JP2015185202A - Magnetic recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording device which achieves a further higher recording density by using a shingled-write recording method.SOLUTION: A magnetic recording device of an embodiment includes a magnetic disk, and a magnetic head assembly including a main magnetic pole which has a medium facing surface facing the magnetic disk and in which the width of a leading edge of the medium facing surface of the main magnetic pole is substantially the same as the width of a trailing edge of the medium facing surface of the main magnetic pole, a magnetic head which is mounted with the main magnetic pole, a head slider on which the magnetic head is mounted, a suspension having one end joined to the head slider, and an actuator arm which is attached to the other end of the suspension. Overwriting is performed in a single direction from the inner circumference to the outer circumference of the magnetic disk, and the skew angle is 2.5 degrees of less.

Description

  Embodiments described herein relate generally to a magnetic recording apparatus.

  In the 1990s, the practical use of MR (Magneto-Resistive effect) and GMR (Giant Magneto-Resistive effect) heads triggered a dramatic increase in HDD (Hard Disk Drive) recording density and recording capacity. showed that. However, since the problem of thermal fluctuation of magnetic recording media has become apparent since the 2000s, the speed of increase in recording density has temporarily slowed down. Even so, perpendicular magnetic recording, which is in principle advantageous for high-density recording over in-plane magnetic recording, was put into practical use in 2005. Until 2010, the recording density of HDDs was about 40% per year. It showed growth.

  However, even when a high recording density is realized and the perpendicular magnetic recording method is used, the recording density increasing speed is once again stagnant. One factor is a rapid increase in the track density of the magnetic recording medium. The recording density is the product of the “linear recording density” in the circumferential direction of the recording medium and the “track density” in the radial direction. The increase in track density is largely due to physical factors such as the reduction of the width of the main pole of the recording head and the improvement of alignment accuracy by the servo system. The track density increases rapidly while compensating for the increased linear recording density. It has risen.

  The width of the main pole of the recording head usually needs to be narrower than the width of the track. However, since the track density has increased, the track width of the magnetic recording medium has decreased, and the width of the main pole has suddenly narrowed, the magnetic field that can be generated by the recording head has also decreased, making it impossible to write to the recording medium. .

  As a recording method that can solve this problem, a “shingled magnetic recording (SMR) method” has been proposed. A recording area having a large width is formed by once recording on a track using a recording head having a main pole width wider than the track width. Next, when recording an adjacent track, the previously recorded track is overwritten to reduce the width of the previously recorded track. This makes it possible to perform recording with a recording head having a main pole width wider than the track width, and solves the problem of reducing the recording magnetic field, which becomes a problem as the track density increases.

  However, in the roof tile recording system, a main magnetic pole having a width wider than usual is used, so that a large recording magnetic field is generated as compared with normal recording (CMR: conventional magnetic recording). The generation of a large magnetic field is due to the fact that the area of the surface of the main pole facing the magnetic recording medium can be widened. However, it is known that the generated magnetic field is usually curved at the edge of the main pole, and the quality of the magnetic field is poor.

  Thus, in the roof tile recording method, recording is performed using a part of one side of the wide main magnetic pole. For this reason, the ratio of the portion recorded by the curved magnetic field from the edge of the main pole is relatively increased with respect to the entire track remaining after overwriting. Therefore, even if the roof tile recording method is used, the recording density cannot be increased greatly, and the improvement effect becomes small.

JP 2005-108410 A US Pat. No. 6,185,063

  The present embodiment provides a magnetic recording apparatus that achieves a higher recording density by using a roof tile recording method and has a reduced reading error rate.

  The magnetic recording apparatus according to the present embodiment is a main pole having a magnetic disk and a medium facing surface facing the magnetic disk, and the leading edge of the main pole on the medium facing surface has a width of the main pole. A main pole substantially the same as the width of the trailing edge on the opposing surface; a magnetic head on which the main pole is mounted; a head slider on which the magnetic head is mounted; and a suspension on which the head slider is joined to one end; A magnetic head assembly having an actuator arm mounted on the other end of the suspension, and writing is performed in one direction from the inner periphery to the outer periphery of the magnetic disk, and the skew angle is 2.5 degrees. It is as follows.

FIG. 1A is a plan view of the main magnetic pole according to the first embodiment viewed from a magnetic recording medium. FIG. 1B is a cross-sectional view of the main pole cut along a cutting line AA shown in FIG. 1A. 1C is a cross-sectional view of the main pole cut along a cutting line BB shown in FIG. 1B. 2A to 2C are diagrams for explaining a symmetrical roof tile recording method in a magnetic recording apparatus of a comparative example. FIG. 3 is a diagram showing the relationship between the skew angle and the read error rate when magnetic heads each having a rectangular main pole and an inverted trapezoidal main pole are used in a symmetrical roof tile recording system. FIG. 4 is a view showing the dependency of the read error rate on the position of the magnetic disk in the radial direction when magnetic heads each having a rectangular main pole and an inverted trapezoidal main pole are used in the symmetrical tile recording system. 5A is a top view of the main magnetic pole 10 at the inner periphery of the magnetic disk 180, FIG. 5B is a top view of the main magnetic pole 10 at the outer periphery of the magnetic disk 180, and FIG. A top view of the magnetic head assembly 160 is shown. The figure which shows the radial direction position dependence of the reading error rate with and without the angle α being controlled. FIG. 7A is a diagram showing various conditions and recording density gain, and FIG. 7B is a diagram showing recording density gain under various conditions. FIG. 8 is a diagram showing an outline of the magnetic recording apparatus according to the first embodiment. FIG. 9 is a perspective view showing a head stack assembly on which a head slider is mounted. FIGS. 10A and 10B are diagrams illustrating a main pole according to the second embodiment. The figure which shows the characteristic of the magnetic-recording apparatus by 3rd Embodiment. 12A and 12B are diagrams for explaining the angle α dependency of the SN ratio. FIGS. 13A and 13B are diagrams illustrating an example of a method for setting the angle α. FIGS. 14A and 14B are diagrams showing another example of a method for setting the angle α.

  Hereinafter, embodiments will be described with reference to the drawings.

(First embodiment)
A magnetic recording apparatus according to the first embodiment will be described. The magnetic recording apparatus of this embodiment includes a magnetic head. This magnetic head has a recording unit used in the roof tile recording system.
The recording portion has a main magnetic pole, and this main magnetic pole is shown in FIGS. 1A to 1C. 1A is a plan view of the main magnetic pole as viewed from the recording medium, FIG. 1B is a cross-sectional view taken along the cutting line AA shown in FIG. 1A, and FIG. 1C is a cross-sectional view taken along the cutting line BB shown in FIG. FIG.

  The main magnetic pole 10 according to the present embodiment has a leading shield 20a, a trailing shield 20b, and side shields 20c, 20d on a medium facing surface (hereinafter also referred to as ABS (Air-Bearing Surface)) facing the magnetic recording medium 180. being surrounded. A leading gap g1 is provided between the main pole 10 and the leading shield 20a, and a trailing gap g2 is provided between the main pole 10 and the trailing shield 20b (FIG. 1A). Further, as shown in FIG. 1C, a return yoke 30 is provided so as to surround the main magnetic pole 10. The return yoke 30 is connected to the trailing shield 20b and also to the leading shield 20a (not shown). A coil 40 is provided between the main magnetic pole 10 and the return yoke 30 so as to surround the main magnetic pole 10. By passing a current through the coil 40, a magnetic flux flows through the main magnetic pole 10, and magnetization information is written into the magnetic recording medium 180. The direction of the magnetic flux flowing through the main magnetic pole 10 varies depending on the direction of the current flowing through the coil 40. The leading shield 20a, the trailing shield 20b, and the side shields 20c and 20d prevent the magnetic flux generated from the main magnetic pole 10 from being applied to a region other than the region to be written on the magnetic recording medium.

  In the present embodiment, the main magnetic pole 10 has a rectangular shape as shown in FIG. 1A as a shape on a surface ABS (Air-Bearing Surface) facing the magnetic recording medium 180. In other words, the ABS shape of the main magnetic pole has the leading edge substantially the same as the trailing edge. On the other hand, the shape of the known main pole in the ABS has an inverted trapezoidal shape in which the trailing edge is narrower than the leading edge.

  As described above, in the present embodiment, the shape of the main magnetic pole 10 at the ABS is rectangular, so that the ratio of the track width to the width of the main magnetic pole is kept small, and the main magnetic pole 10 is opposed to the magnetic recording medium 180. The area can be increased.

  As a result, the magnetic field at the remaining track position can be increased while suppressing deterioration in the quality of the magnetic field at the edge of the main pole.

  Using this rectangular main pole, however, causes another problem. This will be described by taking as an example a magnetic head of a comparative example used in the roof tile recording system, in which the shape of the main pole at the ABS has an inverted trapezoidal shape.

  In this comparative example, an angle formed by a boundary line 230 between a track on which writing is performed and a track adjacent in a direction opposite to the writing direction, and a side 220 opposite to the writing direction in the ABS shape of the main pole 210. FIG. 2A to FIG. 2C show the relationship between α and the recording pattern recorded on the magnetic recording medium.

  2A is a top view of the main magnetic pole 210 at the inner periphery of the magnetic recording medium (magnetic disk) 180, and FIG. 2B is the main magnetic pole at the outer periphery of the magnetic recording medium (magnetic disk) 180. FIG. 2C shows a top view of the magnetic head assembly 160. The arrows 240 shown in FIGS. 2A and 2B indicate the direction of overwriting.

  The angle α is a direction from the boundary line 230 between the track on which writing is performed and a track adjacent in the direction opposite to the writing direction toward the side 220 on the opposite side to the writing direction in the ABS shape of the main pole 210. Take right.

  When the angle α is larger than zero, as shown in FIGS. 2A and 2B, the recording pattern written by the trailing edge of the main pole 210 remains as a track. The angle formed by the circumferential direction of the magnetic disk 180 and the center line of the magnetic head is called a skew angle.

  In the current hard disk, the skew angle generally shifts from minus to zero and then increases from the inner periphery to the outer periphery of the magnetic disk 180. At this time, in order to keep the angle α larger than zero, in the inverted trapezoidal main magnetic pole 210 of the comparative example, as shown in FIGS. 2 (a) and 2 (b), the skew angle is smaller than when larger than zero. In some cases, a method of changing the writing direction, that is, a symmetrical shingled magnetic recording method is adopted.

  On the other hand, as in the present embodiment, the skew angle and the read error rate when a magnetic head having a rectangular main pole and an inverted trapezoid main pole are used in the symmetrical roof tile recording method. The relationship is shown in FIG.

  When the rectangular main magnetic pole is used, the recording quality suddenly changes when the skew angle becomes positive. This is because the aforementioned angle α becomes negative with a skew angle of zero, and the pattern recorded on the side of the main pole remains.

  FIG. 4 shows the dependency of the read error rate on the position of the magnetic disk in the radial direction when the magnetic head having the rectangular main pole and the inverted trapezoidal main pole is used for the symmetrical roof tile recording system. The horizontal axis in FIG. 4 indicates the position in the radial direction of the magnetic disk, and is normalized by the radius of the magnetic disk.

  In FIG. 4, a point P1 indicates a point where the target of the angle α is +10 degrees when the rectangular main magnetic pole is used, and a point P2 indicates that the target of the angle α is 0 when the rectangular main magnetic pole is used. Indicates a point that seems to be a degree.

  Point P3 indicates a point where the angle α target when the inverted trapezoid main pole is used is +22 degrees, and point P4 indicates that the angle α target is +12 degrees when the inverted trapezoid main pole is used. A point P5 indicates a point at which the target of the angle α is +22 degrees when the inverted trapezoidal main pole is used. The points P2 and P4 indicate the center of overwriting, that is, the position of half the radius of the magnetic disk.

  As can be seen from FIG. 4, due to variations in the shape of the main pole due to variations in the manufacturing process of the magnetic head and errors in the skew angle, a portion where the angle α becomes negative appears statistically, and reading of the hard disk The error rate is worsened.

  Therefore, in order to use the rectangular main magnetic pole, as shown in FIGS. 5A to 5C, the entire surface of the magnetic recording medium is set so that the angle α is non-negative from the inner periphery to the outer periphery. Thus, a tile recording method in which writing is performed in only one direction, that is, an asymmetric tile recording method may be employed.

  The angle α is a direction from the boundary line 230 between the track on which writing is performed and a track adjacent in the direction opposite to the writing direction toward the side 220 on the opposite side to the writing direction in the ABS shape of the main pole 210. Take right.

  This asymmetric roof tile recording system is used in the magnetic recording apparatus of this embodiment.

  FIG. 5A shows a top view of the main magnetic pole 10 at the inner periphery of the magnetic disk 180, and FIG. 5B shows a top view of the main magnetic pole 10 at the outer periphery of the magnetic disk 180. c) shows a top view of the magnetic head assembly 160. The arrows 240 shown in FIGS. 5A and 5B indicate the direction of overwriting. As can be seen from FIGS. 5A and 5B, the angle α is set to zero at the inner peripheral portion, and the angle α is set to a positive value at the outer peripheral portion. That is, the angle α is non-negative.

  Furthermore, in the present embodiment, the above-described angle α is controlled to be plus including manufacturing errors and variations. Then, as shown in FIG. 6, it is possible to suppress a decrease in error rate in a region where the skew angle is close to zero.

  FIG. 6 shows the read error rate in the radial direction when the angle a is kept larger than 3 degrees and when the angle α is not controlled in the asymmetric roof tile recording method using a magnetic head having a rectangular main pole. It is a figure which shows position dependence.

  As can be seen from FIG. 6, when the angle α is kept larger than 3 degrees, it is possible to suppress a decrease in error rate in a region where the radial position is close to zero, that is, a region where the skew angle is close to zero. it can. The angle α is preferably 10 degrees or less.

  The reason for this will be described below. Even if the shape of the main magnetic pole at the ABS is rectangular or trapezoidal, when the angle α increases, the recorded magnetization transition region (for example, shown by the broken line 260 in FIG. Deviate from the crossing line 270. That is, the angle γ increases. The error rate is maximized when the magnetization transition region 260 crosses the track at 90 degrees.

  However, according to the simulation result shown in FIG. 12A, when the angle α is 10 degrees or less, the SN ratio is not significantly affected. That is, it is considered that when the angle α is 10 degrees or less, the SN ratio does not change so much and the error rate does not change so much. As described above, the angle α is preferably 10 degrees or less. The angle α is set using a method described later.

  7A and 7B show the results of measuring the recording density gain (ratio of recording density improvement with respect to Standard Condition (Condition # 1)) while changing various conditions. FIG. 7A is a diagram showing various conditions and recording density gain, and FIG. 7B is a diagram showing recording density gain under various conditions.

  As can be seen from FIGS. 7 (a) and 7 (b), by maintaining the rectangular main pole, the asymmetrical tile recording system, and the angle α to be positive as in the present embodiment, the inverted trapezoidal main pole is maintained. Compared with the conventional roof tile recording system of the symmetrical roof tile recording system, a remarkably high recording density gain can be obtained.

  Next, an example of the magnetic recording apparatus of this embodiment is shown in FIG.

  The above-described magnetic head according to the present embodiment can be incorporated into a recording / reproducing integrated magnetic head assembly and mounted on a magnetic recording / reproducing apparatus, for example. The magnetic recording apparatus according to the present embodiment may have only a recording function, but may have a reproducing function. In this case, the magnetic recording device is a magnetic recording / reproducing device. Hereinafter, the magnetic recording apparatus of the present embodiment will be described as a magnetic recording / reproducing apparatus.

  FIG. 8 is a schematic perspective view illustrating the configuration of the magnetic recording / reproducing apparatus according to the present embodiment. As shown in FIG. 8, the magnetic recording / reproducing apparatus 150 according to the present embodiment is a type of apparatus using a rotary actuator. In the figure, a magnetic disk 180 is mounted on a spindle motor 152 and rotated in the direction of arrow A by a motor (not shown) that responds to a control signal from a drive device control unit (not shown). The magnetic recording / reproducing apparatus 150 according to the present embodiment may include a plurality of magnetic disks 180.

  A head slider 153 that records and reproduces information stored in the magnetic disk 180 is attached to the tip of a thin-film suspension 154. Here, the head slider 153 mounts the magnetic head of the present embodiment near the tip thereof together with the magnetic shield.

  When the magnetic disk 180 rotates, the medium facing surface (ABS) of the head slider 153 is held with a predetermined flying height from the surface of the magnetic disk 180. The head slider 153 may be a so-called “contact traveling type” in which the head slider 153 contacts the magnetic disk 180.

  The suspension 154 is connected to one end of an actuator arm 155 having a bobbin portion for holding a drive coil (not shown). A voice coil motor 156, which is a kind of linear motor, is provided at the other end of the actuator arm 155. The voice coil motor 156 can be composed of a drive coil (not shown) wound around the bobbin portion of the actuator arm 155, and a magnetic circuit composed of a permanent magnet and a counter yoke arranged to face each other so as to sandwich the coil. .

  The actuator arm 155 is held by ball bearings (not shown) provided at two positions above and below the bearing portion 157, and can be freely rotated and slid by a voice coil motor 156.

  FIG. 9 illustrates a partial configuration of the magnetic recording / reproducing apparatus according to the present embodiment, and is an enlarged perspective view of the magnetic head assembly 160 ahead of the actuator arm 155 as viewed from the disk side.

  As shown in FIG. 9, the magnetic head assembly 160 includes a bearing portion 157, a head gimbal assembly (hereinafter referred to as HGA) 158 extending from the bearing portion 157, and a bearing portion 157 extending in the opposite direction to the HGA. And a support frame that supports the coil of the voice coil motor. The HGA includes an actuator arm 155 extending from the bearing portion 157 and a suspension 154 extending from the actuator arm 155.

  A head slider 153 including the magnetic head according to the present embodiment is attached to the tip of the suspension 154.

  That is, the magnetic head assembly 160 according to the present embodiment includes the magnetic head according to the present embodiment, a suspension 154 on which the magnetic head is mounted at one end, and an actuator arm 155 connected to the other end of the suspension 154. Yes.

  The suspension 154 has lead wires (not shown) for signal writing and reading, and the lead wires are electrically connected to the electrodes of the magnetic head incorporated in the head slider 153. An electrode pad (not shown) is provided on the magnetic head assembly 160.

  A signal processing unit 190 (not shown) that writes and reads signals to and from the magnetic disk 180 using a magnetic head is provided. The signal processing unit 190 is provided, for example, on the back side of the magnetic recording / reproducing apparatus 150 shown in FIG. Input / output lines of the signal processing unit 190 are connected to the electrode pads and are electrically coupled to the magnetic recording head.

  As described above, the magnetic recording / reproducing apparatus 150 according to the present embodiment is relatively relative to the magnetic disk 180, the magnetic head according to the present embodiment, and the magnetic disk and the magnetic head facing each other while being separated or in contact with each other. A movable part (movement control part) that can be moved to a position, a position control part for aligning the magnetic head with a predetermined recording position of the magnetic disk, and signal processing for writing and reading signals to and from the magnetic disk using the magnetic head A section. The movable part may include a head slider 153. In addition, the position control unit may include a magnetic head assembly 160.

  When the magnetic disk 180 is rotated, the actuator arm 155 is rotated by the voice coil motor 156 and the head slider 153 is loaded onto the magnetic disk 180, the medium facing surface (ABS) of the head slider 153 mounted on the magnetic head is the magnetic disk 180. It is held with a predetermined flying height from the surface. In this state, information recorded on the magnetic disk 180 can be read based on the principle described above.

  Next, a first setting method of the angle α will be described with reference to FIGS. 13 (a) and 13 (b). FIG. 13A is a perspective view of the head slider 153 and the suspension 154 for explaining an example of a method for setting the angle α. FIG. 13B is a plan view of the main magnetic pole 10 as seen from the magnetic disk 180. In FIG. 13B, the main magnetic pole according to the second embodiment, which will be described later, is shown as the main magnetic pole 10. However, the main magnetic pole of the first embodiment can be used similarly. The head slider 153 is mounted on the suspension 154 and joined, and the angle α is set at the time of joining. First, before the joining, the shape of the main magnetic pole 10 is confirmed using an AFM (Atomic Force Microscope) or an MFM (Magnetic Force Microscope). At this time, as shown in FIGS. 13A and 13B, an angle δ formed by a line 153b parallel to the center line 153a of the head slider 153 and the side 220 of the main magnetic pole 10 is measured. The angle α is calculated from the relationship between the angle δ and the skew angle of the magnetic disk 180, and the head slider 153 is joined onto the suspension 154 so that the angle α is non-negative. In FIG. 13B, reference numeral 20 denotes a shield.

  A second setting method of the angle α will be described with reference to FIGS. 14 (a) and 14 (b). FIG. 14A is a perspective view of the head slider 153 and the suspension 154 for explaining another example of the method for setting the angle α. FIG. 14B is a plan view of the main magnetic pole 10 as viewed from the magnetic disk 180. In FIG. 14B, the main magnetic pole of the second embodiment described later is shown as the main magnetic pole 10, but the same can be done using the main magnetic pole of the first embodiment. First, before joining the head slider 153 onto the suspension 154, the shape of the main magnetic pole 10 is confirmed using an AFM (Atomic Force Microscope) or an MFM (Magnetic Force Microscope). At this time, as shown in FIGS. 14A and 14B, an angle δ formed by a line 153b parallel to the center line 153a of the head slider 153 and the side 220 of the main magnetic pole 10 is measured. Subsequently, the rotary actuator 186 is mounted and joined to the region of the suspension 154 to which the head slider 153 is to be joined. Thereafter, the head slider 153 is mounted on the rotary actuator 186 and joined. The angle α is calculated from the relationship between the measured angle δ and the skew angle of the magnetic disk 180, and the rotation of the rotary actuator 186 is controlled so that the angle α is non-negative. The rotation of the rotary actuator 186 is electrically controlled by, for example, a signal processing unit 190 shown in FIG. When the rotation of the rotary actuator 186 is controlled so that the angle α is non-negative, the rotation operation of the rotary actuator 186 is fixed by the signal processing unit 190. In addition, in FIG.14 (b), the code | symbol 20 shows a shield.

  As described above, according to the present embodiment, it is possible to provide a magnetic recording apparatus that achieves a higher recording density by using the roof tile recording method.

(Second Embodiment)
A magnetic recording apparatus according to the second embodiment will be described with reference to FIGS. The magnetic recording device of this embodiment has a configuration in which the shape of the main magnetic pole at the ABS in the magnetic recording device of the first embodiment is trapezoidal as shown in FIGS. 10 (a) and 10 (b). Yes.

  That is, the main magnetic pole 10A according to the present embodiment has a shape in which the trailing edge width is narrower than the leading edge width in the ABS.

  An arrow 250 shown in FIG. 10A indicates the advancing direction (rotational direction) of the magnetic disk 180, and an arrow 240 shown in FIG.

  As in the second embodiment, the ABS of the main pole has a trapezoidal shape in which the leading edge is wider than the trailing edge, thereby further increasing the ABS main pole compared to the first embodiment. The area of can be taken wide. In a magnetic recording apparatus having a recording density of about 1 terabit per square inch: 500 kT / inch × 2100 kB / inch, the effective magnetic field is reduced to 6% by changing the bevel angle β shown in FIG. Can be increased. This is a gain of about 5% in terms of recording density when calculated by simulation.

  However, in the case where the rectangular main magnetic pole is used as in the first embodiment, if the skew angle of the magnetic head is set to about 0 degrees on the inner periphery, the angle α described above can be obtained as shown in FIG. Become negative. This creates a write area with poor quality in the outer peripheral direction and lowers the error rate.

As shown in FIG. 10B, when the trapezoidal main pole is used, the angle α is minimized at the innermost periphery. At this time, it is preferable that α> 0 at all radial positions.
In this case, the skew angle of the magnetic head at the inner periphery is 10 degrees or more, so it is further increased at the outer periphery and is approximately 30 degrees at the outermost periphery.

  Therefore, there is a drawback that the skew angle at the outer peripheral portion becomes large, which causes a decrease in the reading error rate. From this point of view, the bevel angle β of the trapezoidal main pole is preferably 10 degrees or less. This bevel angle is an angle formed by one leg, which is a side different from the leading edge and trailing edge in the ABS of the main pole, and a perpendicular line extending from the end point of the trailing edge to the leading edge.

  The second embodiment can provide a magnetic recording apparatus that can achieve a higher recording density than the first embodiment.

(Third embodiment)
A magnetic recording apparatus according to the third embodiment will be described.

  Consider a case where the writing direction in the roof tile recording method is recorded asymmetrically from the outer periphery to the inner periphery. If the inner periphery skew angle is 3 degrees, the outermost skew angle of a 2.5 inch hard disk usually exceeds 20 degrees. Even when the angle α is kept positive, if the absolute value of the skew angle is increased, the performance is deteriorated. Therefore, in particular, when employing asymmetric recording, it is effective to suppress the fluctuation of the skew angle. This can be achieved, for example, by increasing the length of the head arm portion.

  In this way, by using the technology for increasing the length of the head arm portion, the length of the arm portion is increased within the range of the current 2.5-inch hard disk device, so that the fluctuation of the skew angle is 2 at the maximum. Can be suppressed within degrees.

  A magnetic head having a trapezoidal main magnetic pole with a bevel angle β of 10 degrees is measured with a normal 2.5 inch skew angle fluctuation, and the skew angle fluctuation is kept at 5 degrees using a long arm. FIG. 11 shows the result of comparison of the read error rates at that time.

  As can be seen from FIG. 11, in the normal skew angle design, the error rate at the outermost periphery is 1.5 orders of magnitude worse than the innermost periphery, but the error rate is degraded at the outermost periphery by using a long arm. Can almost prevent.

  In the present embodiment, the magnetic recording apparatus of the second embodiment is configured to include a mechanism that suppresses fluctuations in the skew angle.

  As in the second embodiment, the third embodiment can also provide a magnetic recording apparatus that can achieve higher recording density.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

10 Main pole 20a Leading shield 20b Trailing shield 20c, 20d Side shield 30 Return yoke 40 Coil 160 Magnetic head assembly 180 Magnetic recording medium (magnetic disk)
210 Main pole 220 Edge line of main pole 230 Edge line of track

Claims (7)

A magnetic disk;
A main pole having a medium facing surface facing the magnetic disk, wherein a width of a leading edge of the main pole on the medium facing surface is substantially the same as a width of a trailing edge of the main pole on the medium facing surface. The main pole,
A magnetic head having a magnetic head on which the main magnetic pole is mounted, a head slider on which the magnetic head is mounted, a suspension to which the head slider is joined at one end, and an actuator arm mounted at the other end of the suspension. A head assembly;
With
Overwriting in one direction from the inner periphery to the outer periphery of the magnetic disk,
A magnetic recording apparatus having a skew angle of 2.5 degrees or less.   The magnetic recording apparatus according to claim 1, wherein the skew angle is −16 degrees or more.   The magnetic recording apparatus according to claim 1, wherein the skew angle is −10 degrees or more.   The magnetic head assembly includes a boundary line between a track on which writing is performed and a track adjacent to the track and in a direction opposite to the writing direction, and the main magnetic pole on a side opposite to the writing direction on the medium facing surface. The head slider and the suspension are joined such that the angle α is non-negative when an angle α formed with the side of the head is a positive angle in a direction from the boundary line toward the side. Item 4. The magnetic recording device according to any one of Items 1 to 3.   The magnetic recording apparatus according to claim 1, wherein the main pole has a substantially rectangular shape on the medium facing surface.   6. The magnetic recording apparatus according to claim 1, further comprising a rotary actuator provided between the head slider and the suspension.   The magnetic recording apparatus according to claim 1, further comprising a reproducing unit that reads information from the magnetic disk.

Images