Inventor Masaaki Nihon 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (3)

[Claims] A magnetic recording medium for forming recording magnetization in a direction parallel or perpendicular to a surface of a magnetic disk substrate; a magnetic head for recording and reproducing magnetic information on and from the magnetic recording medium; a suspension for supporting the magnetic head; In a magnetic recording apparatus including a medium and a drive system for relatively moving the magnetic head, and an actuator for positioning the magnetic head at a predetermined track position on the magnetic recording medium, the magnetic head moves from the inner periphery of the magnetic disk during recording and reproduction. A magnetic recording device having a function of correcting a yaw angle of a magnetic head generated when the magnetic head moves to an outer periphery. 2. The magnetic recording apparatus according to claim 1, wherein the radius Rn of the disk-shaped magnetic recording medium (n = 0, 1, 2,...).
For the recording track of n), the recording track is divided into a plurality of recording track areas each having an area of a radius Rm to Rm + x (0 <m <n, x: integer), and the recording track area is magnetically divided. A magnetic recording apparatus wherein a yaw angle correction amount of a head is uniquely set. 3. The magnetic recording apparatus according to claim 2, wherein an identification symbol for specifying each recording track area having a recording track radius Rm to Rm + x (0 <m <n, x: integer) is specified. A magnetic recording device formed in advance on a recording medium surface.