JP2006147058A - Thin film magnetic head and magnetic recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film magnetic head in which erasure of information without intention at non-recording time can be suppressed. <P>SOLUTION: In the thin film magnetic head, a main magnetic pole layer 10 is constituted so that the front main magnetic pole layer part 10A which is extended to a position P1 in the rear from an air bearing surface 40, while which includes a tip part 10A1 having fixed width W1 prescribing recording track width of a recording medium, and the rear magnetic pole layer part 10B which is separated from the front main magnetic pole layer part 10A by being extended to the rear from a position P2 retreated more than the position P1, while which has larger width W4 more than the fixed width W1 of the tip part 10A1 out of the front main magnetic pole layer part 10A are included. Magnetic section structure of the front main magnetic pole lager part 10A is made appropriate so that needless magnetic fluxes are hard to leak at non-recording time based on shape magnetic anisotropy of the front main magnetic pole layer part 10A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thin film magnetic head provided with at least an inductive magnetic transducer for recording, and a magnetic recording apparatus equipped with the thin film magnetic head.

  In recent years, for example, with the improvement of the surface recording density of a magnetic recording medium such as a hard disk (hereinafter simply referred to as “recording medium”), an improvement in the performance of a thin film magnetic head mounted in a magnetic recording apparatus such as a hard disk drive is required. ing. As a recording method of this thin film magnetic head, for example, a longitudinal recording method in which the direction of the signal magnetic field is set in the in-plane direction (longitudinal direction) of the recording medium, or a direction of the signal magnetic field is set in a direction orthogonal to the surface of the recording medium. A perpendicular recording method is known. At present, the longitudinal recording method is widely used, but considering the market trend accompanying the improvement of the surface recording density of recording media, it is assumed that the perpendicular recording method will be promising instead of the longitudinal recording method in the future. Is done. This is because the perpendicular recording method can provide an advantage that a high linear recording density can be secured and a recorded recording medium is hardly affected by thermal fluctuation.

  The perpendicular recording type thin film magnetic head mainly includes a thin film coil for generating a magnetic flux for recording and a recording medium that extends backward from the air bearing surface and releases the magnetic flux generated in the thin film coil. A pole layer that generates a magnetic field for magnetizing in a direction perpendicular to the surface. In this perpendicular recording type thin film magnetic head, when a magnetic flux for recording is generated by energizing the thin film coil, a magnetic field for recording (vertical magnetic field) is generated by releasing the magnetic flux from the tip of the pole layer. The surface of the recording medium is magnetized based on the perpendicular magnetic field. Thereby, information is magnetically recorded on the recording medium.

Regarding the structure of this perpendicular recording type thin film magnetic head, several structural examples have already been proposed. Specifically, for example, a thin film magnetic head having a structure in which a large volume yoke layer is laminated on the magnetic pole layer in order to supplement the magnetic flux capacity (so-called magnetic volume) of the magnetic pole layer is known. (For example, refer to Patent Documents 1 and 2.)
JP 2002-197613 A JP 2004-164715 A

  By the way, in order to ensure the operating characteristics of a perpendicular recording type thin film magnetic head, it is necessary to suppress unintentional erasure of information during non-recording, for example. This “unintentional erasure of information at the time of non-recording” means that it remains in the magnetic pole layer at the time of non-recording, that is, in a state where the thin film coil is not energized (a state where no recording magnetic flux is generated). This is a problem in recording performance in which information recorded on the recording medium is erased unintentionally due to leakage of magnetic flux (residual magnetization) from the air bearing surface. However, in the conventional thin film magnetic head, since sufficient measures are not taken from the viewpoint of suppressing unintentional erasure of information at the time of non-recording, there is still room for improvement in that viewpoint. That is, in order to ensure the operating characteristics of a perpendicular recording type thin film magnetic head, it is desired to establish a technique capable of suppressing unintentional erasure of information during non-recording.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a thin film magnetic head capable of suppressing unintentional erasure of information at the time of non-recording, and a magnetic on which the thin film magnetic head is mounted. It is to provide a recording apparatus.

  A thin-film magnetic head according to the present invention emits a magnetic flux generated in a thin-film coil that extends backward from a thin-film coil that generates magnetic flux and a recording-medium facing surface that faces a recording medium moving in the medium traveling direction. A main magnetic pole layer for generating a magnetic field for magnetizing the recording medium in a direction perpendicular to the surface thereof, the main magnetic pole layer extending from the recording medium facing surface to the first position behind and the recording medium A first main magnetic pole layer portion including a constant width portion having a constant width that defines a recording track width of the first track, and extending backward from a second position that is recessed from the first position. And a magnetic pole layer including a second main magnetic pole layer portion separated from the main magnetic pole layer portion and having a width larger than a constant width of the first main magnetic pole layer portion.

  In the thin film magnetic head according to the present invention, the first main magnetic pole layer portion including a constant width portion extending from the recording medium facing surface to the first rear position and having a constant width defining the recording track width of the recording medium. And being separated from the first main magnetic pole layer portion by extending rearward from the second position that is retreated from the first position and larger than a certain width of the first main magnetic pole layer portion. The main magnetic pole layer of the magnetic pole layer is configured to include a second main magnetic pole layer portion having a width. In this case, for example, if the first main magnetic pole layer portion is configured such that the width of the first main magnetic pole layer portion is equal to or larger than the length of the first main magnetic pole layer portion, Based on the shape magnetic anisotropy of the main magnetic pole layer portion, the magnetic domain structure of the first main magnetic pole layer portion is determined so that the magnetization component in the direction intersecting the magnetic flux emission direction during recording is dominant. . Thereby, the magnetic domain structure of the main magnetic pole layer is optimized so that unnecessary magnetic flux is less likely to leak during non-recording.

  A magnetic recording apparatus according to the present invention includes a recording medium and a thin film magnetic head that applies magnetic processing to the recording medium, and the thin film magnetic head moves in the direction of travel of the medium and a thin film coil that generates magnetic flux. A main magnetic pole layer that extends rearward from a recording medium facing surface facing the recording medium and generates a magnetic field for magnetizing the recording medium in a direction perpendicular to the surface thereof by releasing magnetic flux generated in the thin film coil A first main magnetic pole layer portion including a constant width portion extending from the recording medium facing surface to a first rear position and having a constant width defining a recording track width of the recording medium. And separated from the first main magnetic pole layer portion by extending rearward from the second position that is recessed from the first position and larger than a certain width of the first main magnetic pole layer portion. Those comprising a pole layer and a second main pole layer portion having a width.

  In the magnetic recording apparatus according to the present invention, since the above-described thin film magnetic head is mounted, in the thin film magnetic head, the magnetic domain structure of the main magnetic pole layer is optimized so that unnecessary magnetic flux is difficult to leak during non-recording. Is done.

  In particular, in the thin film magnetic head according to the present invention, the first main magnetic pole layer portion is further connected to the rear of the constant width portion and gradually increases in width from the constant width of the constant width portion to a width larger than the constant width. It is preferable to include a widened portion that expands. In this case, the first main magnetic pole layer portion may further include a wide portion connected to the rear of the widened portion and having a constant width equal to or larger than the maximum width of the widened portion. The width of the wide portion of the first main magnetic pole layer portion is preferably equal to or smaller than the width of the second main magnetic pole layer portion.

  In the thin film magnetic head according to the present invention, the width of the second main magnetic pole layer portion is preferably equal to or greater than the length of the second main magnetic pole layer portion. In this case, the second main magnetic pole layer portion may have a continuous structure continuously extending backward from the second position, or backward from the second position. You may have the intermittent structure extended intermittently.

  In the thin film magnetic head according to the present invention, the pole layer further extends rearward from the third position between the recording medium facing surface and the first position via the second position. And an auxiliary magnetic pole layer connected by being laminated on the main magnetic pole layer. In this case, the magnetic pole layer may have a laminated structure in which the auxiliary magnetic pole layer is disposed on the side opposite to the medium traveling direction side, and the main magnetic pole layer is disposed on the medium traveling direction side. The auxiliary magnetic pole layer may be disposed on the traveling direction side, and the main magnetic pole layer may be disposed on the side opposite to the medium traveling direction side.

  Further, in the thin film magnetic head according to the present invention, the magnetic pole layer is disposed on the medium traveling direction side of the pole layer, and extends backward from the recording medium facing surface, so that the gap layer is provided on the side close to the recording medium facing surface. A magnetic shielding layer separated from the pole layer and connected to the pole layer through a back gap on the far side may be provided.

  According to the thin film magnetic head of the present invention, the main magnetic pole layer of the magnetic pole layer extends from the recording medium facing surface to the first rear position and has a constant width that defines the recording track width of the recording medium. A first main magnetic pole layer portion including a constant width portion and a first main magnetic pole layer portion separated from the first main magnetic pole layer portion by extending rearward from a second position that is recessed from the first position and For example, the width of the first main magnetic pole layer portion is the second main magnetic pole layer portion having a width larger than a certain width of the first main magnetic pole layer portion. If the first main magnetic pole layer portion is configured to be longer than the length of one main magnetic pole layer portion, the magnetic domain structure of the main magnetic pole layer is appropriate so that unnecessary magnetic flux is less likely to leak during non-recording. Information is deleted unintentionally when not recording It is possible to suppress the door.

  According to the magnetic recording apparatus according to the present invention, based on the structural features in which the thin film magnetic head described above is mounted, the main magnetic pole layer has a structure that prevents the unnecessary magnetic flux from leaking when the thin film magnetic head is not recorded. Since the magnetic domain structure is optimized, it is possible to mount a thin film magnetic head in which the magnetic domain structure of the main magnetic pole layer is optimized, and to prevent information from being erased unintentionally during non-recording.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, the configuration of a thin film magnetic head according to an embodiment of the invention will be described with reference to FIGS. 1 and 2 show the configuration of the thin film magnetic head. FIG. 1 shows the overall cross-sectional configuration, and FIG. 1A shows a cross-sectional configuration parallel to the air bearing surface (cross-sectional configuration along the XZ plane), and FIG. 1B shows a cross-sectional configuration perpendicular to the air bearing surface (cross-sectional configuration along the YZ plane). Is shown. An upward arrow M shown in FIG. 1 indicates a direction (medium traveling direction) in which a recording medium (not shown) moves relative to the thin film magnetic head.

  In the following description, the dimension in the X-axis direction shown in FIGS. 1 and 2 is expressed as “width”, the dimension in the Y-axis direction as “length”, and the dimension in the Z-axis direction as “thickness”. Further, the side near the air bearing surface in the Y-axis direction is referred to as “front”, and the opposite side is referred to as “rear”. These notation contents are the same also in FIG.

This thin film magnetic head is mounted on a magnetic recording apparatus such as a hard disk drive in order to perform magnetic processing on a recording medium such as a hard disk that moves in the medium traveling direction M. Specifically, the thin film magnetic head is, for example, a composite head capable of performing both recording processing and reproducing processing as magnetic processing. For example, as shown in FIG. 1, for example, AlTiC (Al ₂ O _3. On a substrate 1 made of a ceramic material such as TiC), an insulating layer 2 made of a nonmagnetic insulating material such as aluminum oxide (Al ₂ O ₃ ; hereinafter simply referred to as “alumina”), and magnetic A reproducing head unit 100A that performs a reproducing process using a magneto-resistive effect (MR), a separation layer 7 made of a nonmagnetic insulating material such as alumina, and a perpendicular recording method recording process. A laminated structure in which a shield type recording head unit 100B to be executed and an overcoat layer 17 made of a nonmagnetic insulating material such as alumina are laminated in this order. It is.

  The reproducing head unit 100A has, for example, a stacked structure in which a lower read shield layer 3, a shield gap film 4, and an upper read shield layer 5 are stacked in this order. An MR element 6 as a reproducing element is embedded in the shield gap film 4 so that one end face is exposed on a recording medium facing surface (air bearing surface) 40 facing the recording medium.

  The lower read shield layer 3 and the upper read shield layer 5 both magnetically isolate the MR element 6 from the periphery, and extend rearward from the air bearing surface 40. The lower lead shield layer 3 is made of a magnetic material such as a nickel iron alloy (NiFe (for example, Ni: 80 wt%, Fe: 20 wt%); hereinafter simply referred to as “Permalloy (trade name)”). The thickness is about 1.0 μm to 2.0 μm. The upper lead shield layer 5 includes, for example, an upper lead shield layer portion 5A made of a magnetic material such as permalloy, a nonmagnetic layer 5B made of a nonmagnetic material such as ruthenium (Ru) or alumina, and permalloy. The upper read shield layer portion 5C made of a magnetic material has a laminated structure (three-layer structure) laminated in this order. The upper read shield layer 5 does not necessarily have a laminated structure, and may have a single layer structure.

  The shield gap film 4 electrically isolates the MR element 6 from the periphery, and is made of a nonmagnetic insulating material such as alumina.

  The MR element 6 performs magnetic processing (reproduction processing) using, for example, a giant magnetoresistive effect (GMR) or a tunneling magnetoresistive effect (TMR). It is.

  The recording head unit 100B is covered with, for example, a magnetic pole layer 20 whose periphery is embedded by insulating layers 9 and 11, a gap layer 12 provided with an opening for magnetic connection (back gap 12BG), and an insulating layer 15. The thin film coil 14 and the write shield layer 30 have a laminated structure in which they are laminated in this order. In FIG. 2, only the thin film coil 14, the magnetic pole layer 20, and the write shield layer 30 of the recording head unit 100 </ b> B are extracted and shown as main parts of the thin film magnetic head.

  The magnetic pole layer 20 stores a magnetic flux for recording generated in the thin film coil 14 and executes a magnetic process (recording process) by releasing the magnetic flux toward a recording medium. As a recording process of the perpendicular recording system, a magnetic field (vertical magnetic field) for magnetizing a recording medium in a direction perpendicular to the surface thereof is generated by releasing a recording magnetic flux. The pole layer 20 is disposed on the leading side with respect to the thin film coil 14, extends rearward from the air bearing surface 40, and specifically corresponds to the back gap 12 BG provided in the gap layer 12. Extends to position. The “leading side” refers to the flow inflow side (the medium advancing direction M side) when the moving state of the recording medium moving in the medium advancing direction M shown in FIG. The opposite side), here the lower side in the thickness direction (Z-axis direction). On the other hand, the flow outflow side (medium traveling direction M side) is referred to as “trailing side”, and here refers to the upper side in the thickness direction.

  For example, as shown in FIG. 1, the magnetic pole layer 20 is formed by laminating an auxiliary magnetic pole layer 8 whose periphery is embedded by an insulating layer 9 and a main magnetic pole layer 10 whose periphery is embedded by an insulating layer 11 in this order. In other words, the auxiliary magnetic pole layer 8 is disposed on the leading side, and the main magnetic pole layer 10 is disposed on the trailing side.

The auxiliary magnetic pole layer 8 functions as a main magnetic flux accommodating portion, and is connected by being laminated on the main magnetic pole layer 10. This “connection” means that the magnetic connection is magnetically conductive, and the meaning of the “connection” is the same in the following description. For example, the auxiliary magnetic pole layer 8 extends rearward from a position retracted from the air bearing surface 40, and specifically extends to a position corresponding to the back gap 12BG. It is made of a magnetic material having a high saturation magnetic flux density such as an alloy. Examples of the iron cobalt alloy include iron cobalt alloy (FeCo) and iron cobalt nickel alloy (FeCoNi). In particular, the auxiliary magnetic pole layer 8 has a relatively high magnetostriction constant λ (λ) in view of optimizing the magnetic domain structure from the viewpoint of suppressing unintentional erasure of information during non-recording. Relatively lower magnetostriction than magnetic materials such as iron cobalt nickel alloy (saturated magnetic flux density Bs = 2.3T) and iron nickel alloy (saturated magnetic flux density Bs = 2.0T) having> 10 × 10 ⁻⁶ ) It is made of a magnetic material such as permalloy (saturated magnetic flux density Bs = 1.0 T) or iron nickel cobalt alloy (saturated magnetic flux density Bs = 1.8 T) having a constant λ (λ ≦ about 10 × 10 ⁻⁶ ). Is preferred. The detailed configuration of the auxiliary magnetic pole layer 8 will be described later (see FIG. 3 described later).

  The main magnetic pole layer 10 functions as a main magnetic flux emitting portion and is connected by being stacked on the auxiliary magnetic pole layer 8. For example, the main magnetic pole layer 10 extends rearward from the air bearing surface 40 and specifically extends to a position corresponding to the back gap 12BG. It is made of a magnetic material having a high saturation magnetic flux density such as an iron-cobalt alloy. In particular, the main magnetic pole layer 10 has an exposed surface 10M exposed to the air bearing surface 40, and the exposed surface 10M is, for example, an end located on the trailing side as shown in FIG. The edge (the edge located on the upper side in FIG. 1 (A); the so-called trailing edge) is the longer opposite side (upper bottom) of the two opposite sides facing each other, and the edge located on the leading side ( It has an inverted trapezoidal shape of the left and right objects with the edge located on the lower side in FIG. 1A: a so-called leading edge as the shorter opposite side (lower base) of the two opposite sides facing each other. . The detailed configuration of the main magnetic pole layer 10 will be described later (see FIG. 3 described later).

  The insulating layer 9 electrically isolates the auxiliary magnetic pole layer 8 from the surroundings, and is made of, for example, a nonmagnetic insulating material such as alumina. The insulating layer 11 electrically isolates the main magnetic pole layer 10 from the surroundings, and is made of, for example, a nonmagnetic insulating material such as alumina as with the insulating layer 9.

  The gap layer 12 constitutes a gap for magnetically separating the pole layer 20 and the write shield layer 30. The gap layer 12 is made of, for example, a nonmagnetic insulating material such as alumina or a nonmagnetic conductive material such as ruthenium (Ru), and has a thickness of about 40.0 nm.

  The thin film coil 14 generates a magnetic flux for recording, and is made of, for example, a highly conductive material such as copper (Cu). For example, as shown in FIGS. 1 and 2, the thin-film coil 14 has a winding structure (spiral structure) wound around a back gap 12BG. In FIGS. 1 and 2, only a part of the plurality of windings constituting the thin film coil 14 is shown.

  The insulating layer 15 covers the thin film coil 14 and is electrically separated from the periphery, and is disposed on the gap layer 12 so as not to block the back gap 12BG. The insulating layer 15 is made of, for example, a nonmagnetic insulating material such as a photoresist (photosensitive resin) or spin-on-glass (SOG) that exhibits fluidity when heated. The portion in the vicinity of the edge constitutes a rounded slope so as to fall toward the edge. The position of the foremost end (edge closest to the air bearing surface 40) of the insulating layer 15 is another one of the important factors that determine the recording performance of the thin film magnetic head, the “throat height zero position TP”. The distance between the air bearing surface 40 and the throat height zero position TP is a so-called “throat height TH”. 1 and 2 show a case where, for example, the throat height zero position TP coincides with the flare point FP.

  The write shield layer 30 is a magnetic shielding layer that suppresses the spread of the magnetic flux by taking in the spread component of the magnetic flux emitted from the pole layer 20. In particular, the write shield layer 30 has a function of suppressing the spread of magnetic flux as described above, for example, when the magnetic flux is emitted from the magnetic pole layer 20 toward the recording medium (via the recording medium). The magnetic flux is recovered and re-supplied to the pole layer 20, that is, the magnetic flux is circulated between the thin film magnetic head and the recording medium. The write shield layer 30 is disposed on the trailing side of the thin film coil 14, that is, on the trailing side of the magnetic pole layer 20, and is close to the air bearing surface 40 by extending backward from the air bearing surface 40. It is separated from the pole layer 20 by the gap layer 12 on the side and connected to the pole layer 20 through the back gap 12BG on the far side.

  In particular, the write shield layer 30 includes, for example, two constituent elements configured separately from each other, that is, a TH defining layer 13 that functions as a main magnetic flux intake port, and a flow of magnetic flux captured from the TH defining layer 13. And a yoke layer 16 functioning as a path. While the TH defining layer 13 is adjacent to the gap layer 12, it is located between the air bearing surface 40 and the back gap 12 BG, specifically, between the air bearing surface 40 and the thin film coil 14. Extends to position. The TH defining layer 13 is made of, for example, a magnetic material having a high saturation magnetic flux density such as permalloy or iron-cobalt alloy. For example, as shown in FIG. 2, a rectangular planar shape having a width W5. have. The TH defining layer 13 is adjacent to the insulating layer 15 in which the thin film coil 14 is embedded. That is, the TH defining layer 13 defines the foremost end position (throat height zero position TP) of the insulating layer 15. Is responsible for defining the throat height TH. On the other hand, the yoke layer 16 extends from the air bearing surface 40 to a position corresponding to the back gap 12BG so as to cover the insulating layer 15, and is connected to the TH defining layer 13 on the front side and back on the back side. It is connected adjacent to the pole layer 20 through the gap 12BG. The yoke layer 16 is made of a magnetic material having a high saturation magnetic flux density such as permalloy or an iron-cobalt alloy, for example, like the TH defining layer 13, and as shown in FIG. Similarly to the above, it has a rectangular planar shape having a width W5.

  Next, detailed configurations of the auxiliary magnetic pole layer 8 and the main magnetic pole layer 10 will be described with reference to FIGS. FIG. 3 shows a planar configuration of the auxiliary magnetic pole layer 8 and the main magnetic pole layer 10 and corresponds to FIG.

  For example, as shown in FIG. 3, the main magnetic pole layer 10 has a substantially battledore type planar shape divided in the middle. That is, the main magnetic pole layer 10 includes, for example, a front main magnetic pole layer portion 10A (first main magnetic pole layer portion) extending from the air bearing surface 40 to a rear position P1 (first position), and a position P1. A rear main magnetic pole layer portion 10B (second main magnetic pole layer portion) separated from the front main magnetic pole layer portion 10A by extending backward from the retracted position P2 (second position). Has been. The phrase “the rear main magnetic pole layer portion 10B is separated from the front main magnetic pole layer portion 10A” means that the front main magnetic pole layer portion 10A and the rear main magnetic pole layer portion 10B are physically connected in the same layer. That is, it means that the rear main magnetic pole layer portion 10B is separated from the front main magnetic pole layer portion 10A with the space S therebetween. The distance between the front main magnetic pole layer portion 10A and the rear main magnetic pole layer portion 10B, that is, the separation distance LS defined based on the space S is about 0.5 μm to 3.0 μm. In the space S, as shown in FIG. 1, a part of the insulating layer 11 is embedded.

  The front main magnetic pole layer portion 10A is a portion that substantially emits the recording magnetic flux generated in the thin film coil 14 toward the recording medium. For example, as shown in FIG. And has a length L123 as a whole. Specifically, the front main magnetic pole layer portion 10A includes, in order from the air bearing surface 40 toward the rear, a tip portion 10A1 (constant width portion) having a constant width W1 that defines the recording track width of the recording medium, and the tip thereof. An intermediate portion 10A2 (widened portion) that is connected to the rear of the portion 10A1 and gradually increases in width from a constant width W1 of the tip portion 10A1 to a width W2 (W2> W1) larger than the constant width W1, and an intermediate portion 10A2 A rear end portion 10A3 (wide portion) connected to the rear and having a constant width W3 (W3 ≧ W2) equal to or greater than the maximum width W2 of the intermediate portion 10A2, and the front end portion 10A1, the intermediate portion 10A2, and the rear end portion 10A3 has an integrated structure. In the front main magnetic pole layer portion 10A, for example, the rear end portion 10A3 extends to the position P1, that is, the rear end portion 10A3 ends at the position P1. The width W3 of the rear end portion 10A3 is, for example, equal to or smaller than the width W4 of the rear main magnetic pole layer portion 10B described later (W3 ≦ W4). Here, for example, the width W3 of the rear end portion 10A3 is equal to both the maximum width W2 of the intermediate portion 10A2 and the width W4 of the rear main magnetic pole layer portion 10B (W3 = W2, W4), and the write shield layer. It is smaller than the width W5 of 30 (TH defining layer 13, yoke layer 16) (W3 <W5). In particular, the width (maximum width) W3 of the front main magnetic pole layer portion 10A is, for example, not less than the length L123 of the front main magnetic pole layer portion 10A (W3 ≧ L123), that is, the front main magnetic pole layer portion 10A is As a whole, it has a horizontally long planar shape (longer in the X-axis direction than in the Y-axis direction). From the position where the width of the front main magnetic pole layer portion 10A extends from the front end portion 10A1 (width W1) to the intermediate portion 10A2 (maximum width W2), that is, from the width W1 where the width of the main magnetic pole layer 10 defines the recording track width of the recording medium. The position where the expansion starts is the “flare point FP” which is one of the important factors that determine the recording performance of the thin film magnetic head.

  The rear main magnetic pole layer portion 10B is a portion that supplies the recording main magnetic flux generated in the thin film coil 14 to the front main magnetic pole layer portion 10A. For example, as shown in FIG. The portion 10A has a rectangular planar shape having a width W4 (W4> W1) larger than the constant width W1 of the tip portion 10A1 and a length L4. Here, for example, the width W4 of the rear main magnetic pole layer portion 10B is equal to the width W3 of the rear end portion 10A3 of the front main magnetic pole layer portion 10A (W4 = W3), and the write shield layer 30 (TH The width W5 of the defining layer 13 and the yoke layer 16) is smaller (W4 <W5). The width W4 of the rear main magnetic pole layer portion 10B is, for example, not less than the length L4 of the rear main magnetic pole layer portion 10B (W4 ≧ L4), that is, the rear main magnetic pole layer portion 10B is substantially horizontally long (Y-axis It has a rectangular shape that is longer in the X-axis direction than in the direction. In particular, the rear main magnetic pole layer portion 10B has, for example, a continuous structure extending continuously rearward from the position P2. The “continuous structure” means a structure extending so as not to be divided (no break) in the extending range.

  The auxiliary magnetic pole layer 8 supplies the magnetic flux for recording accommodated in the rear main magnetic pole layer portion 10B of the main magnetic pole layer 10 to the front main magnetic pole layer portion 10A. For example, as shown in FIG. 3, the auxiliary magnetic pole layer 8 is positioned backward from the air bearing surface 40, specifically, a position P <b> 3 (third position) between the air bearing surface 40 and the position P <b> 1. And extending in the rearward direction via the position P2, and having a vertically long (rectangular) shape having a width W0 (longer in the Y-axis direction than in the X-axis direction). The width W0 of the auxiliary magnetic pole layer 8 is, for example, smaller than both the width (maximum width) W3 of the front main magnetic pole layer portion 10A of the main magnetic pole layer 10 and the width W4 of the rear main magnetic pole layer portion 10B. (W0 <W3, W4). In particular, the auxiliary magnetic pole layer 8 partially overlaps the main magnetic pole layer 10 (the front main magnetic pole layer portion 10A and the rear main magnetic pole layer portion 10B) both in front of the position P1 and in the rear of the position P2. The overlapping distance LP of the portion where the auxiliary magnetic pole layer 8 and the front main magnetic pole layer portion 10A overlap each other, that is, the distance between the position P3 and the position P1 is about 0.5 μm to 2.0 μm.

  Next, the operation of the thin film magnetic head will be described with reference to FIGS.

  In this thin film magnetic head, when a current flows from an external circuit (not shown) to the thin film coil 14 in the recording head unit 100B during recording of information, a magnetic flux for recording is generated in the thin film coil 14. The magnetic flux generated at this time is accommodated in the magnetic pole layer 20 (auxiliary magnetic pole layer 8, main magnetic pole layer 10 (front main magnetic pole layer portion 10A, rear main magnetic pole layer portion 10B)), and then the main magnetic layer in the magnetic pole layer 20 is forward main. It flows toward the tip 10A1 of the pole layer portion 10A. At this time, a part of the magnetic flux flowing in the magnetic pole layer 20 from the rear main magnetic pole layer portion 10B to the front main magnetic pole layer portion 10A passes through the auxiliary magnetic pole layer 8 from the rear main magnetic pole layer portion 10B. The magnetic flux flows indirectly into the main magnetic pole layer portion 10A, and the remaining magnetic flux directly flows into the front main magnetic pole layer portion 10A through the space S from the rear main magnetic pole layer portion 10B. In addition, the magnetic flux flowing inside the pole layer 20 is concentrated at the flare point FP as the width of the pole layer 20 is reduced, so that it concentrates near the trailing edge on the exposed surface 10M of the tip portion 10A1. To do. When the magnetic flux concentrated near the trailing edge is released to the outside, a magnetic field for recording (vertical magnetic field) is generated in a direction (vertical direction) perpendicular to the surface of the recording medium. Since the recording medium is magnetized in the vertical direction, information is magnetically recorded on the recording medium. In recording information, since the spread component of the magnetic flux emitted from the tip portion 10A1 is taken into the write shield layer 30, the spread of the magnetic flux is suppressed. The magnetic flux taken into the write shield layer 30 is circulated to the pole layer 20 through the back gap 12BG.

  On the other hand, at the time of reproducing information, when a sense current flows through the MR element 6 of the reproducing head unit 100A, the resistance value of the MR element 6 changes according to a reproducing signal magnetic field based on the recording medium. Since the resistance change of the MR element 6 is detected as a change in the sense current, information recorded on the recording medium is magnetically reproduced.

  In the thin film magnetic head according to the present embodiment, the front main magnetic pole layer portion 10A includes a front end portion 10A1 that extends from the air bearing surface 40 to the rear position P1 and has a constant width W1 that defines the recording track width of the recording medium. And separated from the front main magnetic pole layer portion 10A by extending rearward from the position P2 which is retreated from the position P1, and more than the constant width W1 of the front end portion 10A1 of the front main magnetic pole layer portion 10A. Since the main magnetic pole layer 10 is configured to include the rear main magnetic pole layer portion 10B having the large width W4, it is possible to suppress unintentional erasure of information during non-recording for the following reason. .

  FIG. 4 is a view for explaining the configuration of a thin film magnetic head as a comparative example with respect to the thin film magnetic head according to the present embodiment, and corresponds to FIG. FIG. 5 is for explaining the magnetic domain structure of the main magnetic pole layer regarding the thin film magnetic head according to the present embodiment, and corresponds to FIG. FIG. 6 is for explaining the magnetic domain structure of the main magnetic pole layer in the thin film magnetic head of the comparative example, and corresponds to FIG.

  In the thin film magnetic head of this comparative example, as shown in FIG. 4, the pole layer 20 includes a main pole layer 100 instead of the main pole layer 10 (the front main pole layer portion 10A and the rear main pole layer portion 10B). Except for this point, it has the same configuration as the thin film magnetic head according to the present embodiment (see FIGS. 1 to 3). The main magnetic pole layer 100 is connected to the front end 101 having a constant width W101 (W101 = W1) in order from the air bearing surface 40 to the rear, and connected to the rear of the front end 101 and from the width W101 to the width W101. An intermediate portion 102 that gradually increases in width to a larger width W102 (W102> W101, W102 = W2, W3), and a width W103 (W103 = W102) that is connected to the rear of the intermediate portion 102 and is equal to the width W102. And includes a rear end portion 103, and the front end portion 101, the intermediate portion 102, and the rear end portion 103 have an integrated structure, that is, continuously extend rearward from the air bearing surface 40. Has a continuous structure.

  In the thin film magnetic head of the comparative example, as shown in FIG. 4, due to the structural factor of the main magnetic pole layer 100 having a continuous structure extending continuously rearward from the air bearing surface 40. Since the main magnetic pole layer 100 as a whole has a vertically long (rectangular shape longer in the Y-axis direction than the X-axis) planar shape, the magnetic domain is based on the shape magnetic anisotropy of the vertically long main magnetic pole layer 100. The structure is determined. Specifically, for example, as illustrated in FIG. 6, in the magnetic domain structure of the main magnetic pole layer 100, the occupation ratio of the magnetization component 100 </ b> Y parallel to the Y-axis direction is higher than the occupation ratio of the magnetization component 100 </ b> X parallel to the X-axis. , That is, the magnetic domain structure of the main magnetic pole layer 100 is determined so that the magnetization component 100Y in the direction parallel to the magnetic flux emission direction (Y-axis direction) during recording becomes dominant.

  In this case, a recording magnetic flux is supplied from the main magnetic pole layer 100 to a recording medium (not shown) at the time of information recording, and then recording from the main magnetic pole layer 100 to the recording medium is performed after information recording. When the supply of the magnetic flux for use is interrupted, the magnetic flux (residual magnetization) remaining in the main magnetic pole layer 100 is not recorded due to the magnetic domain structure of the main magnetic pole layer 100 where the magnetization component 100Y is dominant. Sometimes it is easy to leak to the outside as an unnecessary magnetic flux. In addition, in this case, in the magnetic domain structure of the main magnetic pole layer 100, the leakage of unnecessary magnetic flux at the tip 101, that is, the degree to which unnecessary magnetic flux leaks at the tip 101, which is the magnetic flux release portion (for example, When the leakage amount, leakage frequency, etc.) are taken into consideration, the occupation area of a specific magnetic domain that greatly affects the leakage of unnecessary magnetic flux increases, and the magnetization direction of the specific magnetic domain is the magnetization component 100X. Since it becomes easier to face the magnetization direction of the magnetization component 100Y than the magnetization direction, there is a high possibility that unnecessary magnetic flux leaks from the main magnetic pole layer 100. The “specific magnetic domain” is a magnetic domain that is located in the vicinity of the tip 101 and is magnetized in a direction close to the magnetic flux release direction among the plurality of magnetic domains in the main magnetic pole layer 100. 6 is a magnetic domain specified by shading. As a result, an unnecessary magnetic field is likely to be generated based on an unnecessary magnetic flux, so that information recorded on the recording medium is easily erased unintentionally. Therefore, in the thin film magnetic head of the comparative example, the magnetic domain structure of the main magnetic pole layer 100 is not optimized from the viewpoint of suppressing information recorded on the recording medium from being erased unintentionally due to unnecessary magnetic flux. Therefore, by optimizing the magnetic domain structure of the main magnetic pole layer 100, it is difficult to suppress unintentional erasure of information during non-recording.

  In contrast, in the thin film magnetic head according to the present embodiment, as shown in FIG. 3, the main magnetic pole layer 10 is separated from the front main magnetic pole layer portion 10A and the front main magnetic pole layer portion 10A. The structural features of the main magnetic pole layer 10 including the layer portion 10B, that is, the structure corresponding to the structure in which the main magnetic pole layer 100 shown in FIG. Based on this, the front main magnetic pole layer portion 10A, which is a substantial magnetic flux emitting portion of the main magnetic pole layer 100, has a horizontally long (rectangular shape longer in the X-axis direction than the Y-axis) planar shape, Specifically, since the width (maximum width) W3 of the front main magnetic pole layer portion 10A is not less than the length L123 of the front main magnetic pole layer portion 10A (W3 ≧ L123), the horizontally long front main magnetic pole layer portion 10A. Based on the shape magnetic anisotropy of The magnetic domain structure is determined have. Specifically, for example, as shown in FIG. 5, in the magnetic domain structure of the front main magnetic pole layer portion 10A, the magnetization component 10X parallel to the X-axis direction is more than the occupation ratio of the magnetization component 10Y parallel to the Y-axis. The magnetic domain structure of the front main magnetic pole layer portion 10A is determined so that the occupation ratio increases, that is, the magnetization component 10X in the direction intersecting the magnetic flux emission direction (Y-axis direction) during recording becomes dominant.

  In this case, the recording magnetic flux is supplied from the main magnetic pole layer 10 toward the recording medium during information recording, and then the recording magnetic flux is supplied from the main magnetic pole layer 10 to the recording medium after information recording. Is interrupted, the magnetic flux remaining in the front main magnetic pole layer portion 10A is an unnecessary magnetic flux at the time of non-recording based on the magnetic domain structure of the front main magnetic pole layer portion 10A where the magnetization component 10X is dominant. It becomes difficult to leak outside. In addition, in this case, in the magnetic domain structure of the front main magnetic pole layer portion 10A, when considering the ease of leakage of unnecessary magnetic flux at the tip 10A1, the leakage of unnecessary magnetic flux is greatly affected. The occupying area of the specific magnetic domain (the magnetic domain specified by shading in FIG. 5) is reduced, and the magnetization direction of the specific magnetic domain is more in the magnetization direction of the magnetization component 10X than the magnetization direction of the magnetization component 10Y. Since it becomes easy to face, possibility that unnecessary magnetic flux will leak from 10 A of front main magnetic pole layer parts will become low. This makes it difficult for an unnecessary magnetic field to be generated based on an unnecessary magnetic flux, so that information recorded on the recording medium is not easily erased unintentionally. Therefore, in the thin film magnetic head according to the present embodiment, the magnetic domain of the front main magnetic pole layer portion 10A is suppressed from the viewpoint of preventing the information recorded on the recording medium from being erased unintentionally due to unnecessary magnetic flux. Since the structure is optimized, by optimizing the magnetic domain structure of the main magnetic pole layer 10, unintentional erasure of information during non-recording can be suppressed.

  Here, the technical significance of the thin film magnetic head according to the present embodiment will be supplemented. That is, in the thin film magnetic head according to the present embodiment, as described above, by optimizing the magnetic domain structure of the main magnetic pole layer 10, it is possible to suppress unintentional erasure of information during non-recording. In addition, the main magnetic pole layer 10 is configured to have a separation structure including the front main magnetic pole layer portion 10A and the rear main magnetic pole layer portion 10B which are separated from each other. By being applied to the thin film magnetic head according to the embodiment, that is, the perpendicular recording type thin film magnetic head, sufficient technical significance is brought about. Specifically, in a perpendicular recording type thin film magnetic head, a soft magnetic layer (so-called backing layer) is generally used to generate a strong recording magnetic field by releasing magnetic flux in a direction perpendicular to the surface of the recording medium. ) When a recording medium having a two-layer structure with a recording layer provided thereon is used, the magnetic flux remaining in the main magnetic pole layer 10 tends to be drawn into the recording medium. Considering the fact that information tends to be erased unintentionally at the time of non-recording, it is possible to suppress unintentional erasure of information at the time of non-recording while generating a strong recording magnetic field. From the viewpoint, there is a technical significance of the thin film magnetic head according to the present embodiment.

  In addition to the above, in the present embodiment, as shown in FIG. 3, the width W4 of the rear main magnetic pole layer portion 10B is equal to or greater than the length L4 of the rear main magnetic pole layer portion 10B (W4 ≧ L4). The rear main magnetic pole layer portion 10B has a horizontally long (rectangular shape longer in the X-axis direction than the Y-axis direction) plane shape, similarly to the front main magnetic pole layer portion 10A. In this case, as shown in FIG. 5, since the magnetic domain structure is determined based on the shape magnetic anisotropy of the horizontally long rear main magnetic pole layer portion 10B, the magnetization component 10X is the same as the front main magnetic pole layer portion 10A. Is determined so that the magnetic domain structure of the rear main magnetic pole layer portion 10B becomes dominant. Therefore, unnecessary magnetic flux is hardly leaked even by the magnetic domain structure of the rear main magnetic pole layer portion 10B due to the same action as the relationship between the magnetic domain structure of the front main magnetic pole layer portion 10A and the ease of leakage of unnecessary magnetic flux. In other words, the magnetic domain structure of the rear main magnetic pole layer portion 10B is optimized from the viewpoint of suppressing unintentional erasure of information recorded on the recording medium due to unnecessary magnetic flux. In addition, it is possible to prevent the information from being erased unintentionally during non-recording.

  Further, in the present embodiment, if the auxiliary magnetic pole layer 8 is formed using a magnetic material having a relatively low magnetostriction constant λ such as permalloy, this point of view is also intended at the time of non-recording for the following reason. Information can be prevented from being erased.

  FIG. 7 is for explaining the advantages of the magnetic domain structure of the auxiliary magnetic pole layer 8 and corresponds to FIG. FIG. 8 is for explaining a problem relating to the magnetic domain structure of the auxiliary magnetic pole layer 8 and also corresponds to FIG. As for the magnetic domain structure of the magnetic film, in general, the magnetic domain structure is determined based on the shape magnetic anisotropy of the magnetic film as described above, and the induced magnetic anisotropy depends on the magnetostriction constant λ of the magnetic film. It is also known that the magnetic domain structure is determined based on the property. More specifically, when a magnetic film is formed using a magnetic material having a relatively high magnetostriction constant λ, such as an iron-nickel alloy, the shape magnetism is greater than the induced magnetic anisotropy with respect to the magnetic domain structure of the magnetic film. Since anisotropy preferentially contributes, the magnetic domain structure is determined based on the shape magnetic anisotropy of the magnetic film. On the other hand, when a magnetic film is formed using a magnetic material having a relatively low magnetostriction constant λ such as permalloy, the magnetic film is induced magnetically anisotropic because the magnetostriction constant λ of the magnetic material such as permalloy is small. It is easy to be magnetized in the magnetization direction based on the properties.

  Considering the principle of determining the magnetic domain structure of the magnetic film described above, as shown in FIG. 8, a magnetic material having a relatively high magnetostriction constant λ is used so as to have a vertically long rectangular planar shape. When the magnetic pole layer 8 is configured, the magnetic domain structure is determined based on the shape magnetic anisotropy of the vertically long auxiliary magnetic pole layer 8. Therefore, in the magnetic domain structure of the auxiliary magnetic pole layer 8, magnetization parallel to the X-axis is performed. The occupation ratio of the magnetization component 8Y parallel to the Y-axis direction is larger than the occupation ratio of the component 8X, that is, the magnetization component 8Y becomes dominant. Thus, for the same reason as the relationship between the magnetic domain structure of the main magnetic pole layer 100 and the ease of leakage of unnecessary magnetic flux, unnecessary magnetic flux is likely to leak even by the magnetic domain structure of the auxiliary magnetic pole layer 8, that is, Since the magnetic domain structure of the auxiliary magnetic pole layer 8 is not optimized from the viewpoint of suppressing unintentional erasure of information recorded on the recording medium due to unnecessary magnetic flux, this aspect is also intended for non-recording. It is difficult to prevent the information from being erased without it.

  On the other hand, as shown in FIG. 7, using a magnetic material having a relatively low magnetostriction constant λ, for example, by growing a plating film in a magnetic field, it has a vertically long rectangular planar shape. When the auxiliary magnetic pole layer 8 is formed, the magnetic domain structure is determined by being magnetized in the magnetization direction based on the induced magnetic anisotropy of the auxiliary magnetic pole layer 8. In the structure, the occupation ratio of the magnetization component 8X parallel to the X-axis direction is larger than the occupation ratio of the magnetization component 8Y parallel to the Y-axis even though it has a vertically long planar shape. 8X becomes dominant. Therefore, due to the same action as the relationship between the magnetic domain structure of the front main magnetic pole layer portion 10A and the ease of leakage of unnecessary magnetic flux, unnecessary magnetic flux is hardly leaked even by the magnetic domain structure of the auxiliary magnetic pole layer 8, That is, the magnetic domain structure of the auxiliary magnetic pole layer 8 is optimized from the viewpoint of suppressing unintentional erasure of information recorded on the recording medium due to unnecessary magnetic flux. It is possible to prevent the information from being erased unintentionally.

  In the present embodiment, since the pole layer 20 is configured to include the auxiliary pole layer 8 together with the main pole layer 10, as described above, the inside of the pole layer 20 extends from the rear main pole layer portion 10B to the front main pole layer. In the process in which the magnetic flux flows through the layer portion 10A, a part of the magnetic flux flows directly from the rear main magnetic pole layer portion 10B through the space S to the front main magnetic pole layer portion 10A, and the remaining magnetic flux flows to the rear main magnetic pole portion. By passing through the auxiliary magnetic pole layer 8 from the layer portion 10B, it flows indirectly into the front main magnetic pole layer portion 10A. In this case, the magnetic flux is transferred from the rear main magnetic pole layer portion 10B to the front main magnetic pole layer portion 10A as compared with the case where the magnetic pole layer 20 is configured so as to include only the main magnetic pole layer 10 and not the auxiliary magnetic pole layer 8. Since the amount of magnetic flux supplied to the front end portion 10A1 of the front main magnetic pole layer portion 10A increases, the strength of the recording magnetic field (vertical magnetic field) can be increased.

  In this embodiment, the structure of the front main magnetic pole layer portion 10A is shown in FIG. 3, but the structure of the front main magnetic pole layer portion 10A is not necessarily limited to the structure shown in FIG. 3, and can be freely changed. It is. FIGS. 9-12 is for demonstrating the modification regarding the structure of 10 A of front main magnetic pole layer parts, and all respond | correspond to FIG. In addition, regarding the series of front main magnetic pole layer portions 10A shown in FIGS. 9 to 12, the structure other than the features described below is the same as that shown in FIG.

  First, in the present embodiment, as shown in FIG. 3, when the width W3 of the rear end portion 10A3 of the front main magnetic pole layer portion 10A is equal to or larger than the maximum width W2 of the intermediate portion 10A2 (W3 ≧ W2). ), The width W3 of the rear end portion 10A3 is made equal to the width W2 of the intermediate portion 10A2 (W3 = W2), but is not necessarily limited to this. For example, as shown in FIG. The width W3 of the end portion 10A3 may be larger than the width W2 of the intermediate portion 10A2 (W3> W2). In FIG. 9, for example, the width W3 of the rear end portion 10A3 is kept equal to the width W4 of the rear main magnetic pole layer portion 10B (W3 = W4), and the width W2 of the intermediate portion 10A2 is smaller than the width W3 of the rear end portion 10A3. (W2 <W3) is shown. Also in this case, as shown in FIG. 10 corresponding to FIG. 5, the magnetization component 10X is dominant in the magnetic domain structure of the front main magnetic pole layer portion 10A, and therefore, the same effect as in the above embodiment can be obtained. Can do. In this case, in particular, as compared with the front main magnetic pole layer portion 10A shown in FIG. 5, a specific magnetic domain that greatly affects the leakage of unnecessary magnetic flux in the magnetic domain structure of the front main magnetic pole layer portion 10A. Since the occupied area of the magnetic domain specified by shading in FIG. 10 becomes smaller, the possibility of unnecessary magnetic flux leaking from the front main magnetic pole layer portion 10A can be extremely reduced.

  Second, in the present embodiment, as shown in FIG. 3, the width W3 of the rear end portion 10A3 of the front main magnetic pole layer portion 10A is equal to or smaller than the width W4 of the rear main magnetic pole layer portion 10B (W3). ≦ W4), the width W3 of the rear end portion 10A3 is made equal to the width W4 of the rear main magnetic pole layer portion 10B (W3 = W4). However, the present invention is not necessarily limited to this. For example, as shown in FIG. As described above, the width W3 of the rear end portion 10A3 may be smaller than the width W4 of the rear main magnetic pole layer portion 10B (W3 <W4). In FIG. 11, for example, the width W3 of the rear end portion 10A3 is made smaller than the width W4 of the rear main magnetic pole layer portion 10B as described above, and the modification described in FIG. 9 is applied to the front main magnetic pole layer portion 10A. That is, the case where the width W3 of the rear end portion 10A3 is made larger than the width W2 of the intermediate portion 10A2 (W3> W2) is shown. Even in this case, the same effect as the above embodiment can be obtained.

  Thirdly, in the present embodiment, as shown in FIG. 3, the front main magnetic pole layer portion 10A is configured to include the rear end portion 10A3 together with the front end portion 10A1 and the intermediate portion 10A2, but this is not necessarily limited thereto. For example, as shown in FIG. 12, the front main magnetic pole layer portion 10A may be configured so as to include only the front end portion 10A1 and the intermediate portion 10A2 but not the rear end portion 10A3. In this case, the intermediate portion 10A2 extends to the position P1, that is, the intermediate portion 10A2 ends at the position P1. Even in this case, the same effect as the above embodiment can be obtained.

  Further, in the present embodiment, as shown in FIG. 3, the rear main magnetic pole layer portion 10B has a continuous structure that continuously extends rearward from the position P2, but this is not necessarily limited thereto. For example, the rear main magnetic pole layer portion 10B may have an intermittent structure extending intermittently from the position P2 toward the rear. Specifically, for example, by dividing the rear main magnetic pole layer portion 10B into two in the middle, as shown in FIG. 13, the front end portion 10B1 having the width W4 and the length L41, and the width W4 and The rear main magnetic pole layer portion 10B may be configured to have a two-part structure including a rear rear end portion 10B2 having a length L42. In the rear main magnetic pole layer portion 10B, the laterally long rear main magnetic pole layer portion 10B (W4 ≧ L4) whose width W4 is equal to or longer than the length L4 is divided into two, so that the width W4 of the front end portion 10B1 becomes the front end. It is larger than the length L41 of the portion 10B1 (W4> L41), that is, the front end portion 10B1 has a horizontally long planar shape, and the width W4 of the rear end portion 10B2 is larger than the length L42 of the rear end portion 10B2. It becomes larger (W4> L42), that is, the rear end portion 10B2 also has a horizontally long planar shape. In this case, as shown in FIG. 14 corresponding to FIG. 5, the magnetic domain structure of the tip portion 10B1 is such that the magnetization component 10X is dominant based on the shape magnetic anisotropy of the horizontally long tip portion 10B1. Similarly, based on the shape magnetic anisotropy of the horizontally long rear end portion 10B2, the magnetic domain structure of the rear end portion 10B2 is determined so that the magnetic field component 10X becomes dominant. In addition, in this case, the aspect ratio (width / length) is larger in both the front end portion 10B1 and the rear end portion 10B2 as compared with the rear main magnetic pole layer portion 10B shown in FIG. Since the planar shapes of both the portion 10B1 and the rear end portion 10B2 are further elongated, the occupation ratio of the magnetization component 10X in the magnetic domain structure is further increased. Therefore, the magnetic domain structure of the auxiliary magnetic pole layer 8 can be made more appropriate from the viewpoint of suppressing information recorded on the recording medium from being erased unintentionally due to unnecessary magnetic flux. The other features of the rear main magnetic pole layer portion 10B shown in FIGS. 13 and 14 are the same as those shown in FIGS. 3 and 5, respectively.

  Before explaining the confirmation, FIG. 13 illustrates the case where the rear main magnetic pole layer portion 10B is divided into two, that is, the number of divisions of the rear main magnetic pole layer portion 10B is set to two. The number of divisions of the rear main magnetic pole layer portion 10B can be freely changed within a range of two or more.

  In the present embodiment, as shown in FIG. 1, the magnetic pole layer 20 is formed so as to have a laminated structure in which the auxiliary magnetic pole layer 8 is disposed on the leading side and the main magnetic pole layer 10 is disposed on the trailing side. However, the present invention is not necessarily limited to this. For example, as shown in FIG. 15, the auxiliary magnetic pole layer 8 is arranged on the trailing side by reversing the positional relationship between the auxiliary magnetic pole layer 8 and the main magnetic pole layer 10. The magnetic pole layer 20 may be configured to have a laminated structure in which the main magnetic pole layer 10 is disposed on the leading side. Here, for example, when the position of the auxiliary magnetic pole layer 8 is changed without changing the position of the main magnetic pole layer 10, the portion where the auxiliary magnetic pole layer 8 is arranged in FIG. In addition, the extending range of the gap layer 12 is narrowed so as to ensure the location of the auxiliary magnetic pole layer 8. In this case, in particular, the insulating layer 18 embedded around the auxiliary magnetic pole layer 8 and the TH defining layer 13 and planarized together with the auxiliary magnetic pole layer 8 and the TH defining layer 13, and the insulating layer 18 and the auxiliary magnetic pole are provided. And the insulating layer 19 disposed on the flat surface constituted by the layer 8, and the position of the foremost end of the insulating layer 15 covering the thin film coil 14 is the position of the foremost end of the insulating layer 18. Is more retreating. The insulating layer 18 electrically isolates the auxiliary magnetic pole layer 8 and the TH defining layer 13 from the surroundings, and particularly defines the throat height zero position TP, and is made of, for example, a nonmagnetic insulating material such as alumina. Has been. The insulating layer 19 electrically separates between the auxiliary magnetic pole layer 8 and the thin film coil 14 and constitutes a back gap 19BG corresponding to the back gap 12BG. The nonmagnetic insulating material is used. Even in this case, the same effect as the above embodiment can be obtained. The other features of the thin film magnetic head shown in FIG. 15 are the same as those shown in FIG.

  In the present embodiment, the pole layer 20 is configured to include the auxiliary pole layer 8 together with the main pole layer 10 as shown in FIG. 1, but the present invention is not limited to this. For example, FIG. As shown in FIG. 5, the pole layer 20 may be configured to include only the main pole layer 10 and not the auxiliary pole layer 8. In this case, since the magnetic pole layer 20 is configured not to include the auxiliary magnetic pole layer 8, the insulating layer 9 embedded around the auxiliary magnetic pole layer 8 is omitted, and the separation layer 7 and the main magnetic layer 20 are omitted. The pole layer 10 and the insulating layer 11 are adjacent to each other. In particular, when the magnetic pole layer 20 is configured to include only the main magnetic pole layer 10, the above embodiment has been described in order to facilitate the flow of magnetic flux from the rear main magnetic pole layer portion 10 </ b> B to the front main magnetic pole layer portion 10 </ b> A. It is preferable to make the separation distance LS (= about 0.5 μm to 3.0 μm) smaller than the case (see FIG. 3), that is, the rear main magnetic pole layer portion 10B is closer to the front main magnetic pole layer portion 10A. The separation distance LS is preferably about 0.5 μm or less. Even in this case, the same effect as the above embodiment can be obtained. The other features of the thin film magnetic head shown in FIG. 16 are the same as those shown in FIG.

  This is the end of the description of the thin film magnetic head according to the embodiment of the invention.

  Next, with reference to FIGS. 17 and 18, the configuration of a magnetic recording apparatus equipped with the thin film magnetic head of the present invention will be described. FIG. 17 illustrates a perspective configuration of the magnetic recording apparatus, and FIG. 18 illustrates an enlarged perspective configuration of a main part of the magnetic recording apparatus. This magnetic recording apparatus is equipped with the thin film magnetic head described in the above embodiment, and is, for example, a hard disk drive.

  For example, as shown in FIG. 17, this magnetic recording apparatus includes a plurality of magnetic disks (for example, hard disks) 201 as recording media on which information is magnetically recorded, and each magnetic disk 201. And a plurality of suspensions 203 that support the magnetic head slider 202 at one end, and a plurality of arms 204 that support the other end of the suspension 203. The magnetic disk 201 is rotatable around a spindle motor 205 fixed to the housing 200. The arm 204 is connected to a drive unit 206 serving as a power source, and can turn around a fixed shaft 207 fixed to the housing 200 via a bearing 208. The drive unit 206 is configured to include a drive source such as a voice coil motor, for example. This magnetic recording apparatus is, for example, a model in which a plurality of arms 204 can pivot integrally around a fixed shaft 207. In FIG. 17, the housing 200 is partially cut away to make it easy to see the internal structure of the magnetic recording apparatus.

  As shown in FIG. 18, the magnetic head slider 202 is a thin film that performs both recording processing and reproducing processing on one surface of a base body 211 having a substantially rectangular parallelepiped structure made of a nonmagnetic insulating material such as Altic. The magnetic head 212 is attached. The base body 211 has, for example, one surface (air bearing surface 220) provided with a concavo-convex structure for reducing the air resistance generated when the arm 204 turns, and another surface orthogonal to the air bearing surface 220. A thin film magnetic head 212 is attached to the right front surface in FIG. The thin film magnetic head 212 has the configuration described in the above embodiment (see FIGS. 1 to 3). When the magnetic disk 201 rotates during recording or reproduction of information, the magnetic head slider 202 generates air between the recording surface (the surface facing the magnetic head slider 202) of the magnetic disk 201 and the air bearing surface 220. By using the flow, it floats from the recording surface of the magnetic disk 201. In FIG. 18, in order to make the structure on the air bearing surface 220 side of the magnetic head slider 202 easier to see, the state shown in FIG.

  In this magnetic recording apparatus, the magnetic head slider 202 moves to a predetermined area (recording area) of the magnetic disk 201 by turning the arm 204 at the time of recording or reproducing information. When the thin film magnetic head 212 is energized while facing the magnetic disk 201, the thin film magnetic head 212 operates based on the operating principle described in the above embodiment, so that the thin film magnetic head 212 becomes magnetic disk. 201 is subjected to recording processing or reproduction processing.

  In this magnetic recording apparatus, since the thin film magnetic head 212 described in the above embodiment is mounted, the front main magnetic pole layer portion 10A is less likely to leak unnecessary magnetic flux in the thin film magnetic head 212 when not recording. The magnetic domain structure is optimized. Therefore, it is possible to mount the thin film magnetic head 212 with the magnetic domain structure of the main magnetic pole layer 10 optimized, and to prevent information from being erased unintentionally during non-recording.

  Since the configuration, operation, action, effect, and modification other than those described above regarding the thin film magnetic head 212 mounted on this magnetic recording apparatus are the same as those in the above embodiment, description thereof is omitted.

  Next, examples relating to the present invention will be described.

  By mounting the series of thin film magnetic heads described in the above embodiment on a magnetic recording apparatus (see FIGS. 17 and 18), recording performance was examined while performing recording processing using the magnetic recording apparatus. The following series of results were obtained.

  First, when a thin film magnetic head (hereinafter simply referred to as “thin film magnetic head of the present invention”) having a main magnetic pole layer having the structural features shown in FIG. The result shown in FIG. 19 was obtained. FIG. 19 shows the recording width dependency with respect to the deterioration state of the recording signal. The “horizontal axis” shows the recording width W (μm), that is, the recording track width on the recording medium, and the “vertical axis” shows the signal intensity ratio S (−) is shown. When investigating the degradation status of this recording signal, the thin film magnetic head is used to perform normal recording processing by energizing the thin film coil, and the thin film magnetic head is subsequently used without energizing the thin film coil. After the recording medium was traced in the same manner as in normal recording, the recording medium was normally reproduced using a thin film magnetic head. At this time, by examining the intensity S1 of the recording signal before tracing and the intensity S2 of the reproduction signal after tracing, the signal intensity ratio S (= S2 / S1) was calculated based on those intensities S1 and S2. That is, the signal intensity ratio S is an index representing the attenuation state of the recording signal before and after the trace, that is, the ease of erasing unintended information when not recording. The number N of measurement data of the data shown in FIG. 19 is N = 40.

  Incidentally, when examining the deterioration state of the recording signal concerning the thin film magnetic head of the present invention, in order to compare and evaluate the deterioration state of the recording signal, a comparison provided with the main magnetic pole layer having the structural features shown in FIG. The deterioration state of the recording signal concerning the thin film magnetic head of the example was examined in the same manner, and the result is shown in FIG. The number N of measurement data of the data shown in FIG. 20 is N = 50.

  As can be seen from the results shown in FIG. 20, in the thin film magnetic head of the comparative example, the signal intensity ratio S is distributed over a wide range as the recording width W changes. It was widely distributed over the range of 0.03 to 1.0. This result shows that in the thin film magnetic head of the comparative example, the magnetic domain structure is not optimized due to the shape magnetic anisotropy of the main magnetic pole layer, so that information is easily erased unintentionally during non-recording. Yes. On the other hand, as can be seen from the results shown in FIG. 19, in the thin film magnetic head of the present invention, the signal intensity ratio S is distributed over a narrow range as the recording width W changes. The intensity ratio S was distributed over a range of about 0.94 to 1.0. In particular, assuming that the lower limit of the allowable signal intensity ratio S at the product level of the thin film magnetic head is 0.85, the deterioration state of the recording signal is all within the allowable range in the thin film magnetic head of the present invention. This result shows that in the thin-film magnetic head of the present invention, the magnetic domain structure is optimized based on the shape magnetic anisotropy of the main magnetic pole layer, so that information is hardly erased during non-recording. From this, it was confirmed that in the thin film magnetic head of the present invention, it is possible to suppress unintentional erasure of information during non-recording by optimizing the magnetic domain structure of the main magnetic pole layer. It was done.

  Subsequently, a thin film magnetic head (hereinafter simply referred to as “thin film magnetic head of the present invention”) provided with a main magnetic pole layer having the structural features shown as modified examples in FIGS. 9, 11 and 12 is used. When the performance yield was examined, the results shown in Table 1 were obtained. Table 1 shows the performance yield of the thin film magnetic head. When investigating the performance yield of this thin film magnetic head, using a thin film magnetic head having a series of main magnetic pole layers, the signal intensity ratio is calculated in the same manner as when the deterioration state of the recording signal is examined, For each thin film magnetic head, the number ratio satisfying an acceptable signal intensity ratio (= 0.85 or more) at the product level is examined, and the number ratio is determined as “performance yield (%)” in the “present invention”. It is shown in Table 1. That is, “performance yield” is an index represented by performance yield (%) = (number of thin film magnetic heads satisfying an acceptable signal intensity ratio at the product level / total number of thin film magnetic heads) × 100. It is. Of the “present invention” shown in Table 1, “S1” indicates the case where the main magnetic pole layer shown in FIG. 9 is used, “S2” indicates the case where the main magnetic pole layer shown in FIG. 11 is used, “S3” indicates a case where the main magnetic pole layer shown in FIG. 12 is used. When investigating the performance yield of the thin film magnetic head of the present invention, a comparative thin film magnetic device having a main magnetic pole layer having the structural features shown in FIG. 4 is used for comparative evaluation of the performance yield. The performance yield concerning the head was examined in the same manner, and the result is also shown in Table 1 as “Performance yield (%)” of “Comparative Example”.

  As can be seen from the results shown in Table 1, the manufacturing yield of the thin film magnetic head of the comparative example was 45%. However, in the thin film magnetic head of the present invention, S1 (when the main magnetic pole layer shown in FIG. 9 was used) ), S2 (when the main magnetic pole layer shown in FIG. 11 is used) and S3 (when the main magnetic pole layer shown in FIG. 12 is used), the manufacturing yield is 100%. It should be noted that the thin film magnetic head of the present invention has a performance yield of 100 even when the main magnetic pole layer shown in FIG. 3 is used as described above with reference to FIG. %Met. Therefore, in the thin film magnetic head of the present invention, it is possible to ensure an acceptable performance yield at the product level from the viewpoint of suppressing unintentional erasure of information when not recording. Was confirmed.

  The present invention has been described with reference to the embodiment and examples. However, the present invention is not limited to the above embodiment and example, and various modifications can be made. Specifically, for example, in the above-described embodiments and examples, the case where the present invention is applied to a composite thin film magnetic head has been described. However, the present invention is not necessarily limited to this. For example, inductive magnetism for writing is used. The present invention is also applicable to a recording-only thin film magnetic head having a conversion element and a thin film magnetic head having an inductive magnetic conversion element for both recording and reproduction. Of course, the present invention can also be applied to a thin film magnetic head having a structure in which the stacking order of the writing element and the reading element is reversed.

  The thin film magnetic head according to the present invention can be applied to a magnetic recording apparatus such as a hard disk drive that magnetically records information on a hard disk.

1 is a cross-sectional view illustrating a cross-sectional configuration of a thin film magnetic head according to an embodiment of the invention. FIG. 2 is a plan view illustrating a planar configuration of a main part of the thin film magnetic head illustrated in FIG. 1. FIG. 2 is a plan view showing a planar configuration of an auxiliary magnetic pole layer and a main magnetic pole layer in the thin film magnetic head shown in FIG. 1. It is a top view showing the plane structure of the main magnetic pole layer of the thin film magnetic head of the comparative example with respect to the thin film magnetic head which concerns on one embodiment of this invention. It is a top view for demonstrating the advantage regarding the magnetic domain structure of the main magnetic pole layer among the thin film magnetic heads concerning one embodiment of the present invention. It is a top view for demonstrating the problem regarding the magnetic domain structure of the main magnetic pole layer among the thin film magnetic heads of a comparative example. It is a top view for demonstrating the advantage regarding the magnetic domain structure of an auxiliary | assistant magnetic pole layer. It is a top view for demonstrating the problem regarding the magnetic domain structure of an auxiliary | assistant magnetic pole layer. It is a top view showing the 1st modification regarding the structure of a front main magnetic pole layer part. FIG. 10 is a plan view for explaining the magnetic domain structure of the front main magnetic pole layer portion shown in FIG. 9. It is a top view showing the 2nd modification regarding the structure of a front main magnetic pole layer part. It is a top view showing the 3rd modification regarding the structure of a front main magnetic pole layer part. It is a top view showing the modification regarding the structure of a back main magnetic pole layer part. It is a top view for demonstrating the magnetic domain structure of the back main magnetic pole layer part shown in FIG. It is sectional drawing showing the modification regarding the structure of the thin film magnetic head which concerns on one embodiment of this invention. It is sectional drawing showing the other modification regarding the structure of the thin film magnetic head which concerns on one embodiment of this invention. 1 is a perspective view showing a perspective configuration of a magnetic recording apparatus equipped with a thin film magnetic head of the present invention. FIG. 18 is an enlarged perspective view illustrating a perspective configuration of a main part of the magnetic recording apparatus illustrated in FIG. 17. It is a figure showing the recording width dependence regarding the deterioration condition of the recording signal regarding the thin film magnetic head of this invention. It is a figure showing the recording width dependence regarding the deterioration condition of the recording signal regarding the thin film magnetic head of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2, 9, 11, 15, 18, 19 ... Insulating layer, 3 ... Lower lead shield layer, 4 ... Shield gap film, 5 ... Upper lead shield layer, 5A, 5C ... Upper lead shield layer part, 5B ... nonmagnetic layer, 6 ... MR element, 7 ... separation layer, 8 ... auxiliary magnetic pole layer, 8X, 8Y, 10X, 10Y ... magnetizing component, 10 ... main magnetic pole layer, 10A ... front main magnetic pole layer portion, 10A1, 10B1 ... Front end portion, 10A2 ... intermediate portion, 10A3, 10B2 ... rear end portion, 10B ... rear main magnetic pole layer portion, 10M ... exposed surface, 12 ... gap layer, 12BG, 19BG ... back gap, 13 ... TH defining layer, 14 ... thin film Coil, 16 ... Yoke layer, 17 ... Overcoat layer, 20 ... Pole layer, 30 ... Write shield layer, 40,220 ... Air bearing surface, 100A ... Reading head portion, 100B ... Recording head portion, DESCRIPTION OF SYMBOLS 00 ... Housing, 201 ... Magnetic disk, 202 ... Magnetic head slider, 203 ... Suspension, 204 ... Arm, 205 ... Spindle motor, 206 ... Drive part, 207 ... Fixed shaft, 208 ... Bearing, 211 ... Base | substrate, 212 ... Thin film Magnetic head, FP ... Flare point, L4, L123 ... Length, LP ... Overlap distance, LS ... Separation distance, M ... Media traveling direction, P1-P3 ... Position, S ... Space, TH ... Throat height, TP ... Throat height Zero position, W0-W5 ... Width.

Claims (13)

A thin-film coil that generates magnetic flux;
In order to magnetize the recording medium in a direction orthogonal to the surface thereof by extending backward from the recording medium facing surface facing the recording medium moving in the medium traveling direction and releasing the magnetic flux generated in the thin film coil The main magnetic pole layer that generates a magnetic field of a predetermined width, the main magnetic pole layer extending from the recording medium facing surface to the first position behind and having a constant width that defines a recording track width of the recording medium A first main magnetic pole layer portion including the first main magnetic pole layer portion and a second main position that is rearward from the first position and extending rearward from the first main magnetic pole layer portion; And a second main magnetic pole layer portion having a width larger than the predetermined width of the main magnetic pole layer portion. 1. A thin film magnetic head comprising: The thin film magnetic head according to claim 1, wherein the width of the first main magnetic pole layer portion is equal to or greater than the length of the first main magnetic pole layer portion. The first main magnetic pole layer portion further includes a widened portion connected to the rear of the constant width portion and gradually widening from a constant width of the constant width portion to a width larger than the constant width. The thin film magnetic head according to claim 1, wherein: The first main magnetic pole layer portion further includes a wide portion connected to the rear of the widened portion and having a constant width equal to or greater than a maximum width of the widened portion. Thin film magnetic head. The thin film magnetic head according to claim 4, wherein a width of the wide portion of the first main magnetic pole layer portion is equal to or smaller than a width of the second main magnetic pole layer portion. 6. The thin film magnetic according to claim 1, wherein a width of the second main magnetic pole layer portion is equal to or greater than a length of the second main magnetic pole layer portion. head. The second main magnetic pole layer portion has a continuous structure that continuously extends rearward from the second position. 7. The thin film magnetic head described in 1. The said 2nd main magnetic pole layer part has the intermittent structure extended intermittently toward the back from the said 2nd position. Any one of Claim 1 thru | or 6 characterized by the above-mentioned. The thin film magnetic head described in 1. The magnetic pole layer further extends rearward from the third position between the recording medium facing surface and the first position via the second position and is stacked on the main magnetic pole layer. The thin-film magnetic head according to claim 1, further comprising: an auxiliary magnetic pole layer coupled by being performed. The magnetic pole layer has a laminated structure in which the auxiliary magnetic pole layer is disposed on a side opposite to the medium traveling direction side, and the main magnetic pole layer is disposed on the medium traveling direction side. Item 10. The thin film magnetic head according to Item 9. The magnetic pole layer has a laminated structure in which the auxiliary magnetic pole layer is disposed on the medium traveling direction side, and the main magnetic pole layer is disposed on the opposite side to the medium traveling direction side. Item 10. The thin film magnetic head according to Item 9. Further, the magnetic pole layer is disposed on the medium traveling direction side of the magnetic pole layer, and extends rearward from the recording medium facing surface, so that it is separated from the magnetic pole layer by the gap layer on the side close to the recording medium facing surface and far from the magnetic recording medium. The thin film magnetic head according to claim 1, further comprising: a magnetic shielding layer connected to the magnetic pole layer through a back gap on the side. A recording medium, and a thin film magnetic head for magnetically processing the recording medium,
The thin film magnetic head
A thin-film coil that generates magnetic flux;
In order to magnetize the recording medium in a direction orthogonal to the surface thereof by extending backward from the recording medium facing surface facing the recording medium moving in the medium traveling direction and releasing the magnetic flux generated in the thin film coil The main magnetic pole layer that generates a magnetic field of a predetermined width, the main magnetic pole layer extending from the recording medium facing surface to the first position behind and having a constant width that defines a recording track width of the recording medium A first main magnetic pole layer portion including the first main magnetic pole layer portion and a second main position that is rearward from the first position and extending rearward from the first main magnetic pole layer portion; A magnetic pole layer including a second main magnetic pole layer portion having a width larger than the predetermined width of the first main magnetic pole layer portion.

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