JP2005085401A - Magnetic head and magnetic recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize high-density recording and DC erase suppression. <P>SOLUTION: This magnetic head is equipped with: a main magnetic pole 10a of which the recording track width W which appears on a medium running face is ≤100 nm and the ratio of the throat height H to the width W, R=H/W, is ≥1; and soft magnetic guides 12 consisting of a soft magnetic material whose saturation magnetic flux density is lower than that of the main magnetic pole and which are disposed at both sides in the track width direction of the main magnetic pole. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic head and a magnetic recording / reproducing apparatus.

  In recent years, in order to cope with a rapid increase in magnetic recording density in a hard disk drive, there is a demand for a rapid decrease in recording track width. In the era of hundreds of Gbits per square inch (hundreds of Gigabits per square inch), perpendicular magnetic recording uses a magnetic material having a saturation magnetic flux density (Bs) of 2T or more, and the recording track width is zero. It is expected to be 1 μm or less. Thus, in order to form a narrow track with a high saturation magnetic flux density material in the main magnetic pole, there are problems of DC erase and manufacturing yield. In DC erase, the magnetization of the main pole faces the medium running surface due to the influence of the demagnetizing field caused by the magnetization generated on the side surface of the magnetic pole due to the narrowing of the track, and as a result, the head runs due to the magnetization directed to the medium running surface. This is a phenomenon in which medium writing or erasing occurs. It has been reported that this DC erase occurs (see, for example, Non-Patent Document 1). In particular, in the case of a magnetic head having a main pole in which the recording track width W appearing on the medium running surface is 100 nm or less and the ratio R = H / W to the throat height H is 1 or more, the magnetization of the main pole is in the direction of the medium running surface. Easy to face.

  Although it is necessary for the magnetization of the main pole to be directed in the width direction of the main pole in order to prevent DC erase, it is directed toward the medium running surface due to the influence of the demagnetizing field. As a measure for preventing the magnetization of the main pole from facing the direction of the medium traveling surface, it is necessary to reduce the length to the medium traveling surface (hereinafter referred to as the throat height). Reducing the throat height can be realized by strictly controlling the machining length in the depth machining process, but the throat height in the depth machining process is balanced with the positional displacement relationship with the reproducing element and the depth machining accuracy. The problem of an increase in cost is unavoidable in reducing this.

  Another measure is to apply a structure that physically provides magnetization stabilization by providing a bias means for the main magnetic pole. This strategy is found in the playhead. For example, in the case of a magnetoresistive (MR) reproducing element, a bias structure that magnetizes and fixes both sides of the MR film is used. They have a structure in which a bias film is formed by being laminated on an MR film, or a structure in which a bias film made of a hard magnetic material is provided on both sides of the MR film. What is important in the bias structure of these read heads is that the MR film stacked on or adjacent to the bias film must never move so as not to pick up a read signal from another track. In an MR element, particularly a GMR element that is generally used at present, a magnetization free layer (hereinafter also referred to as a free layer) that senses a signal magnetic field is as thin as 10 nm or less.

  On the other hand, when this bias structure is applied to a recording head, since the thickness of the main pole is generally about 100 nm, it is necessary to form a hard magnetic body to be biased on the order of several hundred nanometers to several microns, and leakage magnetic flux However, since the soft magnetic deterioration of the shield due to the inflow of the read shield, the influence on the read resolution deterioration, and the apparent deterioration of the main magnetic pole soft magnetism occur, it is necessary to increase the coil excitation, which is not practical. Therefore, a practical main pole bias structure is necessary.

  Further, the main magnetic pole is formed with the same track width in the throat height direction so-called straight line so that the track width does not change by depth polishing. Therefore, if the throat height is large, the magnetic flux leaks out of the main pole from the middle, and sufficient magnetic flux cannot be supplied to the main magnetic pole surface. This is due to the fact that the conductance of the main pole is extremely low because the main pole is formed of a thin wire. In order to prevent this, a structure in which a low saturation magnetic flux density material and a high saturation magnetic flux material are laminated like a MIG (Metal In Gap) head has been proposed. However, stacking in the film thickness direction increases the amount of magnetization generated at the edge in the magnetic pole width direction, and further, the magnetization becomes difficult to face in the track width direction.

There is also a problem as a recording / reproducing apparatus. The track density, which is one of the factors that determine the recording density, is mainly defined by the track width of the recording head. However, when the recording track is 100 nm or less, the dimensional tolerance is 10 nm (± 5 nm) or less. When leaving an isolated pattern such as a recording head, it is possible to have a post-process dimension that is less than the dimension specified by photolithography or EB (Electron Beam) lithography, but the track width tolerance is Because it is determined by tolerances, it cannot be brought below the lithography system limit. Tolerance issues mean yield loss. In addition, assuming that the guard band obtained by subtracting the track width from the track pitch is about 10% of the track width (10 nm or less), positioning accuracy of that accuracy is required, so that high-speed seek and track following are difficult. Therefore, when viewed as a recording / reproducing apparatus, in a system in which the recording density is determined by the track width of a conventional recording head, the demand for the track width and positioning accuracy of 10 nm or less causes an increase in cost due to a decrease in recording head yield, high-speed response, etc. Have problems.
Nakamoto et al .: Journal of Japan Society of Applied Magnetics, Vol.27, No.3 (2003) pp124-128

  In a high recording density hard disk drive of several hundred Gbpsi or more, when the track width is reduced, the recording magnetic field is reduced due to the problem of DC erase due to the magnetization of the main pole facing the medium running surface and the decrease in main pole conductance. In addition, the track width tolerance becomes small, causing problems such as a decrease in manufacturing yield and difficulty in high-speed response due to a small head positioning tolerance.

  The present invention has been made in view of the above circumstances, and it is a network to provide a magnetic head and a magnetic recording / reproducing apparatus that can perform high-density recording and suppress DC erasure.

  The magnetic head according to the first aspect of the present invention includes a main magnetic pole having a recording track width W appearing on the medium running surface of 100 nm or less and a ratio R = H / W to a throat height H of 1 or more; A soft magnetic guide made of a soft magnetic material having a saturation magnetic flux density lower than that of the main magnetic pole is provided on both sides in the track width direction.

  A nonmagnetic film may be provided between the main magnetic pole and the soft magnetic guide.

  Note that a soft magnetic layer made of a material having a lower saturation magnetic flux density than the main magnetic pole may be provided in the bit length direction of the main magnetic pole.

  According to a second aspect of the present invention, there is provided a magnetic recording / reproducing apparatus comprising a recording medium having a recording track defined by a nonmagnetic material and the magnetic head described above.

  The width of the main magnetic pole is preferably 50% or more of the track width on the recording medium.

  The width of the main magnetic pole may be substantially equal to the track width on the recording medium.

  The width W of the main magnetic pole of the magnetic head is equal to or greater than L when the distance L between the center of gravity of the magnetic particles at the left and right ends of the magnetic particles constituting one bit on the recording medium in the track width direction. It is preferable.

  According to the present invention, high-density recording is possible and DC erase can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
A magnetic head according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the magnetic head according to the present embodiment as viewed from the medium traveling surface, FIG. 2 is a sectional view of the magnetic head according to the present embodiment in the depth direction, and FIG. 3 is a perspective view of the magnetic head according to the present embodiment from the medium traveling surface. It is a figure. The magnetic head according to this embodiment includes a return yoke 2, an insulating layer 6 formed on the return yoke 2, a coil 4 embedded in the insulating layer 6, and a back core formed at the center of the coil 4. 8, a main magnetic pole 10a formed on the coil 4 via the insulating layer 6, a soft magnetic guide 12 formed on both sides of the main magnetic pole 10a in the track width direction, and on the main magnetic pole 10a and the soft magnetic guide 12 And an auxiliary yoke 14 formed on the surface.

  In the present embodiment, the medium facing surfaces of the return yoke 2, the insulator 6, the main magnetic pole 10 a, and the soft magnetic guide 12 are on the same plane (medium traveling surface) 18. The main magnetic pole 10a preferably has a width W of 100 nm or less and an aspect ratio R (= H / W) with the throat height H of 2 or more. The soft magnetic guide 12 formed on both sides of the main magnetic pole 10a is made of a material having a lower saturation magnetic flux density than the main magnetic pole 10a, and the volume of the soft magnetic guide 12 is preferably larger than that of the main magnetic pole 10a.

Next, the manufacturing process of the magnetic head according to the present embodiment will be explained with reference to FIGS.
First, an alumina undercoat film (not shown), a lower shield film (not shown), and a lower gap film (not shown) are formed on an AlTiC substrate (not shown), and MR reproduction is performed on the lower gap film. An element (not shown) is formed, an upper gap film (not shown) is formed so as to cover the element, and a permalloy (NiFe alloy) film (shown in the figure) serving as an upper shield and a return yoke is formed on the upper gap film. 2 μm is formed. An exciting coil surrounded by an insulating layer is formed on the permalloy film, and a back core made of permalloy is formed at the center of the coil. A main magnetic pole film 10 made of an FeCoNi alloy is formed thereon with a thickness of about 0.1 μm (see FIG. 4). The main magnetic pole film 10 has a saturation magnetic flux density Bs of 2.3T.

  Next, a T-type resist pattern 20 having a width of about 50 nm is formed on the main magnetic pole film 10 by using a lithography technique (see FIG. 5). Using this T-type resist pattern 20 as a mask, ion milling is performed to remove the main magnetic pole film 10 other than that covered with the T-type resist pattern 20 to form the main magnetic pole 10a (see FIG. 6).

Subsequently, a soft magnetic guide film 12 made of permalloy is formed to a thickness of about 0.1 μm (see FIG. 7), and the permalloy film 12 is adjacent to both sides of the main magnetic pole 10a by further lifting off. Further, the same process shown in FIGS. 5 to 7 is performed on the permalloy film 12 to form an insulating film adjacent to the permalloy film 12 on both sides. Then, as shown in FIG. 8, a soft magnetic guide 12 having a width of 0.3 μm sandwiches both sides of a main magnetic pole 10a having a track width W of 50 nm, and further, a width of about 0.1 μm is placed on both sides of the soft magnetic guide 12. A structure sandwiched between insulating films 13 made of SiO ₂ can be obtained. Thereafter, an auxiliary yoke 14 having a thickness of about 2 μm is formed at a position recessed by about 100 nm from the medium running surface 18 so as to cover the main magnetic pole 10a and the soft magnetic guide 12 (see FIGS. 1 and 2).

  In the magnetic head thus formed, the main magnetic pole 10a extends to the back core 8 by about 7 μm. Further, the auxiliary yoke 14 is laminated by recessing about 100 nm from the medium running surface 18. The medium running surface 18 has a configuration in which a main magnetic pole 10a having a width of 50 nm and soft magnetic guides 12 having a width of about 0.3 μm are provided on both sides thereof. Below that, a return yoke / upper shield 2 is formed via an insulator 6.

  Such a magnetic head was manufactured, and it was run on a continuous medium made of a FePt film having a coercive force of 10 kOe without inputting a recording signal. Thereafter, the output was measured with an MR reproducing head. When the magnetic head having the structure of this embodiment was used, no DC erase was confirmed. Further, from the measurement result of the microtrack profile, the recording track width was about 50 nm, and recording from the soft magnetic guide 12 was not confirmed.

  On the other hand, a magnetic head having a structure without soft magnetic guides on both sides was produced as a comparative example, and was run in the same manner to evaluate the output. In the case of this comparative example, an average power reduction of 15% was confirmed.

  From the above, it can be seen that the magnetic head according to the present embodiment can suppress DC erase. The soft magnetic guide 12 also serves as an auxiliary yoke. Therefore, the magnetic flux does not leak even at a longer throat height and is supplied to the tip of the main magnetic pole 10a. As a result, the magnetic field generated from the main magnetic pole 10a does not decrease compared to the comparative example without the soft magnetic guide 12. Therefore, the machining margin in the depth machining process can be increased, and as a result, the machining yield can be increased and the manufacturing cost can be reduced.

  Further, the positional relationship among the main magnetic pole 10a, the auxiliary yoke 14, and the return yoke 2 is not limited to the case of the present embodiment, and may be configured as shown in FIG. That is, the length of the main magnetic pole 10a in the depth direction is shorter than that of the first embodiment, but the main magnetic pole 10a and the soft magnetic guides 12 on both sides thereof are in contact with the auxiliary yoke 14. ing. In this case, the same effect as the first embodiment can be obtained.

  Further, as shown in FIG. 10, the same effect can be obtained even if the positions are switched so that the arrangement relationship between the return yoke 2 and the auxiliary yoke 14 of the magnetic head shown in FIG. 9 is reversed. Further, as shown in FIG. 11, the same effect can be obtained even if the positions are switched so that the arrangement relationship between the return yoke 2 and the auxiliary yoke 14 of the magnetic head according to the present embodiment shown in FIG. 2 is reversed.

(Second Embodiment)
Next, a magnetic head according to a second embodiment of the invention will be described with reference to FIG. FIG. 12 is a view of the magnetic head according to the present embodiment as viewed from the medium running surface. The magnetic head according to the present embodiment is similar to the magnetic head according to the first embodiment shown in FIG. 3 except that the nonmagnetic film 11 is provided between the main magnetic pole 10a and the soft magnetic guide 12 and between the insulating layer 6 and the soft magnetic guide 12. It is the provided structure.

  In the magnetic head manufacturing method according to this embodiment, in the first embodiment, before the soft magnetic film 12 made of permalloy is formed in the manufacturing process of the main magnetic pole 10a and the soft magnetic guide 12 shown in FIG. A nonmagnetic film 11 made of 5 nm is formed. Otherwise, the manufacturing process is the same as in the first embodiment.

  In the magnetic head according to the present embodiment, the nonmagnetic film 11 is inserted between the main magnetic pole 10 a and the soft magnetic guide 12. With such a configuration, it is possible to cut the exchange coupling with the soft magnetic guide 12 having a large volume while reducing the influence of the demagnetizing field generated in the main magnetic pole 10a. The magnetic pole 10a and the soft magnetic guide 12 can easily operate independently.

  Unlike the present embodiment, when the main magnetic pole 10a and the soft magnetic guide 12 are exchange coupled, it is necessary to move the entire soft magnetic guide 12 to move the magnetization of the main magnetic pole 10a. Therefore, a large excitation current is required.

  On the other hand, when the exchange coupling is cut and the main magnetic pole 10a and the soft magnetic guide 12 are moved close to each other independently as in this embodiment, the product of the volume of the main magnetic pole and the saturation magnetic flux density is Since it is smaller than that of the soft magnetic guide, it can be moved with a smaller exciting current. Therefore, it is suitable for higher frequency recording. By selecting a fcc structure film such as Ta as the nonmagnetic film 11, the crystallinity of the soft magnetic guide 12 can be improved, and the soft magnetism can be improved. As a result, a head having a good excitation magnetic field response can be supplied.

  The soft magnetic guides 12 are arranged not only on both sides of the main magnetic pole 10a but also below the main magnetic pole 10a as shown in FIG. 13 or above and below the main magnetic pole 10a as shown in FIG. The soft magnetic guide 12 can further exhibit the effect as an auxiliary yoke as compared with the second embodiment. Therefore, the soft magnetic guide 12 increases the magnetic flux conductance of the main magnetic pole 10a, and can reduce the decrease in the amount of magnetic flux supplied to the tip of the main magnetic pole 10a. Recording efficiency can be increased. Further, the depth processing margin can be widened and the manufacturing cost can be reduced. 13 and 14, a nonmagnetic film (not shown) is provided between the main magnetic pole 10 a and the soft magnetic guide 12.

  FIG. 15 shows a top view when the soft magnetic guide 12 of the magnetic head of this embodiment is recessed by 20 nm from the tip of the magnetic pole. In the magnetic head having this configuration, in the process shown in FIG. 7 of the first embodiment, the medium travels by the FIB (Focused Ion Beam) 25 as shown in FIG. 16, with the soft magnetic film 12 made of permalloy formed. Etching is performed from the surface 18 to a depth of 20 nm and a width of 0.3 μm, and thereafter, the same process as the manufacturing process of the first embodiment is performed. By recessing from the medium running surface 18 in this way, there is an effect of preventing the magnetic flux flowing from the soft magnetic guide 12 to the recording medium from being recorded on the recording medium. In particular, when performing high-frequency recording, it is possible to suppress the necessary recording magnetic field generated from the magnetic head by setting the coercive force of the recording medium to be low, the excitation current can be reduced, and it is easy to cope with high frequencies. Become. In this way, the soft magnetic guide 12 is not exposed to the medium running surface 18 but is recessed about 20 nm from the running surface, thereby controlling the magnetization of the main magnetic pole 10a and preventing the DC erase and maintaining the effect as an auxiliary yoke. Therefore, it is possible to suppress writing blur from the soft magnetic guide 12 by reducing the coercive force setting of the recording medium without reducing the generation of the magnetic field from the main magnetic pole 10a. With such a structure, it is possible to provide a magnetic head capable of coping with high frequency and high density recording (that is, narrow track width).

  Next, as shown in FIG. 17, the recording medium is a patterned medium 50 in which, for example, FePt material is patterned into rectangular dots 52 having a width of 50 nm and a length of 25 nm and embedded in an insulator 54. The experimental results for DC erase suppression and writing blur suppression to adjacent tracks in the case of The patterned medium 50 and a recording head are combined, recording is performed by changing the width (head track width) of the main magnetic pole 10a, and after recording, recording dots are observed by MFM (Magnetic Force Microprobe) to write and read. The required recording bit width (bit track width) was obtained. FIG. 18 is a cross-sectional view in the track longitudinal direction showing the outline of this experiment. FIG. 19 shows a graph of the dependency of the recording bit width on the width of the main magnetic pole 10a obtained from this experiment. As can be seen from FIG. 19, the width of the dot 52 is 50 nm, but when the head track width is 20 nm, it is not observed as a bit, and from 30 nm or more, the magnetization reversal occurs all at once, and the physically defined dot width, that is, Observed as a 50 nm recording bit.

  Therefore, when the recording medium is a continuous medium, the recording head determines the track width, that is, the recording density, but when the recording medium is a patterned medium, the dot shape / density determines the recording density. Therefore, it is understood that it is sufficient for the patterned media to have a head track width that exceeds a certain range. This has a great advantage over the dimensional tolerance of the head track width. Even when the patterned medium is combined with the magnetic head described in the first or second embodiment, it is possible to obtain the effects described in the first or second embodiment such as suppression of DC erase or increase in conductance. Note that when the head is on the inner week or the outer periphery of the medium, the height component of the recording main pole (height h in FIGS. 1 and 10a) appears in the track width due to the yawing angle of the head, and the write width increases. There is. In the case of patterned media, the influence of the height component of the main pole can be allowed by configuring the track width on the recording medium so as to become smaller and larger from the outer circumference to the inner circumference in advance. .

  Next, using the patterned medium 50 shown in FIG. 17 and a FePt medium that can be recorded if the head track 10a and the dot 52 overlap by 50% or more, the target track with respect to the off-track amount. An experiment was conducted to determine the recording characteristics of the target track on the adjacent track. In this experiment, FePt material was patterned into rectangular dots with a width of 50 nm and a length of 25 nm, and the patterned medium 50 in which the distance between the dots was set to 5 nm was combined with the recording head, and the head was off-tracked using the width of the main pole 10a as a parameter. Recording was performed, and after recording, the recording dots were observed by MFM to determine the recording bit width.

  FIG. 20 is a cross-sectional view in the track width direction showing the outline of this experiment. In the figure, track-1 is an adjacent track in the -direction, track 1 is an adjacent track in the + direction, and track 0 is an original track. As shown in FIG. 20, the off-track amount represents the distance from the center line of the target track to the center line of the head track (center line of the main pole).

  In this experiment, three types of magnetic heads with head track widths of 70 nm, 50 nm, and 30 nm were prepared. FIG. 21 shows the experimental results when the head track width is 70 nm. In this case, the margin of track 0 is ± 30 nm, but it can be seen that there is a margin of ± 10 nm as an off-track at the time of recording from the writing on tracks −1 and +1.

  The experimental results when the head track width is 30 nm are shown in FIG. In this case, there is a margin of ± 40 nm for writing on adjacent tracks, but ± 10 nm for track 0. Therefore, when the head track is narrower than the dot width, the original track (track 0) determines the allowable limit of the track position deviation.

  Further, as shown in FIG. 23, when the head track width (50 nm) and the dot track width (50 nm) are equal, the recording characteristics to the original track (track 0) further shift to the adjacent tracks (track-1, +1). It can be seen that there is a margin of ± 20 nm.

  Therefore, when the guard band width (distance between dots) is as small as about 10% of the dot track width, making the dot track width and the head track width substantially equal increases the margin for the overall alignment. I understand that.

Next, as shown in FIG. 24, an experimental result in the case where a patterned medium 50 in which a plurality of dots 52 are arranged in the track width direction to form one bit will be described. In FIG. 24, the number N of dots 52 constituting one bit is two. As shown in FIGS. 25A and 25B, the patterned medium 50 used in the experiment has the dots 52 ₁ and 52 ₂ made of FePt material having a diameter d of about 25 nm through the insulating layer 54 made of SiO _2. This is a patterned medium in which two are arranged as one recording bit. Note that the distance between the dots 52 ₁ and 52 _{2 serving as} one recording bit is 1 nm. FIG. 25A is a cross-sectional view of the patterned medium in the track width direction, and FIG. 25B is a plan view of the patterned medium.

An experiment similar to that described above was performed using the patterned media shown in FIG. The space between bits was 5 nm. First, using a head with a head track width of 70 nm, as shown in FIGS. 25A and 25B, the recording head (main magnetic pole 10a) is gradually overlapped with the dots 52, and the bit width thereafter is set to MFM. Observed. FIG. 26 is a graph showing the dependency of the recording bit on the overlap amount. As can be seen from Figure 26, the main magnetic pole 10a and the dot 52 will overlap, the overlap amount reaches more than half of the first dot 52 _first diameter (50 nm), First one dot magnetization reversal. Further overlapping amount increases, the dots 52 ₂ where the more than half overlap with another dot 52 ₂ is the magnetization reversal, 50 nm recording bits is observed. In other words, it can be seen that when the dot overlaps more than half, magnetization is reversed and recording is performed. Therefore, the minimum value of the head track width required for writing 1 bit is the half of the magnetic particles present on the right side to the half of the magnetic particles on the left side among the plurality of magnetic particles constituting 1 bit in the track width direction. It becomes the value which overlaps. Since the magnetic particle shape is generally symmetrical with respect to the track width direction, the head track width W is the distance L between the center of gravity of the magnetic particles at the left and right ends of the magnetic particles constituting one bit in the track width direction. Then, W is L or more.

  Further, in order not to cause writing blur on the adjacent track, it is assumed that the average particle diameter of dots viewed in the track width direction is D, and the guard band distance between tracks is G. W <(track width + 2G + 2 (D / 2)) It becomes. Track width 50 nm (When the number of magnetic particles N = 2, D = 25, G = 5 in the track width direction is included, 37.5 <W <85 (nm), and the track width tolerance of the recording head increases. I understand that.

(Third embodiment)
Next explained is a magnetic recording / reproducing apparatus according to the third embodiment of the invention. The recording heads according to the first and second embodiments described with reference to FIGS. 1 to 25 are incorporated into a recording / reproducing integrated magnetic head assembly and can be mounted on a magnetic recording / reproducing apparatus, for example.

  FIG. 27 is a main part perspective view illustrating a schematic configuration of such a magnetic recording / reproducing apparatus. That is, the magnetic recording / reproducing apparatus 150 according to the present embodiment is an apparatus using a rotary actuator. In the figure, a magnetic disk 200 for longitudinal recording or perpendicular recording is mounted on a spindle 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 disk 200 has a recording layer for longitudinal recording or perpendicular recording. In the magnetic disk 200, a head slider 153 that records and reproduces information stored in the magnetic disk 200 is attached to the tip of a thin film suspension 154. Here, the head slider 153 mounts the magnetic head according to any of the above-described embodiments near the tip thereof.

  When the magnetic disk 200 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 200.

  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 is 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 so as to sandwich the coil.

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

  FIG. 28 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. That is, the magnetic head assembly 160 has an actuator arm 151 having, for example, a bobbin portion that holds a drive coil, and a suspension 154 is connected to one end of the actuator arm 155.

  A head slider 153 including any of the magnetic heads described above is attached to the tip of the suspension 154. A reproducing head may be combined. The suspension 154 has a lead wire 164 for writing and reading signals, and the lead wire 164 and each electrode of the magnetic head incorporated in the head slider 153 are electrically connected. In the figure, reference numeral 165 denotes an electrode pad of the magnetic head assembly 160.

1 is a perspective view showing the configuration of a magnetic head according to a first embodiment of the invention. FIG. 3 is a cross-sectional view in the depth direction of the magnetic head according to the first embodiment. The figure which looked at the magnetic head by 1st Embodiment from the medium running surface. FIG. 5 is a perspective view showing a manufacturing process of the magnetic head according to the first embodiment. FIG. 5 is a perspective view showing a manufacturing process of the magnetic head according to the first embodiment. FIG. 5 is a perspective view showing a manufacturing process of the magnetic head according to the first embodiment. FIG. 5 is a perspective view showing a manufacturing process of the magnetic head according to the first embodiment. FIG. 5 is a perspective view showing a manufacturing process of the magnetic head according to the first embodiment. Sectional drawing of the depth direction of the magnetic head by the 1st modification of 1st Embodiment. Sectional drawing of the depth direction of the magnetic head by the 2nd modification of 1st Embodiment. Sectional drawing of the depth direction of the magnetic head by the 3rd modification of 1st Embodiment. The perspective view which shows the structure of the magnetic head by 2nd Embodiment of this invention. The figure which shows the structure of the magnetic head by the 1st modification of 2nd Embodiment. The figure which shows the structure of the magnetic head by the 2nd modification of 2nd Embodiment. The figure which shows the structure of the magnetic head by the 3rd modification of 2nd Embodiment. The perspective view which shows the manufacturing process of the magnetic head by the 3rd modification of 2nd Embodiment. The top view explaining the structure of an example of a patterned media. Sectional drawing of the track longitudinal direction which shows the outline | summary of the experiment using patterned media. The graph which shows the dependence of the width | variety of the main pole of a recording bit width. Sectional drawing of the track longitudinal direction which shows the outline | summary of the experiment using patterned media. The graph which shows the recording off-track dependence of the recording bit width when the head track width is 70 nm. The graph which shows the recording off-track dependence of the recording bit width when the head track width is 30 nm. 6 is a graph showing the recording off-track dependency of the recording bit width when the head track width is 50 nm. The top view explaining the structure of the other example of patterned media. Sectional drawing of the track longitudinal direction which shows the outline | summary of the experiment using patterned media. The graph which shows the overlap width dependence of recording bit width. FIG. 2 is a perspective view of a main part showing a schematic configuration of a magnetic recording / reproducing apparatus. The enlarged perspective view which looked at the magnetic head assembly ahead from an actuator arm from the disk side.

Explanation of symbols

2 Return yoke 4 Coil 6 Insulating film 8 Back core 10 Main magnetic pole film 10a Main magnetic pole 11 Nonmagnetic film 12 Soft magnetic guide 14 Auxiliary yoke 18 Medium running surface

Claims (7)

A main pole having a recording track width W appearing on the medium running surface of 100 nm or less and a ratio R = H / W to a throat height H of 1 or more;
A soft magnetic guide made of a soft magnetic material having a saturation magnetic flux density lower than that of the main magnetic pole on both sides in the track width direction of the main magnetic pole;
A magnetic head comprising:   2. The magnetic head according to claim 1, wherein a nonmagnetic film is provided between the main pole and the soft magnetic guide.   3. The magnetic head according to claim 1, wherein a soft magnetic layer made of a material having a lower saturation magnetic flux density than the main magnetic pole is provided in the bit length direction of the main magnetic pole.   A magnetic recording / reproducing apparatus comprising: a recording medium having a recording track defined by a nonmagnetic material; and the magnetic head according to claim 1.   5. The magnetic recording / reproducing apparatus according to claim 4, wherein the width of the main magnetic pole is 50% or more of the track width on the recording medium.   6. The magnetic recording / reproducing apparatus according to claim 5, wherein the width of the main magnetic pole is substantially equal to the track width on the recording medium.   The width W of the main pole of the magnetic head is such that W is equal to or greater than L when the distance L between the center of gravity of the magnetic particles at the left and right ends of the magnetic particles constituting one bit on the recording medium in the track width direction. The magnetic recording / reproducing apparatus according to claim 4, wherein:

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