JP2006277905A - Magnetic head for vertical recording and magnetic storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head for vertical recording having favorable magnetic field strength distribution of a recording magnetic field, suppressing side erasure and allowing high density recording, and a storage device. <P>SOLUTION: For the recording element 20 of the magnetic head 10 for vertical recording, a main magnetic pole 21 and a sub magnetic pole distal end part 30 through a nonmagnetic part 22 are provided facing each other on a surface 11 facing a medium. In the sub magnetic pole distal end part 30, a first low Bs part 31 and a high Bs part 32 are arranged in the order from the side of the main magnetic pole 21, and a second low Bs part 33 is arranged in the track width direction and trailing side of the high Bs part 32. The high Bs part 32 is composed of a soft magnetic ferromagnetic material whose saturation magnetic flux density is higher than the first low Bs part 31 and the second low Bs part 33, and the width in the track width direction of the high Bs part 32 is set to be almost equal to or more than the width on the trailing side of the main magnetic pole 21 and double or less than that. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic head for perpendicular recording and a magnetic storage device.

  Conventionally, the mainstream of magnetic storage devices is an in-plane recording method in which magnetization is formed in a recording layer of a magnetic recording medium in parallel to the substrate surface. The in-plane recording method has a problem of so-called thermal stability of recorded magnetization in which the magnitude of recorded magnetization decreases with time as the recording density is improved. On the other hand, a perpendicular recording method has been proposed in which magnetization is formed in a recording layer of a magnetic recording medium in a direction perpendicular to the substrate surface. Since the perpendicular recording method has higher thermal stability of recorded magnetization than the in-plane recording method, it is expected to achieve a higher recording density than the in-plane recording method.

As shown in FIG. 1, the conventional perpendicular recording magnetic head has a reproducing element 101 including a magnetoresistive (MR) film 104 and shield portions 102 and 103 sandwiching the magnetoresistive effect (MR) film, a main magnetic pole 106, A recording element 105 including a sub magnetic pole 107 is included. The reproducing element 101 and the recording element 105 are arranged in this order along the direction in which the magnetic recording medium moves (the direction indicated by the arrow). When recording, the perpendicular recording magnetic head applies a recording magnetic field from the main magnetic pole 106 to the recording layer of the magnetic recording medium in a direction perpendicular to the film surface. The magnetic recording medium has a soft magnetic backing layer and a recording layer on a substrate, and a recording magnetic field magnetizes the recording layer and is sucked from the sub magnetic pole 107 through the soft magnetic backing layer and further through the recording layer on the sub magnetic pole 107 side. . The magnetic pole width of the main magnetic pole 106 is formed equal to the track width of the magnetic recording medium. On the other hand, the auxiliary magnetic pole 107 is formed to extend in the track width direction so as to absorb the magnetic field as a return path of the recording magnetic field.
JP 2004-095006 A

  In the structure shown in FIG. 1, since the magnetic field attracted by the sub magnetic pole 107 spreads in the track width direction, the magnetization already recorded in the track adjacent to the recording track is affected. That is, since a magnetic field is applied to the track adjacent to the recording track every time recording is performed, a problem that the magnetization gradually decreases, that is, a problem that side erasure due to the sub magnetic pole 107 occurs.

  On the other hand, it is conceivable to reduce the magnetic field applied to the adjacent track by simply reducing the width of the sub magnetic pole 107 in the track width direction. In this case, however, the magnetic field strength sucked into the sub magnetic pole 107 in the recording track increases. . As a result, the magnetization recorded by the recording magnetic field from the main magnetic pole 106 is demagnetized by the magnetic field absorbed by the sub magnetic pole 107. In such a case, the S / N ratio is deteriorated and an error is likely to occur.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a perpendicular recording magnetic head that has a good magnetic field strength distribution of a recording magnetic field, suppresses side erasure, and enables high-density recording. It is to provide a storage device.

  According to one aspect of the present invention, a main magnetic pole that is disposed along the recording direction and applies a recording magnetic field, a sub-magnetic pole that faces the main magnetic pole and serves as a return path of the recording magnetic field, and a main magnetic pole and a sub-magnetic pole are provided. A magnetic head for perpendicular recording comprising a recording element having a magnetically connected yoke, wherein the sub magnetic pole has a sub magnetic pole tip on the side facing the main magnetic pole, and the sub magnetic pole tip is a main magnetic pole A first soft magnetic portion extending in a width direction perpendicular to the recording direction and a center line in contact with the first soft magnetic portion and extending along the recording direction of the main pole in order from the side A second soft magnetic portion disposed substantially symmetrically in the width direction, and third soft magnetic portions on both sides in the width direction of the second soft magnetic portion, and the second soft magnetic portion The portion is made of a ferromagnetic material having a saturation magnetic flux density higher than that of the first soft magnetic portion and the third soft magnetic portion. A magnetic head for perpendicular recording is provided.

  According to the present invention, the tip of the secondary magnetic pole is provided on the trailing side of the main magnetic pole, and the tip of the secondary magnetic pole is arranged from the main magnetic pole to the first soft magnetic part and the second soft magnetic part in this order. A third soft magnetic part is disposed in the track width direction and the trailing side of the second soft magnetic part. By forming the second soft magnetic portion with a predetermined width, the magnetic field strength absorbed by the sub-magnetic pole can be reduced while maintaining the steep gradient of the recording magnetic field on the trailing side of the main magnetic pole. Side erase can be suppressed. As a result, it is possible to suppress the deterioration of the S / N ratio due to the side erase and increase the recording density.

  According to another aspect of the present invention, a magnetic recording medium in which a substrate and a recording layer made of a soft magnetic backing layer and a perpendicular magnetization film are sequentially stacked on the substrate, and the magnetic head for perpendicular recording described above, A magnetic storage device is provided.

  According to the present invention, it is possible to realize a magnetic storage device capable of suppressing the deterioration of the S / N ratio due to side erasure when the perpendicular recording magnetic head records on the magnetic recording medium and increasing the recording density.

  According to the present invention, it is possible to provide a perpendicular recording magnetic head and a storage device that have a good magnetic field strength distribution of a recording magnetic field, suppress side erasure, and enable high-density recording.

  Embodiments will be described below with reference to the drawings.

(First embodiment)
FIG. 2 is a cross-sectional view of the element portion of the perpendicular recording magnetic head according to the first embodiment of the present invention. FIG. 3 is a view of the recording element of the perpendicular recording magnetic head shown in FIG. FIG. FIG. 2 also shows the magnetic recording medium. 2 and 3, the X ₁ direction trailing direction (or the trailing side), the X ₂ direction is referred to as a leading direction (or the leading side). Further, the X ₁ direction and the X ₂ direction are also referred to as a thickness direction. Direction X ₁ is a moving direction of the magnetic recording medium, that is, the recording direction in the recording operation. That is, the trailing direction (or trailing side) is the downstream direction (or downstream side) of the recording direction. The Y ₁ direction and the Y ₂ direction are referred to as the track width direction. The Z ₁ direction is referred to as a depth direction, and the Z ₂ direction is referred to as a medium facing surface direction (or medium facing surface direction).

  2 and 3, the perpendicular recording magnetic head 10 has a magnetoresistive (MR) film 17 on the surface 11 facing the magnetic recording medium 40 (hereinafter referred to as “medium facing surface”). The reproducing element 15 and the recording element 20 are included. The magnetic recording medium 40 has a recording layer 43 made of a perpendicular magnetization film and a soft magnetic backing layer 42 made of a soft magnetic film on the substrate 41 side. The perpendicular recording magnetic head 10 may be, for example, a flying type magnetic head that floats on the magnetic recording medium 40 or a contact type magnetic head that substantially contacts the magnetic recording medium 40.

  The reproducing element 15 has a configuration in which an MR film 17 is provided on the medium facing surface 11 side through a nonmagnetic portion 18 between a lower shield layer 16 and an upper shield layer 19 made of a soft magnetic material. The MR film 17 detects the direction of magnetization of the recording layer 43 as a change in electrical resistance, obtains a reproduction signal, and reproduces information recorded on the recording layer 43. The MR film 17 may be any one of a CIP (Current-In-Plane) type or CPP (Current-Perpendicular-to-Plane) type spin valve film and a TMR (Tunnel Magnetoresistance Effect) film, and is not particularly limited.

The recording element 20 is provided with a main magnetic pole 21 and a sub magnetic pole 23 via a nonmagnetic portion 22 made of an alumina film on the medium facing surface 11 side. The main magnetic pole 21 is depth direction (Z ₁ direction) connected via a yoke 25 sub magnetic pole 23 and magnetically with the lower auxiliary magnetic pole 24 on the side. Further, a recording coil 26 around which the yoke 25 is wound is provided. By passing a recording signal (recording current) through the recording coil 26, a recording magnetic field is induced in the yoke 25, and the path of the tip 21 a of the main magnetic pole 21 → the recording layer 43 → the soft magnetic backing layer 42 → the recording layer 43 → the sub magnetic pole 23. Thus, the recording magnetic field H _MP is applied from the recording element 20 to the magnetic recording medium 40, and the magnetic field H _SP is sucked from the sub magnetic pole 23. During recording, the direction of the recording magnetic field is alternately reversed along this path, so that upward and downward magnetization is formed in the recording layer 43. For convenience of explanation, it is assumed that the recording magnetic field flows out of the main magnetic pole 21 and is sucked in from the sub magnetic pole 23.

  The main magnetic pole 21 has a trapezoidal shape in which the side of the medium facing surface 11 is longer on the trailing side than on the leading side. With such a shape, the trailing-side recording magnetic field distribution applied from the main magnetic pole 21 to the recording layer 43 can be set to a preferable distribution. That is, the spread of the recording magnetic field in the track width direction is suppressed, and the track edge noise is reduced. Hereinafter, the width of the main magnetic pole 21 (main magnetic pole width) is the length of the side on the trailing side.

  The main magnetic pole 21 is made of a soft magnetic ferromagnetic material containing Fe, Ni, or Co. The ferromagnetic material of the main pole 21 is preferably as the saturation magnetic flux density Bs is higher. However, the ferromagnetic material suitable for the main magnetic pole 21 has a maximum saturation magnetic flux density Bs of 2.4 T, so that it is particularly preferable to select from ferromagnetic materials in the range of 2.0 T to 2.4 T.

Examples of the ferromagnetic material of the main magnetic pole 21 include materials containing CoFe, CoNiFe, or NiFe as a main component. Examples of the ferromagnetic material suitable for the main magnetic pole 21 include FeCo (for example, Fe ₇₀ Co ₃₀ ), FeCo alloys such as FeCoNi and FeCoAlO, FeN, FeSiN, Ni ₅₀ Fe ₅₀ , and CoZrNb.

The sub magnetic pole 23 is provided so as to protrude toward the main magnetic pole 21 on the medium facing surface 11 side. In the sub magnetic pole 23, the sub magnetic pole tip 30, the sub magnetic pole connecting portion 34, and the sub magnetic pole main portion 35 are arranged in this order from the main magnetic pole 21 side. Auxiliary pole tip 30 (the length of the Z ₁ direction from the air bearing surface 11) depth is lower than the sub pole connection 34 and auxiliary pole main portion 35. By doing so, the recording magnetic field generated from the main magnetic pole 21 is not lowered by not extremely increasing the magnetic field absorbed by the sub magnetic pole 23. By providing the auxiliary magnetic pole tip 30 close to the main magnetic pole 21 in this way, the magnetic field strength distribution of the recording magnetic field applied from the main magnetic pole 21 to the magnetic recording medium can be made a preferable distribution.

  The auxiliary magnetic pole tip 30 further includes a first low Bs portion 31 and a high Bs portion 32 arranged in this order from the main magnetic pole 21 side, and a second low Bs is provided in the track width direction and the trailing side of the high Bs portion 32. The part 33 is arranged. As will be described in detail later, the high Bs portion 32 is made of a ferromagnetic material having a saturation magnetic flux density higher than that of the first low Bs portion 31 and the second low Bs portion 33.

4A and 4B are diagrams for explaining the effects of the present invention. 4A shows the recording element viewed from the medium facing surface side of FIG. 3 in a different direction. FIG. 4B shows the center of the recording layer when a recording magnetic field is applied (FIG. 4B). FIG. 3 is a diagram showing the magnetic field strength at the center in the thickness direction of the recording layer 43 shown in FIG. 2. The magnetic field intensity indicates the magnitude of the vertical magnetic field component to the film surface of the recording layer, and a positive value a magnetic field in the Z ₂ direction in FIG. The magnetic field intensity is shown from the position facing the main magnetic pole 21 to the position facing the second low Bs portion 33 along the trailing direction, corresponding to the arrangement of the recording elements shown in FIG. Yes. As for the magnetic field strength, the magnetic field strength on the track center line (on-track position) indicated by reference sign CL is indicated by a broken line, and the magnetic field strength at a position off track TRK (off-track position) is indicated by a solid line.

In FIG. 4B, the maximum magnetic field strength at the on-track position corresponding to the main magnetic pole 21 is H _MP1 , and the maximum magnetic field strength at the off-track position is H _MP2 . The maximum magnetic field strength at the on-track position corresponding to the sub-magnetic pole tip 30 is H _SP1 , and the maximum magnetic field strength at the off-track position is H _SP2 . Further, the magnetic field intensity at which the magnetization reversal of the recording layer 43 occurs is indicated as Ha. Hereinafter, the sub magnetic pole 23 will be described in detail with reference to FIGS. 2 and 3 and FIG. 4 as appropriate.

The first low Bs portion 31 faces the main magnetic pole 21 and is provided via the nonmagnetic portion 22. The first low Bs portion 31 has a predetermined thickness and extends in the track width direction and the depth direction. The width of the first low Bs portion 31 is set wider than the width of the high Bs portion 32. By setting in this way, the strength of the magnetic field sucked into the high Bs portion 32 (H _SP1 shown in FIG. 4B) can be reduced as compared with the case where the first low Bs portion 31 is not provided. As a result, it is possible to prevent the magnetization recorded on the main magnetic pole 21 side during recording from being demagnetized by the magnetic field sucked into the sub magnetic pole 23.

  The high Bs portion 32 is provided in contact with the trailing side of the first low Bs portion 31. The high Bs portion 32 has a predetermined thickness and a predetermined width in the track width direction, and extends in the depth direction. The high Bs portion 32 is formed such that the center in the width direction of the high Bs portion 32 coincides with the track center line CL that is the center line of the main magnetic pole 21 with respect to the track width direction. By forming in this way, the magnetic field strength distribution in the track width direction can be made symmetric with respect to the track center line CL.

The width of the high Bs portion 32 is preferably set to be approximately equal to or greater than the width of the main magnetic pole 21. When the width of the high Bs portion 32 becomes narrower than the width of the main magnetic pole 21, the intensity of the magnetic field sucked into the high Bs portion 32 (H _SP1 shown in FIG. 4B) increases and the magnetization recorded by the main magnetic pole 21 is increased. The secondary magnetic pole 23 tends to demagnetize. However, the width of the high Bs portion 32 is preferably set to be not more than twice the width of the main magnetic pole 21. When the width of the high Bs portion 32 exceeds twice the width of the main magnetic pole 21, the recording magnetic field distribution of the main magnetic pole 21 spreads in the in-plane direction of the recording layer of the magnetic recording medium. In such a case, the strength of the magnetic field sucked into the sub magnetic pole 23 at the off-track position (H _SP2 shown in FIG. 4B) increases, and the degree of side erase that demagnetizes the magnetization recorded at the off-track position. To increase.

  Furthermore, according to an embodiment described later, the width of the high Bs portion 32 is more preferably equal to or greater than the width of the main magnetic pole 21 and twice or less. Further, the thickness of the high Bs portion 32 is appropriately adjusted depending on the total volume of the high Bs portion 32, but is preferably set to 50 nm to 500 nm from the viewpoint of the ease of the process and the effect depending on the magnetic field strength to be sucked.

The second low Bs portion 33 is provided in contact with the trailing side of the first low Bs portion 31 and the high Bs portion 32. The second low Bs portion 33 extends in the track width direction and the depth direction. By doing so, it is possible to reduce the magnetic field strength (H _SP1 shown in FIG. 4B) sucked into the high Bs portion 32, compared to the case of using a nonmagnetic material without providing the second low Bs portion 33. The second low Bs portion 33 is also provided on the trailing side of the high Bs portion 32, but is not essential.

  The distance between the sub magnetic pole tip 30 and the main magnetic pole 21, that is, the distance between the leading side of the first low Bs portion and the trailing side of the main magnetic pole 21, is preferably set to 10 nm to 100 nm. By setting in this way, a magnetic field having a low magnetic field intensity out of the recording magnetic field flowing out from the main magnetic pole 21 and spreading toward the trailing side does not reach the deep part of the soft magnetic backing layer 42 and enters the recording layer 43 in an oblique direction. In addition, it is sucked into the auxiliary magnetic pole tip 30. A magnetic field incident at an angle from the direction perpendicular to the film surface of the recording layer easily reverses the magnetization of the recording layer 43 and increases the effective magnetic field strength. Accordingly, the gradient in the magnetic field strength Ha on the trailing side at the on-track position facing the main magnetic pole 21 shown in FIG. As a result, the magnetic field strength distribution of the recording magnetic field becomes good, and the recording resolution of the recording element is improved.

Auxiliary pole tip 30 is set in the range (from the medium facing surface 11 length of Z ₁ direction) depth is, for example, 50 nm to 300 nm. As a result, the magnetic field sucked into the auxiliary magnetic pole tip 30 is increased, and the magnetic field strength distribution of the recording magnetic field from the main magnetic pole 21 is improved.

The high Bs portion 32 is made of a soft magnetic ferromagnetic material containing Fe, Ni, or Co. Ferromagnetic material of the high Bs 32, CoFe, CoNiFe or is preferably selected from ferromagnetic material mainly composed of NiFe,, in that a high saturation magnetic flux density, CoNiFe, CoFeB, FeCoAlO or Ni ₅₀ Fe, ₅₀ is more preferred.

  On the other hand, the first low Bs portion 31 and the second low Bs portion 33 are made of a soft magnetic ferromagnetic material having a saturation magnetic flux density lower than that of the high Bs portion 32 ferromagnetic material. The first low Bs portion 31 and the second low Bs portion 33 are made of NiFe or NiFe—X, and X is selected from a ferromagnetic material containing at least one selected from the group consisting of Ta, Mo, Cr, and Cu. preferable.

  The first low Bs portion 31 and the second low Bs portion 33 are NiFe or NiFe-X having a lower Fe content than the high Bs portion 32 when the high Bs portion 32 is made of a ferromagnetic material mainly composed of NiFe. Preferably it consists of. By using such a ferromagnetic material, the first low Bs portion 31 and the second low Bs portion 33 can set the saturation magnetic flux density lower than that of the high Bs portion 32. In addition, since the lattice matching between the first low Bs portion 31 and the high Bs portion 32 is good, the high Bs portion 32 with good crystallinity can be formed on the first low Bs portion 31, and the coercive force of the high Bs portion 32 can be increased. The saturation magnetic flux density can be improved while being reduced.

The ratio between the saturation magnetic flux density Bs _H of the high Bs portion 32 and the saturation magnetic flux density Bs _{L of} the first low Bs portion 31 and the second low Bs portion 33 is a viewpoint of a material that can be selected from the ferromagnetic materials actually obtained. It is set in the range of Bs _H / Bs _L = 1.4~2.4 from is preferred.

  According to the present embodiment, the first low Bs portion 31 and the high Bs portion 32 are arranged in this order from the main magnetic pole 21 side on the trailing side of the main magnetic pole 21, and the track width direction and trailing of the high Bs portion 32 are arranged. The second low Bs portion 33 is disposed on the side. By forming the high Bs portion 32 to have a predetermined width, the magnetic field strength absorbed by the sub magnetic pole 23 is reduced while maintaining the steep gradient of the recording magnetic field on the trailing side of the main magnetic pole 21 so that the off-track position is maintained. Side erase can be suppressed. As a result, it is possible to suppress the deterioration of the S / N ratio due to the side erase and increase the recording density.

  Next, a method for manufacturing the magnetic head for perpendicular recording according to the present embodiment will be described. The manufacturing method of the magnetic head for perpendicular recording is composed of an element forming process, a wafer cutting process, a rover rough polishing process, an air bearing surface finish polishing process, an air bearing surface pad processing process, a row bar cutting process, and the like. It is formed by a manufacturing method. A description of these methods will be omitted, and a method for forming the sub-magnetic pole of the recording element in the element forming step will be described below with reference to FIGS. 5 (A) and 5 (B).

  5A and 5B are views showing a manufacturing process of the magnetic head for perpendicular recording according to the first embodiment.

  5A, the nonmagnetic portion 12, the reproducing element 15, and the nonmagnetic portion 22 shown in FIG. 2 are sequentially formed on the wafer by a known method. Next, the auxiliary magnetic pole and the main magnetic pole 21 are formed in the nonmagnetic portion 22, then the nonmagnetic portion covering the auxiliary magnetic pole and the main magnetic pole 21 is formed, and the surface thereof is flattened by a CMP (chemical mechanical polishing) method.

  5A, the first low Bs portion 31 made of the above-described material such as NiFe is formed on the nonmagnetic portion 22 by electroplating, electroless plating, sputtering, or the like. In the case where the first low Bs portion 31 is formed by electroplating, a plating seed layer such as a Ti film or Cu film is formed on the surface of the nonmagnetic portion 22 by sputtering or the like.

  5A, a resist film 51 is further formed on the first low Bs portion 31, and the resist film 51 is patterned by a photolithography method, so that the first low Bs portion 31 is positioned above the main magnetic pole 21. An opening 51-1 exposing the surface is formed. The opening 51-1 is formed such that the center line in the track width direction coincides with the center line of the main magnetic pole 21 in the track width direction.

  5A, a soft magnetic film 32a made of the above-described high Bs portion material such as NiFe is formed by electroplating, electroless plating, sputtering, or the like using the resist film 51 as a mask. In the case where the soft magnetic film 32a is formed by electroplating, the first low Bs portion 31 is used as a plating seed layer to form a film by applying an electric field.

  Next, in the process of FIG. 5B, the resist film 51 of FIG. 5A and the soft magnetic film 32a thereon are removed by a lift-off method. In this way, the high Bs portion 32 is formed.

  In the step of FIG. 5B, a second low Bs portion 33 that covers the surface of the first low Bs portion 31 and the high Bs portion 32 is further formed by electroplating, electroless plating, sputtering, or the like. Next, the surface of the second low Bs portion 33 is planarized by CMP. Thus, the sub magnetic pole tip is formed.

  Next, the sub magnetic pole connecting portion 34, the sub magnetic pole main portion 35, the recording coil, the yoke, and the like shown in FIGS. 2 and 3 are formed. Thus, a recording element is formed.

  In this manufacturing method, the first low Bs portion 31 is formed by sputtering, and the high Bs portion 32 is selectively formed by electroplating using the first low Bs portion 31 as a plating seed layer. Since it is not necessary to separately form a plating seed layer in order to form the high Bs portion 32, the process can be simplified. In addition, since the first low Bs portion 31 and the high Bs portion 32 can be formed without using dry etching such as RIE (reactive ion etching), the first low Bs portion 31 and the high Bs portion 32 are formed by ions or plasma. There is no damage. Therefore, the first low Bs portion 31 and the high Bs portion 32 having good magnetic properties can be formed.

  Further, the sub-magnetic pole of the recording element may be formed by the method described below.

  6A to 6C are views showing a modification of the manufacturing process of the perpendicular recording magnetic head according to the first embodiment.

  In the step of FIG. 6A, the nonmagnetic portion 22 is flattened in the same manner as in the above-described step of FIG. 5A, and then the electroplating method and electroless plating method are performed on the nonmagnetic portion 22. Then, the soft magnetic film 31a made of the material of the first low Bs portion described above is formed by sputtering or the like. Here, the thickness of the soft magnetic film 31a is set to be equal to the sum of the thicknesses of the first low Bs portion and the high Bs portion 32 shown in FIG.

  In the step of FIG. 6A, a resist film 52 is further formed on the soft magnetic film 31a, and the resist film 52 is patterned by a photolithography method to form an opening 52-1 at a position above the main magnetic pole 21. To do. The opening 52-1 is formed so that the center line in the track width direction coincides with the center line in the track width direction of the main pole 21.

  6A, the soft magnetic film 31a is further etched by ion milling using Ar ions or the RIE method using the resist film 52 as a mask to form the recess 31a-1.

  Next, in the step of FIG. 6B, the resist film 52 of FIG. 6A is removed, the soft magnetic film 31a is covered by electroplating, electroless plating, sputtering, etc., and the recess 31a-1 is filled. A soft magnetic film 32b made of a material having a high Bs portion is formed.

  6C, the soft magnetic film 32b is planarized by CMP until the surface of the soft magnetic film 31a is exposed. By this planarization, the low Bs portion 31c in which a part of the first low Bs portion 31 and the second low Bs portion 33 shown in FIG. 3 are integrated is formed, and the high Bs portion 32 is formed.

  In the step of FIG. 6C, a low Bs portion 31d that covers the surfaces of the low Bs portion 31c and the high Bs portion 32 is further formed by electroplating, electroless plating, sputtering, or the like. The material of the low Bs portion 31d is selected from the same materials as the material of the second low Bs portion 33 shown in FIG. Thus, the sub magnetic pole tip is formed.

  In this manufacturing method, the first low Bs portion 31 and the second low Bs portion 33 shown in FIG. 3 are continuously formed at the position of the interface between the first low Bs portion 31 and the high Bs portion 32. It is possible to eliminate concerns about the occurrence of magnetic anomalies such as the occurrence of domain walls due to the interface in the region where the magnetic field strength to be sucked is high.

  Next, the magnetic field strength distribution formed by the recording elements constituting the perpendicular recording magnetic head according to the present embodiment was obtained by simulation.

  FIGS. 7A and 7B are diagrams showing dimensions of the recording elements constituting the examples and comparative examples.

Referring to FIG. 7A, the configuration of the recording element of the example is the same as that of FIG. In the simulation, the magnetic field strength distribution at the center position of the recording layer was obtained by varying the saturation magnetic flux density, the thickness TL3, and the width WT of the high Bs portion 32 of the sub magnetic pole. Specifically, from the obtained magnetic field strength distribution, the maximum value of the magnetic field strength in the direction perpendicular to the film surface at the off-track position indicated by the broken line OFT separated from the track center line indicated by the alternate long and short dash line by the distance L _OF. Asked.

  Further, from the obtained magnetic field strength distribution, the magnetic field gradient with respect to the trailing direction at the magnetic field strength at which the recording layer causes magnetization reversal on the trailing side on the track center line CL was obtained. The magnetic field intensity causing the magnetization reversal of the recording layer corresponds to Ha shown in FIG. 4B, and the gradient of the magnetic field is a gradient with respect to the trailing direction at the point TRA.

  In the simulation, the main magnetic pole 21 was set to have a width (trailing side length) of 110 nm, a leading side length of 71.5 nm, a thickness of 220 nm, and a saturation magnetic flux density of 2.4 T. . For the tip of the sub magnetic pole, the thickness TL1 of the first low Bs portion 31 is 100 nm, the thickness TL2 of the second low Bs portion 33 is 500 nm, and the saturation magnetic flux density of the first low Bs portion 31 and the second low Bs portion 33 Was set to 1.0T. The depth of the tip of the sub magnetic pole (the length in the depth direction of the tip of the sub magnetic pole 30 shown in FIG. 3) was 130 nm. The recording coil and recording current conditions were set to 0.25 AT (ampere turn). These conditions were applied to Examples 1 to 8 shown in FIG.

  For comparison, the simulation was performed under the same conditions as in the example for the recording element of the comparative example having the configuration shown in FIG. The recording element of the comparative example is the same as the recording element of the example of FIG. 7A except that the high Bs portion 113 extends in the track width direction like the first low Bs portion 31. These conditions were applied to Comparative Examples 1 and 2 shown in FIG.

  FIG. 8 is a diagram showing the recording magnetic field characteristics of the recording elements constituting the example and the comparative example. In FIG. 8, the maximum magnetic field strength at the off-track position is shown as a relative value with the maximum value at the off-track position of the recording element of Comparative Example 1 being 100%. Further, the magnetic field gradient at the recording track position is shown as a relative value with the magnetic field gradient of the recording element of Comparative Example 1 being 100%.

  Referring to FIG. 8, in Examples 1 to 4 and Comparative Example 1, the saturation magnetic flux density of the high Bs portion 32 and the high Bs portion 113 shown in FIG. It is. In Examples 1 to 4, the thickness TL3 of the high Bs portion 32 is set to 500 nm and 250 nm, and the width WT is set to 110 nm, which is the same as the width of the main magnetic pole 21, and 220 nm, which is twice as large. The off-track position OFT was set at a position 200 nm from the track center line CL. Further, the recording magnetic field strength at the recording track position obtained by this simulation is 13.2 kOe, the maximum value at the off-track position in Comparative Example 1 is 5.55 kOe, and the magnetic field gradient at the recording track position in Comparative Example 1 is 246 Oe. / Nm.

  In Examples 1 to 4, the maximum magnetic field strength at the off-track position is reduced by about 20% compared to Comparative Example 1. Further, the magnetic field gradient at the recording track position is about 5% lower than that of Comparative Example 1, and there is almost no deterioration. Therefore, when the width WT of the high Bs portion 32 is equal to or twice the width of the main magnetic pole 21, the maximum at the off-track position when the recording magnetic field is applied without causing deterioration of the magnetic field gradient of the recording track. It can be seen that the magnetic field strength can be reduced.

  Examples 5 to 8 and Comparative Example 2 are cases where the saturation magnetic flux density of the high Bs portion 32 and the high Bs portion 113 shown in FIG. 7A or 7B is 2.4 T, respectively. In Examples 5 to 8, the thickness TL3 of the high Bs portion 32 is changed to 500 nm and 250 nm, and the width WT is changed to 110 nm, which is the same as the width of the main magnetic pole 21, and 220 nm, which is twice as large.

  In Examples 1 to 4, the maximum magnetic field strength at the off-track position is reduced by about 14% to 25 compared to Comparative Example 2. Further, the magnetic field gradient at the recording track position is about 3 to 6% lower than that of Comparative Example 2, and there is almost no deterioration. Therefore, even when the saturation magnetic flux density of the high Bs portion 32 is 2.4 T, when the width WT of the high Bs portion 32 is equal to or twice the width of the main magnetic pole 21, the recording track It can be seen that the maximum magnetic field strength at the off-track position when the recording magnetic field is applied can be reduced without causing deterioration of the magnetic field gradient.

  According to Examples 1 to 8, even when the saturation magnetic flux density of the high Bs portion 32 is 1.4T or 2.4T, the width WT of the high Bs portion 32 is set to the main magnetic pole as compared with the comparative example 1 and the comparative example 2. It was confirmed that the maximum magnetic field strength at the off-track position when the recording magnetic field was applied could be reduced without degrading the magnetic field gradient of the recording track when the width was equal to or twice the width of 21.

(Second Embodiment)
Next, a magnetic memory device according to the second embodiment of the present invention will be described.

  FIG. 9 is a diagram showing a main part of a magnetic memory device according to the second embodiment of the present invention. Referring to FIG. 9, the magnetic storage device 60 according to the present embodiment includes a housing 61 and a magnetic disk 62, a perpendicular recording magnetic head 63, an actuator unit 64, and the like stored in the housing 61. . The magnetic disk 62 is fixed to the hub 65 and is driven by a spindle motor (not shown). The perpendicular recording magnetic head 63 has a base fixed to the arm 66 and is attached to the actuator unit 64 via the arm 66. The perpendicular recording magnetic head 63 is rotated in the radial direction of the magnetic disk 62 by the actuator unit 64. An electronic board (not shown) for performing recording / reproduction control, magnetic head position control, spindle motor control, and the like is provided on the back side of the housing 61.

  As shown in FIG. 3, the magnetic recording medium 63 is a perpendicular magnetic recording medium. For example, the magnetic recording medium 63 is formed by laminating a recording layer including a soft magnetic underlayer and a perpendicular magnetization film on a substrate in this order. Further, a nonmagnetic intermediate layer may be provided between the soft magnetic backing layer and the recording layer, and a protective film and further a lubricating layer may be provided on the recording layer.

  The perpendicular recording magnetic head 63 is the perpendicular recording magnetic head according to the first embodiment described above. The perpendicular recording magnetic head 63 is provided with an element portion (not shown because it is minute) on a head slider 68 at the tip thereof. The element unit is provided with the recording element described in the first embodiment.

  The basic configuration of the magnetic storage device 60 is not limited to that shown in FIG. The magnetic recording medium used in the present invention is not limited to the magnetic disk 62. For example, the magnetic storage device 60 may be a helical scan type or a lateral type magnetic tape device. In this case, the perpendicular recording magnetic head 63 is mounted on the cylinder head in the case of the helical scan type, and in the case of the lateral type, a plurality of vertical recording magnetic heads 63 are provided. A recording magnetic head is mounted in the tape width direction.

  According to the present embodiment, the recording element of the perpendicular recording magnetic head 63 maintains the recording magnetic field gradient on the trailing side of the main magnetic pole in a steep state while reducing the magnetic field strength absorbed by the sub magnetic pole. Side erasure at the track position can be suppressed. As a result, it is possible to suppress the deterioration of the S / N ratio due to the side erase and increase the recording density. As a result, a magnetic storage device capable of increasing the recording density can be realized.

  The preferred embodiment of the present invention has been described in detail above. However, the present invention is not limited to the specific embodiment, and various modifications can be made within the scope of the present invention described in the claims.・ Change is possible.

In addition, the following additional notes are disclosed regarding the above description.
(Supplementary Note 1) A main magnetic pole that is arranged along the recording direction and applies a recording magnetic field, a sub magnetic pole that faces the main magnetic pole and serves as a return path of the recording magnetic field, and the main magnetic pole and the sub magnetic pole are magnetically connected. A perpendicular recording magnetic head comprising a recording element having a yoke,
The sub magnetic pole has a sub magnetic pole tip on the side facing the main magnetic pole,
The auxiliary magnetic pole tip is in order from the main magnetic pole side,
A first soft magnetic portion extending in a width direction perpendicular to the recording direction;
A second soft magnetic portion that is in contact with the first soft magnetic portion and disposed substantially symmetrically in the width direction with respect to the center line on a center line along the recording direction of the main magnetic pole; A third soft magnetic part on both sides in the width direction of the part,
The perpendicular recording magnetic head according to claim 1, wherein the second soft magnetic part is made of a ferromagnetic material having a saturation magnetic flux density higher than that of the first soft magnetic part and the third soft magnetic part.
(Supplementary Note 2) The sub magnetic pole is disposed on the trailing side with respect to the main magnetic pole, the sub magnetic pole connecting portion along the recording direction on the trailing side of the sub magnetic pole tip, and the sub magnetic pole connected to the yoke Have the main part in this order,
The sub magnetic pole connecting portion is in contact with the main portion of the sub magnetic pole at the base, and is in contact with the front end of the sub magnetic pole.
2. The perpendicular recording magnetic head according to claim 1, wherein the tip of the auxiliary magnetic pole has a shorter length in the direction perpendicular to the medium facing surface than the auxiliary magnetic pole connection.
(Supplementary note 3) The perpendicular recording magnetic head according to Supplementary note 1 or 2, wherein a distance between the first soft magnetic portion and the main magnetic pole is set in a range of 10 nm to 100 nm.
(Supplementary Note 4) Of the supplementary notes 1 to 3, wherein the width of the second soft magnetic portion is equal to or greater than twice the width of the main magnetic pole facing the sub magnetic pole tip. A magnetic head for perpendicular recording according to any one of the above.
(Supplementary Note 5) The saturation magnetic flux density of the ferromagnetic material of the second soft magnetic part is 140% or more with respect to the saturation magnetic flux density of the ferromagnetic material of the first soft magnetic part and the third soft magnetic part. The magnetic head for perpendicular recording according to any one of appendices 1 to 4, wherein the magnetic head is 240% or less.
(Appendix 6) The perpendicular recording magnetism according to any one of appendices 1 to 5, wherein the length of the second soft magnetic portion in the recording direction is set in a range of 50 nm to 500 nm. head.
(Supplementary note 7) Of the supplementary notes 1 to 6, wherein the ferromagnetic material of the second soft magnetic part is a material mainly comprising any one of the group consisting of CoNiFe, CoFe, and NiFe. A magnetic head for perpendicular recording according to any one of the above.
(Supplementary Note 8) The ferromagnetic material of the first soft magnetic part and the third soft magnetic part is from NiFe or NiFe-X (including at least one selected from the group consisting of X = Ta, Mo, Cr, and Cu). The magnetic head for perpendicular recording according to any one of appendices 1 to 7, characterized in that:
(Supplementary note 9) The ferromagnetic material of the second soft magnetic part is made of a material mainly composed of NiFe, and the ferromagnetic material of the first soft magnetic part and the third soft magnetic part has an Fe concentration of Supplementary note 1 comprising NiFe or NiFe-X (including at least one selected from the group consisting of Ta = Mo, Cr and Cu) lower than the Fe concentration of the ferromagnetic material of the second soft magnetic part The magnetic head for perpendicular recording as described in any one of -7.
(Additional remark 10) The perpendicular recording magnetic head according to additional remark 8 or 9, wherein the first soft magnetic portion and the third soft magnetic portion are made of the same ferromagnetic material.
(Supplementary note 11) A method of manufacturing a magnetic head for perpendicular recording comprising a recording element having a main magnetic pole for applying a recording magnetic field arranged along a recording direction and a sub-magnetic pole serving as a return path for the recording magnetic field,
Forming a sub-magnetic pole on the main magnetic pole,
The step of forming the sub magnetic pole includes
Forming a nonmagnetic layer covering the main pole;
Forming a first soft magnetic portion on the nonmagnetic layer;
A process of selectively forming a second soft magnetic portion on the surface of the first soft magnetic portion;
Forming a third soft magnetic part that covers the surface of the first soft magnetic part and the second soft magnetic part, and a method of manufacturing a magnetic head for perpendicular recording.
(Additional remark 12) The process which forms a said 2nd soft-magnetic part,
A resist film having an opening exposing the surface of the first soft magnetic part is formed above the main pole on the surface of the first soft magnetic part, and a second film is formed on the exposed first soft magnetic part. 12. The method of manufacturing a magnetic head for perpendicular recording according to appendix 11, wherein a soft magnetic layer serving as a soft magnetic portion is deposited and the soft magnetic layer on the resist film is removed together with the resist film.
(Supplementary Note 13) The process of forming the second soft magnetic part is as follows:
A resist film having an opening exposing the surface of the first soft magnetic part is formed above the main pole on the surface of the first soft magnetic part, and the first soft magnetic part is formed using the resist film as a mask. 12. The method of manufacturing a magnetic head for perpendicular recording according to appendix 11, wherein a groove is formed by etching, and the groove is filled with a ferromagnetic material that becomes the second soft magnetic portion.
(Supplementary Note 14) A magnetic recording medium in which a substrate and a recording layer made of a soft magnetic backing layer and a perpendicular magnetization film are sequentially stacked on the substrate;
A magnetic storage device comprising: the perpendicular recording magnetic head according to any one of appendices 1 to 10.

It is a figure which shows the structure of the conventional magnetic head for perpendicular recording. 1 is a cross-sectional view of an element portion of a magnetic head for perpendicular recording according to a first embodiment of the present invention. FIG. 3 is a diagram of the recording element shown in FIG. 2 viewed from the medium facing surface side. (A) And (B) is a figure for demonstrating the effect of this invention. (A) And (B) is a figure which shows the manufacturing process of the magnetic head for perpendicular recording based on 1st Embodiment. (A)-(C) are figures which show the modification of the manufacturing process of the magnetic head for perpendicular recording based on 1st Embodiment. (A) And (B) is a figure which shows each dimension of the recording element which comprises an Example and a comparative example. It is a figure which shows the recording magnetic field characteristic of the recording element which comprises an Example and a comparative example. It is a top view which shows the principal part of the magnetic memory device based on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic head for perpendicular recording 11 Medium facing surface 12, 18, 22 Nonmagnetic part 15 Reproducing element 16 Lower shield layer 17 MR film 19 Upper shield layer 20 Recording element 21 Main magnetic pole 23 Sub magnetic pole 24 Auxiliary magnetic pole 25 Yoke 26 Recording coil 30 Sub magnetic pole tip 31 First low Bs part 32 High Bs part 33 Second low Bs part 34 Sub magnetic pole connection part 35 Sub magnetic pole main part 51, 52 Resist film 60 Magnetic storage device

Claims (5)

A recording having a main magnetic pole for applying a recording magnetic field, a sub magnetic pole facing the main magnetic pole and serving as a return path for the recording magnetic field, and a yoke for magnetically connecting the main magnetic pole and the sub magnetic pole, arranged along the recording direction A perpendicular recording magnetic head comprising an element,
The sub magnetic pole has a sub magnetic pole tip on the side facing the main magnetic pole,
The auxiliary magnetic pole tip is in order from the main magnetic pole side,
A first soft magnetic portion extending in a width direction perpendicular to the recording direction;
A second soft magnetic portion that is in contact with the first soft magnetic portion and disposed substantially symmetrically in the width direction with respect to the center line on a center line along the recording direction of the main magnetic pole; A third soft magnetic part on both sides in the width direction of the part,
The perpendicular recording magnetic head according to claim 1, wherein the second soft magnetic part is made of a ferromagnetic material having a saturation magnetic flux density higher than that of the first soft magnetic part and the third soft magnetic part. The sub magnetic pole is disposed on the trailing side with respect to the main magnetic pole, and the sub magnetic pole connecting portion and the sub magnetic pole main portion connected to the yoke are arranged along the recording direction on the trailing side of the sub magnetic pole tip. In order,
The sub magnetic pole connecting portion is in contact with the main portion of the sub magnetic pole at the base, and is in contact with the front end of the sub magnetic pole.
2. The magnetic head for perpendicular recording according to claim 1, wherein the tip of the auxiliary magnetic pole has a shorter length in the direction perpendicular to the medium facing surface than the auxiliary magnetic pole connection.   3. The perpendicular recording according to claim 1, wherein the width of the second soft magnetic portion is equal to or greater than twice the width of the main magnetic pole facing the tip of the sub magnetic pole. Magnetic head.   The ferromagnetic material of the second soft magnetic part is made of a material mainly composed of NiFe, and the ferromagnetic material of the first soft magnetic part and the third soft magnetic part has an Fe concentration of the second soft magnetic part. The magnetic part is made of NiFe or NiFe-X (including at least one selected from the group consisting of Ta, Mo, Cr and Cu) lower than the Fe concentration of the ferromagnetic material of the magnetic part. A magnetic head for perpendicular recording according to any one of the above. A magnetic recording medium in which a substrate and a recording layer comprising a soft magnetic backing layer and a perpendicular magnetization film are sequentially laminated on the substrate;
A magnetic storage device comprising: the perpendicular recording magnetic head according to claim 1.

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