JP4644716B2 - Magnetic recording medium and magnetic recording method - Google Patents

Description

The present invention relates to a magnetic recording medium for recording magnetic information on a magnetic material formed on a substrate.

  In recent years, with the spread of broadband and the spread of digital home appliances, great expectations are placed on increasing the capacity of hard disks. The advancement of both the magnetic recording medium and magnetic head technologies supports the increase in capacity of the hard disk, that is, the increase in recording density. Of these, patterned media are actively studied as magnetic recording media aiming at higher recording density.

  Patterned media has a configuration in which a patterned magnetic bit is surrounded by a non-magnetic material, and each bit is composed of one magnetic dot. Therefore, the patterned media is highly resistant to the thermal fluctuation phenomenon. It is expected as a technology to solve the problem of disappearance.

The thermal fluctuation phenomenon is expressed by an index of K _u · V / kT (K _u : magnetic anisotropy energy density, V: recording bit volume, k: Boltzmann constant, T: absolute temperature), and the smaller this value, the greater the effect. Therefore, in a granular medium used for a conventional hard disk, the influence of thermal fluctuation is a big problem because the recording bit size of a high-density recording medium is reduced, that is, V is reduced.

  On the other hand, as a magnetic recording head for performing high density recording on a medium, a trailing shield type single magnetic pole type head having a single magnetic pole head provided with a trailing shield has been studied. As a document introducing the trailing shield type single magnetic pole head, in the last row of p57 of Non-Patent Document 1, a part of the generated recording magnetic field is absorbed by the trailing shield, so that the magnetic field distribution becomes steep. It is described that high density recording is possible by increasing the magnetic field gradient.

  Also in Non-Patent Document 2, according to the graph (FIG. 2) showing the recording magnetic field of the single magnetic pole head and the trailing shield type single magnetic pole head depending on the distance in the track down direction from the trailing edge. It is described that the perpendicular recording magnetic field applied to the medium sharply decreases in the trailing shield type single magnetic pole head as compared with the conventional single magnetic pole head as it moves away from the edge in the track down direction.

  Patent Document 1 discloses a heat-assisted magnetic recording medium in which a magnetic recording layer for recording magnetization information is laminated on a magnetic anisotropy induction auxiliary layer having a negative coefficient of thermal expansion ( Paragraph [0008]). According to Patent Document 1, when a laser beam is irradiated at the time of recording, a recording magnetic domain having a small crosslight is formed in a locally heated portion by magnetic anisotropy energy induced by the magnetic anisotropy induction auxiliary layer. It can be formed on the magnetic recording layer (paragraph [0044]).

Non-Patent Document 3 describes a magnetostrictive actuator in which a TbFe alloy of a positive magnetostrictive thin film material and a SmFe alloy of a negative magnetostrictive thin film material are combined.
FUJITSU. 58,1, p53-60 (01,2007) JOURNAL OF APPLIED PHYSICS99,08S304 (2006) Journal of Japan Society for Precision Engineering VOL. 60, no. 12, 1994, p1699-1702. JP 2007-26511 A

  However, by using a trailing shield type single magnetic pole head as a magnetic recording head as described in Non-Patent Documents 1 and 2, the recording density has been improved, but the saturation magnetic flux of the magnetic recording head has been improved. Limits have been seen in improving the density and reducing the size of the magnetic recording head that directly reflects the size of the recording magnetic domain.

  For this reason, as the recording density of magnetic recording media increases in the future, it will become more difficult to stably record high-density magnetic domains on a medium with high coercive force without erroneously recording adjacent magnetic domains. Is expected.

  Further, in Patent Document 1, since a material that thermally expands is used for the magnetic anisotropy induction auxiliary layer, a heat source is always necessary. Therefore, it cannot be used for a magnetic recording medium other than a light (heat) assisted magnetic recording medium that requires a heat source.

  Non-Patent Document 3 does not describe or suggest a trailing shield type head.

  In order to solve the above problems, an object of the present invention is to provide a magnetic recording medium capable of recording high-density magnetic information and preventing erroneous recording of magnetic information.

  In order to solve the above problems, a magnetic recording medium of the present invention is a magnetic recording medium comprising a magnetic layer to which magnetism is applied on a substrate, wherein the magnetic layer is parallel to the film surface of the magnetic layer. And a plurality of magnetic recording portions, each of which is recorded with information by the applied magnetism, and a magnetic layer having a relatively large magnetic anisotropy in a direction perpendicular to the film surface of the magnetic layer. A first stress applying portion made of a magnetic material having a relatively large magnetic anisotropy in a direction parallel to the film surface of the magnetic layer as compared to a direction perpendicular to the film surface of the magnetic layer, and at least information is recorded. The plurality of magnetic recording portions and the first stress applying portion are alternately arranged along the track, and the magnetostriction constants of the magnetic recording portion and the first stress applying portion are Is positive.

  According to this, the magnetic recording part and the first stress applying part are alternately arranged adjacent to each other along a track on which information is recorded. Then, a magnetic field (perpendicular magnetism) having a relatively large magnetic field component in the direction perpendicular to the film surface compared to the magnetic field component in the direction parallel to the film surface is applied to the magnetic recording unit, thereby Information is magnetically recorded on the part. The perpendicular magnetism applied to the magnetic recording unit on which magnetic recording is performed is a magnetism having a strong magnetic field component perpendicular to the film surface to the extent that information is magnetically recorded. A magnetic field component may be included.

  Here, among the magnetic recording units, the magnetic recording unit in which the perpendicular magnetic information is recorded is defined as a first magnetic recording unit. The second magnetic recording unit is a next magnetic recording unit arranged via the first stress applying unit and in which perpendicular magnetic information has already been recorded.

  Of the first stress applying portions, the first stress applying portion disposed between the first magnetic recording portion and the second magnetic recording portion is replaced with the first first stress applying portion. The stress is applied. Further, the first stress applying unit is disposed through the second magnetic recording unit, and is disposed adjacent to the second magnetic recording unit, and the first first stress applying unit is provided. A first stress applying part formed at a position sandwiching the second magnetic recording part together with the part is defined as a second first stress applying part.

  That is, immediately after the perpendicular magnetism is applied to the second magnetic recording portion, the perpendicular magnetism is applied to the first magnetic recording portion. When perpendicular magnetism is applied to the first magnetic recording unit, the first first stress applying unit, the second magnetic recording unit, and the second first stress applying unit A leakage magnetic field is applied to each. Here, the leakage magnetic field is a magnetic field around the perpendicular magnetism for performing magnetic recording on the magnetic recording unit, and includes more magnetic field components in a direction parallel to the film surface than the perpendicular magnetism.

  In the first first stress applying portion, the vicinity of the boundary surface with the second magnetic recording portion is more parallel to the film surface than the vicinity of the boundary surface with the first magnetic recording portion. A leakage magnetic field having a strong magnetic field component is applied. Further, a leakage magnetic field having a stronger magnetic field component in a direction parallel to the film surface than the leakage magnetic field applied to the first first stress applying unit is applied to the second first stress applying unit.

  Here, the first stress applying portion is made of a magnetic material having a relatively large magnetic anisotropy in a direction parallel to the film surface of the magnetic layer. Furthermore, the magnetostriction constant of the first stress applying part is positive. Accordingly, when a magnetic field including a magnetic field component in a direction parallel to the film surface is applied to the first stress applying part, the first stress applying part tends to extend in a direction parallel to the film surface. Magnetostriction occurs.

  Accordingly, since the first first stress applying part and the second first stress applying part generate magnetostriction that tends to extend in the parallel direction, the first first stress applying part, The second magnetic recording portion sandwiched between the second first stress applying portions is applied with a force for compressing in the direction parallel to the film surface.

  Further, the magnetic recording portion is made of a magnetic material having a relatively large magnetic anisotropy in a direction perpendicular to the film surface of the magnetic layer as compared with a direction parallel to the film surface. The magnetostriction constant of the magnetic recording part is positive. For this reason, when a force compressing in the direction parallel to the film surface is applied to the second magnetic recording unit from the first first stress applying unit and the second first stress applying unit. The magnetic anisotropy in the direction perpendicular to the film surface is improved by the inverse magnetostrictive effect. Thereby, the perpendicular magnetic anisotropy energy density is improved.

  For this reason, when perpendicular magnetic information is recorded in the first magnetic recording unit, even if a leakage magnetic field is applied to the second magnetic recording unit, the magnetic data already recorded in the second magnetic recording unit is recorded. It is possible to prevent the information from being affected.

  Therefore, it is possible to provide a magnetic recording medium capable of recording high-density magnetic information and preventing erroneous recording of magnetic information.

  In the magnetic recording medium of the present invention, it is preferable that each of the plurality of magnetic recording portions is separated from each other, and a cross section in a direction parallel to the film surface is formed as a closed region.

  With the above configuration, it is possible to prevent the magnetic information recorded in each of the plurality of magnetic recording units from affecting the magnetic information recorded in other magnetic recording units.

  In the magnetic recording medium of the present invention, a second stress applying part is further formed in each of the plurality of magnetic recording parts in the film thickness direction in the magnetic recording part. Is preferably made of a magnetic material having a relatively large magnetic anisotropy in the direction parallel to the film surface of the magnetic layer as compared with the direction perpendicular to the film surface, and has a negative magnetostriction constant.

  With the above configuration, when recording perpendicular magnetic information on the first magnetic recording unit, the second stress applying unit formed in the film thickness direction (perpendicular to the film surface) of the second magnetic recording unit A leakage magnetic field is also applied.

  Here, the second stress applying part formed in the film thickness direction in the magnetic recording part only needs to be formed in the film thickness of the magnetic recording part. That is, the second stress applying portion may be formed in a lower portion of the magnetic recording portion (a film surface portion on the side where the substrate is provided), and an upper portion of the magnetic recording portion (the substrate). May be formed in the middle layer portion (portion between the lower portion and the upper portion).

  According to the above configuration, the second stress applying portion has a negative magnetostriction constant. As a result, when a magnetic field including a magnetic field component in a direction parallel to the film surface is applied to the second stress applying part, the second stress applying part compresses in a direction parallel to the film surface. Occurs. The second stress applying part is formed such that a side surface in a direction perpendicular to the film surface is surrounded by the first stress applying part. For this reason, the compression force is applied to the side surface in the direction perpendicular to the film surface from the first stress applying portion to which the leakage magnetic field is applied.

  As described above, according to the above configuration, the second magnetic recording portion is further strongly applied with a compressive force in a direction parallel to the film surface, so that the perpendicular magnetic anisotropy is further improved by the inverse magnetostriction effect. In addition, erroneous recording on the adjacent magnetic recording portions can be prevented.

  In the magnetic recording medium of the present invention, it is preferable that a nonmagnetic portion made of a nonmagnetic material is further formed between the magnetic recording portion and the first stress applying portion.

  According to this, the magnetic coupling generated between the magnetic recording part and the adjacent first stress applying part is broken. For this reason, the perpendicular magnetic anisotropy of the magnetic recording portion does not weaken the magnetic anisotropy component in the parallel direction in the first stress applying portion. Thereby, the stress due to the magnetostriction in the direction parallel to the film surface of the first stress applying portion when applying magnetic information is not reduced.

  That is, since the perpendicular magnetic anisotropy of the second magnetic recording portion can be stably improved by the inverse magnetostriction effect, erroneous recording on the second magnetic recording portion can be prevented. Furthermore, since the magnetic coupling between the magnetic recording portion and the adjacent first stress applying portion is broken, the magnetic anisotropy in the direction parallel to the film surface of the first stress applying portion is balanced. Thus, it is possible to prevent the magnetization direction in the magnetic recording unit from being inclined from the vertical direction and to record magnetic information stably.

  In the magnetic recording medium of the present invention, the non-magnetic portion is further formed between each of the plurality of magnetic recording portions and above or below the first stress applying portion. Is preferred.

  According to this, compared with the case where the said nonmagnetic part is not formed, the thickness of said 1st stress provision part can be made thin. Here, as described above, the first stress applying portion is made of a magnetic material having a relatively large magnetic anisotropy in the direction parallel to the film surface as compared to the direction perpendicular to the film surface. For this reason, the direction in which the first stress applying portion has magnetization in the direction parallel to the film surface is more stable in terms of energy. Further, by reducing the thickness of the first stress applying portion, it is possible to stabilize the magnetic anisotropy in the direction parallel to the film surface by the shape magnetic anisotropy.

  Therefore, the perpendicular magnetic anisotropy of the second magnetic recording portion is improved by the inverse magnetostriction effect, and erroneous recording on the second magnetic recording portion can be prevented. Further, since the magnetic coupling is broken at the position where the nonmagnetic portion is formed, the magnetic recording information recorded in the first magnetic recording portion and the second magnetic recording portion is exchange coupling force. Therefore, it is possible to prevent the images from being transferred to each other.

  In the magnetic recording medium of the present invention, it is preferable that the magnetic bodies of the magnetic recording portion, the first stress applying portion, and the second stress applying portion are all amorphous magnetic materials.

  According to this, as compared with the case where a crystalline metal material is used for the magnetic material, the individual magnetic recording portions in the magnetic recording medium or the like due to lattice defects or unintentional crystal orientation changes in the recording bits. Each of the magnetic recording unit, the first stress applying unit, and the second stress applying unit has the same magnetism without causing dispersion of magnetic characteristics of the first stress applying unit and the second stress applying unit. Since it exhibits the characteristics, it is suitable for providing a magnetic recording medium having stable performance.

  In the magnetic recording medium of the present invention, the magnetic material of the magnetic recording part further includes at least one rare earth metal selected from Gd, Ho, Tb, and Dy, and at least one 3d transition metal selected from Fe and Co. It is preferable to comprise.

  According to this, it becomes a ferrimagnetic material in which the magnetizations of the rare earth metal and the 3d transition metal are aligned in antiparallel, and the magnetic recording part having a positive magnetostriction constant having a large absolute value at room temperature can be obtained. For this reason, it is possible to increase the perpendicular magnetic anisotropy energy density that appears when a stress in a direction parallel to the film surface is applied to the magnetic recording portion.

  In addition, by adjusting the alloy composition of the magnetic recording portion and setting a compensation point near room temperature, a high coercive force can be obtained at room temperature, so that recording information can be stably maintained and the Curie temperature can be set relatively low, It is possible to provide a magnetic recording medium including the above-described magnetic recording unit suitable for heat-assisted magnetic recording. In addition, an alloy of Tb, Fe, and Co can obtain high perpendicular magnetic anisotropy energy, and is therefore suitable for use as the magnetic recording portion of the magnetic recording medium of the present application. At this time, by using an alloy of Tb, Fe, and Co having strong perpendicular magnetic anisotropy for the magnetic recording portion, the magnetization in the direction perpendicular to the film surface of the magnetic recording portion is changed to the first stress applying portion and the first stress applying portion. It is possible to prevent tilting under the influence of magnetic anisotropy in the parallel direction with respect to the film surface of the second stress applying portion.

  In the magnetic recording medium of the present invention, the magnetic material of the first stress applying portion is at least one rare earth metal selected from Gd, Ho, Tb, and Dy, and at least one selected from Fe and Co. It preferably comprises a 3d transition metal.

  According to this, the first stress applying part having a large absolute value and a positive magnetostriction constant at room temperature can be obtained. In addition, by adjusting the alloy composition of the first stress applying portion, the magnetic anisotropy in the direction parallel to the film surface is relatively stronger than in the vertical direction, and a magnetic field in the direction parallel to the film surface is applied. The coercive force at the time can be set small, and the coercive force when the magnetic field is applied in the direction perpendicular to the film surface can be set large.

  Accordingly, when a magnetic field having a component parallel to the film surface is applied to the first stress applying part, magnetostriction in a direction parallel to the film surface is generated, and the first stress applying part is adjacent to the first stress applying part. By applying a compressive stress in a direction parallel to the film surface to the magnetic recording portion, the perpendicular magnetic anisotropy of the magnetic recording portion adjacent to the first stress applying portion is improved by the inverse magnetostriction effect, and the adjacent magnetic recording It is possible to prevent erroneous recording on the part.

  In the magnetic recording medium of the present invention, it is preferable that the magnetic body of the second stress applying portion is made of SmFe.

  According to this, the second stress applying part having a large absolute value and a negative magnetostriction constant at room temperature can be obtained. In addition, by adjusting the alloy composition of the second stress applying portion, the magnetic anisotropy in the direction parallel to the film surface is relatively stronger than in the vertical direction, and a magnetic field in the direction parallel to the film surface is applied. The coercive force at the time can be set small, and the coercive force when the magnetic field is applied in the direction perpendicular to the film surface can be set large.

  Thereby, when a magnetic field having a component in a direction parallel to the film surface is applied to the second stress applying portion, magnetostriction in a direction parallel to the film surface is generated and adjacent to the second stress applying portion. By applying a compressive stress in a direction parallel to the film surface to the magnetic recording portion, the perpendicular magnetic anisotropy of the magnetic recording portion adjacent to the second stress applying portion is improved by the inverse magnetostriction effect, and the adjacent magnetic force is increased. It is possible to prevent erroneous recording on the recording unit.

  In the magnetic recording method of the present invention, it is preferable to record magnetic information by applying an external magnetic field while locally heating a part of the magnetic recording medium.

  According to this, a heat distribution with the central portion at a high temperature is generated on the magnetic recording medium with the first magnetic recording portion that records magnetic information as the central portion. As a result, in the first first stress applying portion adjacent to the periphery of the first magnetic recording portion, the temperature is raised to a high temperature in the vicinity of the boundary surface adjacent to the first magnetic recording portion. The magnetism is attenuated and the occurrence of magnetostriction is suppressed.

  On the other hand, in the vicinity of the boundary surface between the second magnetic recording portion and the first first stress applying portion, the temperature raised by the heat distribution is small. For this reason, since the amount of magnetism lost is small as compared with the vicinity of the boundary surface of the first first stress applying portion in contact with the central portion that is at a high temperature, magnetostriction can be generated. Thereby, compared with the case where local heating is not performed, the difference in stress applied to each of the first magnetic recording unit and the second magnetic recording unit can be increased, so that the second magnetic recording unit can be compared with the second magnetic recording unit. The effect of preventing erroneous recording can be further increased.

  As described above, the magnetic recording medium according to the present invention is a magnetic recording medium including a magnetic layer to which magnetism is applied on a substrate, and the magnetic layer is compared with a direction parallel to the film surface of the magnetic layer. A plurality of magnetic recording parts, each of which is recorded with information by the applied magnetism, and a film surface of the magnetic layer. A first stress applying portion made of a magnetic material having a relatively large magnetic anisotropy in a direction parallel to the film surface of the magnetic layer as compared with a direction perpendicular to the magnetic layer, and at least a track on which information is recorded The plurality of magnetic recording units and the first stress applying unit are alternately arranged, and the magnetostriction constants of the magnetic recording unit and the first stress applying unit are positive. is there.

  Therefore, it is possible to provide a magnetic recording medium capable of recording high-density magnetic information and preventing erroneous recording of magnetic information.

[Embodiment 1]
One embodiment of the present invention is described below with reference to FIGS. 1 to 9A and 9B.

  First, the configuration of a magnetic recording medium 1 according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 2 is a plan view showing the configuration of the magnetic recording medium 1 according to the embodiment of the invention. FIG. 1 is a cross-sectional view taken along line A-A ′ shown in FIG. 2.

  As shown in FIG. 1, the magnetic recording medium 1 according to the present embodiment includes a magnetic layer 30 to which magnetism is applied on a substrate 2. The magnetic layer 30 is made of a magnetic material that has a relatively large magnetic anisotropy in the direction perpendicular to the film surface of the magnetic layer 30 as compared to the direction parallel to the film surface of the magnetic layer 30. The first magnetic recording unit 3 is formed of a magnetic material having a relatively large magnetic anisotropy in the direction parallel to the film surface of the magnetic layer 30 compared to the direction perpendicular to the film surface of the magnetic layer 30. And a stress applying portion 4. A plurality of magnetic recording units 3 and first stress applying units 4 are alternately arranged along at least a track on which information is recorded. The magnetostriction constants of the magnetic recording unit 3 and the first stress applying unit 4 are positive. The materials of the magnetic recording unit 3 and the first stress applying unit 4 will be described later. Recording magnetic information on the magnetic recording unit 3 is referred to as magnetic recording.

  Here, the direction in which magnetic information is recorded in each of the plurality of magnetic recording units 3, that is, the magnetic recording direction, is the left side direction of the paper as shown by the arrow in FIG.

  As shown in FIG. 1, each of the plurality of magnetic recording units 3 is formed as a region juxtaposed along the surface of the substrate 2. As shown in FIG. 2, the magnetic recording unit 3 is formed as a closed region that is separated from each other and is planar. As shown in FIGS. 1 and 2, in the present embodiment, the magnetic recording unit 3 is formed in a cylindrical shape. The side surface in the direction perpendicular to the film surface of the magnetic recording unit 3 is surrounded by the first stress applying unit 4. Each of the plurality of magnetic recording units 3 is a recording magnetic domain at the time of recording magnetic information. Thereby, even if magnetic information is recorded in a certain magnetic recording unit 3, the magnetic information recorded in the adjacent magnetic recording unit 3 is not affected.

  Further, as shown in FIG. 1, a soft magnetic layer 5 is formed between the magnetic layer 30 and the substrate 2. That is, the soft magnetic layer 5 is formed on the substrate 2, and the magnetic recording portion 3 and the first stress applying portion 4 are alternately and repeatedly formed on the soft magnetic layer 5 in a direction parallel to the film surface. . The magnetic recording medium 1 is a patterned medium in which a protective layer 6 and, if necessary, a lubricating layer 7 are formed by laminating the magnetic recording unit 3 and the first stress applying unit 4.

As the substrate 2, a metal substrate, an oxide substrate, a nitride substrate, a resin substrate, or the like can be used. For example, a SiO ₂ substrate, a glass substrate, or a polycarbonate substrate can be used. Further, a semiconductor substrate may be used.

  The magnetic recording unit 3 is made of a magnetic material having a strong axis of magnetization stronger in the direction perpendicular to the film surface than the parallel direction and having a positive magnetostriction constant.

  The first stress applying part 4 is made of a magnetic material having a strong axis of magnetization stronger in a direction parallel to the direction perpendicular to the film surface and having a positive magnetostriction constant.

  Further, it is desirable that the magnetic body of the magnetic recording unit 3 and the first stress applying unit 4 is an amorphous magnetic body. According to this, as compared with the case where a crystalline metal material is used for the magnetic body, the individual magnetic recording sections 3 in the magnetic recording medium 1 or the like due to lattice defects or unintentional changes in crystal orientation in the recording magnetic domain. Since each magnetic recording unit 3 and the first stress applying unit 4 exhibit the same magnetic characteristics without causing the magnetic characteristic dispersion of the first stress applying unit 4, the magnetic recording medium 1 having stable performance is provided. It is suitable for doing.

  Here, as the first stress applying portion 4, a material having a strong easy axis in a parallel direction (referred to as an in-plane direction or a track length direction as appropriate) relative to a direction perpendicular to the film surface is used. Even if the gap between the magnetic recording unit 3 and another adjacent magnetic recording unit 3 is filled with a magnetic material, the perpendicular magnetic information recorded in one magnetic recording unit 3 is separated by the exchange coupling force. Therefore, the magnetic recording medium 1 can be formed as a patterned medium.

  The soft magnetic layer 5 is a layer for assisting magnetic recording by enhancing a magnetic field in a direction perpendicular to the film surface when an external magnetic field is applied to the magnetic recording unit 3 to perform magnetic recording, and SUL (soft This is also referred to as an under layer. Further, the soft magnetic layer 5 is also referred to as a backing layer. The soft magnetic layer 5 is formed using, for example, NiFe, NiFeTa, CoZr or a soft magnetic material mainly composed of these. When the soft magnetic layer 5 is formed, a nonmagnetic layer may be further formed between the magnetic recording unit 3 and the first stress applying unit 4 and the soft magnetic layer 5. The soft magnetic layer 5 is not necessarily formed when desired magnetic information can be recorded in the magnetic recording unit 3 without the soft magnetic layer 5.

  The protective layer 6 has a role for protecting the magnetic recording unit 3 and the first stress applying unit 4 made of a magnetic material from physical contact from outside such as a magnetic head, and the magnetic recording unit 3 and the first stress applying unit 4. It also serves as an antioxidant layer that prevents oxidative degradation of the stress applying portion 4. The protective layer 6 may be a DLC (diamond-like carbon) film, a nitride film such as AlN, SiN, or CN.

  The lubrication layer 7 is for preventing the magnetic recording medium 1 or the magnetic head from being damaged due to physical contact from the outside such as a magnetic head. For example, a molecular film having a perfluoropolyether skeleton is used. can do.

  Next, the reason why the magnetic recording medium 1 of the present embodiment can prevent erroneous recording with respect to adjacent magnetic domains when magnetic recording is performed will be described with reference to FIG.

  FIG. 3 shows the magnetic recording medium 1 according to the present embodiment and the magnetic recording head 40, and is an explanatory diagram showing the state of the magnetic field when performing magnetic recording. In the schematic diagram of the magnetic recording medium 1 shown in FIG. 3, the protective layer 6 and the lubricating layer 7 are omitted.

  Here, in this embodiment, a perpendicular magnetic recording head as shown in FIG. 3 is used as the magnetic recording head 40 for performing magnetic recording on the magnetic recording medium 1.

  The magnetic recording head 40 is a single magnetic pole head including a main magnetic pole 41 and a trailing shield 42. Although not shown, the magnetic recording head 40 includes a coil for passing a current when recording on the magnetic recording unit 3. In the following description, a perpendicular magnetic head including such a main magnetic pole and a trailing shield may be referred to as a trailing shield type single magnetic pole head.

  The main magnetic pole 41 and the trailing shield 42 are provided adjacent to each other. Then, a magnetic field is applied from the main magnetic pole 41 to the magnetic recording unit 3 and the stress applying unit 4. Then, a part of the applied magnetic field is absorbed by the trailing shield 42.

  Here, in FIG. 3, the magnetic recording direction is the direction from the side where the trailing shield 42 is provided to the side where the main magnetic pole 41 is provided. That is, it is the left direction of the page. This magnetic recording is recorded as the magnetic recording medium 1 moves relative to the magnetic recording head 40. The direction in which the magnetic recording medium 1 moves relative to the magnetic recording head 40 (medium moving direction) is the direction from the side on which the main magnetic pole 41 is provided to the side on which the trailing shield 42 is provided. That is, it is the direction of the arrow shown in FIG.

  When a magnetic field is applied from the main magnetic pole 41 and magnetic information in the direction perpendicular to the film surface (perpendicular magnetic information) is recorded on the magnetic recording unit 3, a strong vertical magnetic field is applied to the magnetic recording unit 3 near the main magnetic pole 41. The

  Both the magnetic recording unit 3a and the magnetic recording unit 3b shown in FIG. 3 are tracks on which magnetic information is recorded. The magnetic recording unit 3 that is located closest to the magnetic field application surface of the main magnetic pole 41 and that wants to perform magnetic recording is defined as a magnetic recording unit 3a. The next magnetic recording unit 3 arranged via the stress applying unit 4 and having already recorded magnetic information is referred to as a magnetic recording unit 3b. In other words, the magnetic recording unit 3 b is a magnetic recording unit 3 that is arranged next to the magnetic recording unit 3 a via the stress applying unit 4 and is located on the side where the trailing shield 42 is formed.

  In addition, the stress applying unit 4 that is disposed between the magnetic recording unit 3a and the magnetic recording unit 3b in the stress applying unit 4 is referred to as a stress applying unit 4a. That is, the first stress applying unit 4 a is the first stress applying unit 4 located closest to the magnetic field application surface of the main magnetic pole 41. And it is the next 1st stress provision part 4 arrange | positioned through the magnetic recording part 3b, Comprising: It arrange | positions adjacent to the magnetic recording part 3b, and sandwiches the magnetic recording part 3b with the 1st stress provision part 4a. The first stress applying part 4 formed at the position is defined as a first stress applying part 4b. That is, the stress applying part 4b is the stress applying part 4 that is disposed adjacent to the stress applying part 4a via the magnetic recording part 3b and is located on the side where the trailing shield 42 is formed.

  Here, the magnetic recording head 40, which is a trailing shield type single magnetic pole head, includes a trailing shield 42 and a main magnetic pole 41 in order to sharpen the magnetic field distribution and increase the magnetic field gradient. The gap length between the trailing shield 42 and the main magnetic pole 41 is reduced. Therefore, in the case of the trailing shield type single magnetic pole head, the gap length between the trailing shield 42 and the main magnetic pole 41 is small, so that a part of the magnetic flux does not reach the soft magnetic layer 5 that is the backing layer from the main magnetic pole 41. , It is often absorbed by the trailing shield 42.

  Therefore, the magnetic recording head 40, which is a trailing shield type single magnetic pole head, not only applies a magnetic field to the magnetic recording portion 3a in the vicinity of the main magnetic pole 41 in the direction perpendicular to the film surface, but also in the direction parallel to the film surface. A magnetic field including a magnetic field component is applied to the magnetic recording unit 3 b in the vicinity of the main magnetic pole 41 that is shifted in the direction of the trailing shield 42. It is also described in Non-Patent Document 1 that a magnetic field component is generated in the in-plane direction in the trailing shield type single magnetic pole head. The 58th and 4th lines indicate that the recording magnetic field is inclined in the in-plane direction from the vertical direction. The state of the magnetic flux from such a trailing shield type single magnetic pole head is schematically shown in FIG. 3 for a cross section in a direction perpendicular to the film surface of the magnetic recording medium 1.

  As shown by the magnetic flux from the main magnetic pole 41 in FIG. 3, perpendicular magnetism, which is magnetism having a strong magnetic field component in the direction perpendicular to the film surface, is applied to the magnetic recording unit 3a. Thereby, magnetic recording is performed on the magnetic recording unit 3a. The perpendicular magnetism applied to magnetically record information on the magnetic recording unit 3a is magnetism having a strong magnetic field component perpendicular to the film surface to the extent that information is magnetically recorded. A magnetic field component in a direction parallel to the surface may be included.

  The magnetic recording unit 3b located at a position shifted from the magnetic recording unit 3a in the magnetic recording direction, that is, the direction in which the trailing shield 42 is positioned, is compared with the magnetic recording unit 3a in the direction parallel to the film surface. A magnetic field containing a lot of magnetic field components is applied. Further, a magnetic field including a component in a direction parallel to the film surface as shown by the magnetic flux from the main magnetic pole 41 in FIG. 3 is applied to the first stress applying portions 4a and 4b sandwiching the magnetic recording portion 3b. Is done. At this time, with respect to the first stress applying portion 4a sandwiched between the magnetic recording portion 3a and the magnetic recording portion 3b to be subjected to magnetic recording, the magnetic recording portion 3b is closer than the vicinity of the boundary surface with the magnetic recording portion 3a. A leakage magnetic field having a component in the direction parallel to the film surface is more strongly applied in the vicinity of the boundary surface between the two. Since the first stress applying portions 4a and 4b have a relatively strong magnetic anisotropy in the parallel direction and a positive magnetostriction constant relative to the direction perpendicular to the film surface, the first stress applying portions 4a and 4b are parallel to the film surface. When a leakage magnetic field containing a large amount of the magnetic field component is applied, magnetostriction that tends to extend in a direction parallel to the film surface is generated.

  Here, generation of magnetostriction will be described. When an external magnetic field is not applied to the magnetic material, the magnetization inside the magnetic material is dispersed to some extent centered on the magnetization direction of the entire magnetic material (a state in which the magnetic material has a dispersion of strain) ).

  On the other hand, by applying a magnetic field from the outside, the magnetization directions inside the magnetic body are aligned (relaxation of strain dispersion), and the outer shape of the entire magnetic body is deformed.

  That is, a magnetic field having a component in a direction parallel to the film surface is applied to the first stress applying portions 4a and 4b having magnetic anisotropy in a direction parallel to the film surface, so that Magnetization extends in the parallel direction, and the magnetizations of the materials in the first stress applying portions 4a and 4b having a positive magnetostriction constant are all increased, thereby generating an expansion strain in the magnetization direction. On the other hand, in the case of a material having a negative magnetostriction constant, a reduction strain occurs in the magnetization direction.

  In particular, since the rare earth element has a large strain, a ferromagnetic compound containing such an element exhibits a large magnetostriction, and the magnetic anisotropy changes greatly accordingly.

  As described above, in the first stress applying portion 4a, the vicinity of the boundary surface with the magnetic recording portion 3b adjacent to the side where the trailing shield 42 is formed is more than the vicinity of the boundary surface with the magnetic recording portion 3a. A leakage magnetic field containing a large amount of magnetic field components parallel to the film surface is strongly applied. For this reason, in the first stress applying portion 4a, the magnetostriction in the direction parallel to the film surface is larger in the vicinity of the boundary surface with the magnetic recording portion 3b than in the vicinity of the boundary surface with the magnetic recording portion 3a.

  Accordingly, the magnetic recording unit 3b positioned in front of the medium moving direction, that is, the track length direction with respect to the magnetic recording unit 3a to perform magnetic recording, and the first stress applying units 4a and 4b sandwiching the magnetic recording unit 3b. , A compressive stress in a direction parallel to the film surface is generated as indicated by an arrow. Then, the magnetic anisotropy (perpendicular magnetic anisotropy) in the direction perpendicular to the film surface of the magnetic recording portion 3b sandwiched between the first stress applying portions 4a and 4b is improved by the inverse magnetostriction effect.

The expression of the inverse magnetostrictive effect is described in detail. When the stress in the direction parallel to the film surface (in-plane stress) σ improves the perpendicular magnetic anisotropy of the magnetic material by the inverse magnetostrictive effect, the induced perpendicular magnetostriction is induced. The isotropic energy density ΔK _u can be expressed by the following equation (1).
ΔK _u = −3 / 2λσ Expression (1)
Here, λ and σ are shown below.
λ: magnetostriction constant of the magnetic material σ: in-plane stress applied to the magnetic material (compression stress: σ <0, elongation stress: σ> 0)
In the magnetic recording medium 1 of the present embodiment, the magnetostriction constant λ is a positive magnetostriction constant of the magnetic recording unit 3, and the medium moving direction, that is, the track length direction with respect to the magnetic recording unit 3a to be magnetically recorded. Compressive stress σ (<0) in the direction parallel to the film surface as indicated by arrows at the boundary surfaces between the magnetic recording unit 3b located in front of the first recording medium and the first stress applying units 4a and 4b sandwiching the magnetic recording unit 3b. ) Occurs. In this case, as indicated by the equation (1), the perpendicular magnetic anisotropy energy density ΔK _{u of} the magnetic recording portion 3b sandwiched between the first stress applying portions 4a and 4b is improved.

Thus, by improving the perpendicular magnetic anisotropy energy density ΔK _u of the magnetic recording unit 3b, even if a leakage magnetic field is applied to the magnetic recording unit 3b, the magnetic information recorded in the magnetic recording unit 3b is changed. It is possible to prevent the influence.

  In the magnetic recording medium 1 of the present embodiment, the magnetic material of the magnetic recording unit 3 is a rare earth metal selected from Gd, Ho, Tb, and Dy and at least one 3d transition metal selected from Fe and Co. It is preferable to comprise.

  According to this, a ferrimagnetic material in which the magnetizations of the rare earth metal and the 3d transition metal are aligned in antiparallel is obtained, and the magnetic recording unit 3 having a positive magnetostriction constant having a large absolute value can be obtained at room temperature. Therefore, the amount of change in perpendicular magnetic anisotropy energy density that appears when in-plane stress is applied to the magnetic recording unit 3 can be increased.

  In addition, by adjusting the alloy composition of the magnetic recording unit 3 and setting a compensation point near room temperature, a high coercive force can be obtained at room temperature, so that recording information can be stably maintained and the Curie temperature can be set relatively low. A magnetic recording medium 1 having a magnetic recording unit 3 suitable for heat-assisted magnetic recording can be provided. Furthermore, since an alloy of Tb, Fe, and Co can obtain high perpendicular magnetic anisotropy energy, it is suitable for use as the magnetic recording portion 3 of the magnetic recording medium 1 according to the present embodiment. At this time, by using an alloy of Tb, Fe, and Co having strong perpendicular magnetic anisotropy for the magnetic recording portion 3, the magnetization of the magnetic recording portion 3 is magnetically different in the direction parallel to the film surface by the first stress applying portion 4. It is possible to prevent tilting from the direction perpendicular to the film surface under the influence of the directionality.

  Furthermore, in the magnetic recording medium 1 of the present embodiment, the magnetic material of the first stress applying unit 4 is at least one selected from Gd, Ho, Tb, Dy and Fe, Co. Preferably, it comprises two 3d transition metals.

  According to this, the first stress applying part 4 having a large absolute value and a positive magnetostriction constant at room temperature can be obtained. In addition, when the alloy composition of the first stress applying portion 4 is adjusted so that the magnetic anisotropy in the direction parallel to the film surface is relatively stronger than in the vertical direction, and a magnetic field in the direction parallel to the film surface is applied And the coercive force when a magnetic field is applied in the direction perpendicular to the film surface is set large. As a result, when a magnetic field having a component parallel to the film surface is applied to the first stress applying unit 4, the first stress applying unit 4 generates magnetostriction in the direction parallel to the film surface, A compressive stress in a direction parallel to the film surface is applied to the magnetic recording portion 3b adjacent to the stress applying portion 4. For this reason, the perpendicular magnetic anisotropy of the magnetic recording part 3b adjacent to the first stress applying part 4 is improved by the inverse magnetostriction effect.

  Moreover, as a magnetic material of the 1st stress provision part 4, TbFe, (TbDy) Fe Laves phase terphenol alloy, TbHoFe etc. can be used, for example. Among them, the thin film alloy of Tb and Fe has a large positive magnetostriction constant, and is suitable for use as the first stress applying portion 4 of the magnetic recording medium 1 according to the present embodiment. The thin film composition of TbFe is preferably formed so that the amount of Tb is 45 to 50 at%. As described in Non-Patent Document 3, this has perpendicular magnetic anisotropy when the amount of Tb is about 20 to 40%, and the first stress applying unit 4 according to the present embodiment includes It is not suitable. Further, since the value of the saturation magnetostriction rapidly decreases when the amount of Tb is 50% or more, it is desirable that the TbFe composition used as the first stress applying portion 4 is formed so that the amount of Tb is 45 to 50%.

Further, it is generally known that in a magnetic body made of a rare earth-transition metal alloy, the coercive force is improved as the perpendicular magnetic anisotropy energy density is improved by the inverse magnetostrictive effect. As the perpendicular magnetic anisotropy energy density of the magnetic recording unit 3b according to the present embodiment increases, the coercive force H of the magnetic recording unit 3b when a magnetic field is applied to the magnetic recording unit 3b in the direction perpendicular to the film surface. _{Since c} is improved, it is possible to prevent erroneous recording of perpendicular magnetic recording with respect to the magnetic recording unit 3b.

  Next, a method for manufacturing the magnetic recording medium 1 according to this embodiment will be described as follows with reference to FIGS. 4 (a), 4 (b) to 6 (a), (b).

  4A shows a manufacturing process of the magnetic recording medium 1 according to the present embodiment, and is a cross-sectional view in which the soft magnetic layer 5, the first stress applying portion 4, and the resist 8 are stacked on the substrate 2. FIG. FIG. 4B shows a cross-sectional view when the resist 8 in FIG. 4A is patterned.

  FIG. 5A is a cross-sectional view showing a case where the first stress applying portion 4 of the magnetic recording medium 1 in FIG. 4A is patterned, and FIG. 5B is a diagram in FIG. A sectional view in the case of forming the magnetic recording unit 3 is shown.

  6A is a cross-sectional view when the resist 8 of the magnetic recording medium 1 shown in FIG. 5B is removed. FIG. 6B shows a protective layer on the magnetic recording medium 1 of FIG. 6 and a cross-sectional view when the lubricating layer 7 is formed are shown.

  First, as shown in FIG. 4A, a soft magnetic layer 5 having a thickness of, for example, about 100 nm to 400 nm and a first stress applying portion 4 having a thickness of about 10 nm to 100 nm are stacked on the substrate 2. Thus, a resist 8 film having a thickness of about 100 nm to 400 nm is formed. Thereafter, a fine pattern corresponding to the magnetic recording portion 3 and the first stress applying portion 4 shown in FIG. 2 is exposed using electron beam lithography or optical lithography. Then, development is performed to remove the exposed resist 8, and an island of the resist 8 is formed on the first stress applying portion 4 as shown in FIG.

  Next, as shown in FIG. 5A, for example, RIE (Reactive Ion Etching) is used by using, as a mask, a fine pattern of a portion corresponding to the first stress applying portion 4 manufactured in the process of forming the resist 8. The first stress applying portion 4 is processed to form a concave groove. At this time, due to the difference in the etching rate between the first stress applying portion 4 and the resist 8, the portion where the resist 8 remains on the first stress applying portion 4 is not processed, but on the first stress applying portion 4. The portion where the resist 8 does not remain is etched. As the gas to be used when performing the RIE, methanol gas or CO-containing gas capable of etching the magnetic body constituting the first stress applying unit 4 at a high rate is desirable. However, it is not limited to the above gas types, and other gases may be used as long as the first stress applying part 4 can be etched. Further, Ar ion milling may be used instead of RIE. At this time, etching is performed to a depth at which the outermost surface of the soft magnetic layer 5 appears.

  Next, as shown in FIG. 5B, the magnetic recording unit 3 is formed on the soft magnetic layer 5. At this time, the film thickness of the magnetic recording unit 3 is made the same as that of the first stress applying unit 4. Although not shown in the figure, it is desirable to form a nonmagnetic film with a thickness of, for example, about 1 nm to 10 nm after the magnetic recording unit 3 is formed to prevent oxidation of the magnetic recording unit 3.

  Next, as shown in FIG. 6A, the resist 8 remaining on the first stress applying portion 4 is removed by using a stripping solution, so that the magnetic recording portion 3 laminated on the resist is also removed at the same time. It is. Thereby, the shape without an unevenness | corrugation on the surface of the magnetic-recording part 3 and the 1st stress provision part 4 can be obtained.

Finally, as shown in FIG. 6B, a protective layer 6 for preventing oxidation of the magnetic recording portion 3 and the first stress applying portion 4 and a lubricating layer 7 for stable floating of the magnetic recording head 40. Form.
Through the above steps, the magnetic recording medium 1 of the present embodiment is completed.

Example 1
Next, examples of manufacturing the magnetic recording medium 1 shown in the first embodiment will be described below.

First, a soft magnetic layer 5 made of NiFe is formed by sputtering on a substrate 2 made of SiO _{2 so as} to have a thickness of 150 nm, and a first stress applying portion 4 made of Tb ₄₆ Fe _{54 is formed} on the soft magnetic layer 5. Sputter film formation is carried out so that it may become 80 nm. Here, the magnetic properties of Tb ₄₆ Fe ₅₄ used as the first stress applying portion 4 have a relatively strong magnetic anisotropy in the parallel direction to the direction perpendicular to the film surface, and in the direction parallel to the film surface. The coercive force when a magnetic field was applied was about 100 Oe. At this time, the sputtering apparatus used for sputtering film formation was a sputtering apparatus of a type in which the target and the substrate holder face each other and the substrate holder revolves and revolves. Furthermore, after applying a resist 8 for electron beam to a thickness of 300 nm, the resist 8 was exposed and developed by electron beam lithography.

Subsequently, by using RIE (Reactive Ion Etching), the first stress applying part 4 is processed with CF ₄ gas, and the first stress applying part 4 and the unevenness of the resist 8 as shown in FIG. A shape was formed.

Next, the magnetic recording part 3 made of TbFeCo is formed by sputtering with a film thickness of 80 nm on the resist 8 and between the first stress applying parts 4 and 4 and on the soft magnetic layer 5 (FIG. 5B). The resist 8 was peeled off (FIG. 6A). Here, TbFeCo used as the magnetic recording part 3 was produced with a TM rich composition such that the compensation temperature was not more than room temperature. The magnetic characteristics of the magnetic recording unit 3 have a relatively strong magnetic anisotropy in the direction perpendicular to the direction parallel to the film surface, and the coercivity H _c at room temperature when a magnetic field is applied in the direction perpendicular to the film surface. Was 6 kOe and the Curie temperature _Tc was 290 ° C. Further, _Ku was 7.0 × 10 ⁶ [erg / cm ³ ].

  Finally, 2 nm of AlN and 2 nm of diamond like carbon (DLC) were formed as the protective layer 6, respectively, and then the lubricating layer 7 was applied to complete the magnetic recording medium 1 (FIG. 6B). At this time, the diameter of the magnetic recording portion 3 was 60 nm, and the minimum width of the first stress applying portion 4 was 40 nm.

Here, the perpendicular magnetic anisotropy energy density ΔK _u of the magnetic recording portion 3 b induced by the inverse magnetostriction effect at the time of recording the magnetization information of the magnetic recording medium 1 of the present embodiment was calculated using the formula (1). . The in-plane stress σ in equation (1) can be expressed by the following equation (2).
σ = Eε Formula (2)
Here, E and ε are shown below.
E: Young's modulus ε: strain In the calculation, the diameter of the magnetic recording portion 3 was set to 60 nm, and the minimum width of the first stress applying portion 4 was set to 40 nm. From Patent Document 1, the magnetostriction constant of TbFeCo used in the magnetic recording unit 3 is set to 1000 × 10 ⁻⁶ and the Young's modulus E is set to 7 × 10 ¹¹ [dyn / cm ² ]. Further, from FIG. 1 of Non-Patent Document 3, the calculation was performed with the magnetostriction constant of TbFe used for the first stress applying portion 4 being 200 × 10 ⁻⁶ .

When ΔK _u was calculated by applying the above constants to Equation (1), ΔK _u = 2.8 × 10 ⁵ [erg / cm ³ ] was obtained. This is because, when a magnetic field in a direction parallel to the film surface is applied to the magnetic recording medium 1, stress acts on the magnetic recording unit 3 by the first stress applying unit 4, and the perpendicular magnetic anisotropy of the magnetic recording unit 3. It shows that the energy density is increased by about 2.8 × 10 ⁵ [erg / cm ³ ].

  Next, using the magnetic recording medium 1 and the comparative example 1, magnetic recording was performed using the magnetic recording head 40 shown in FIG. 3 which is the same trailing single-pole head, and then MFM was used. Then, the magnetization reversal of the magnetic domain was observed.

  FIG. 7 is a cross-sectional view showing a configuration of a magnetic recording medium 21 as a comparative example. As shown in FIG. 7, the magnetic recording medium 21 is formed with a nonmagnetic portion 9 made of a nonmagnetic material instead of the first stress applying portion 4 of the magnetic recording medium 1.

  Here, the size of the magnetic recording head 40 for performing magnetic recording is such that the width of the main pole 41 in the track length direction is 100 nm, the width of the main pole 41 in the track width direction is 100 nm, and the gap between the main pole 41 and the trailing shield 42. A length of 50 nm was used. In this embodiment, the current passed through the coil of the magnetic recording head 40 during recording is 45 mA.

  Next, a magnetic recording method for the magnetic recording medium 1 according to the present embodiment and the magnetic recording medium 21 according to the comparative example 1 will be described with reference to FIGS.

  FIG. 8A is a schematic view of the magnetic recording medium 1 according to the present embodiment and the magnetic recording medium 21 according to the comparative example, and a cross-sectional view illustrating a case where the magnetization directions of the magnetic recording unit 3 are the same direction. FIG. 8B is a cross-sectional view showing a case where the magnetization directions of the magnetic recording unit 3 in FIG. 8A are different. In the magnetic recording medium 1 and the magnetic recording medium 21 in FIG. 8, the substrate 2, the soft magnetic layer 5, the protective layer 6, and the lubricating layer 7 are omitted. Further, the medium moving direction is rightward as shown by the arrow. The arrows in the magnetic recording units 3, 3d, and 3c indicate the magnetization directions of the recorded magnetic domains.

  First, as shown in FIG. 8A, the magnetization directions of all the magnetic recording portions 3 of the magnetic recording medium 1 of Example 1 and the magnetic recording medium 21 of Comparative Example 1 were set upward in the same direction. Next, as shown in FIG. 8B, in each of the magnetic recording medium 1 of Example 1 and the magnetic recording medium 21 of Comparative Example 1, a downward pulse magnetic field was applied only to one magnetic recording unit 3d. . After applying the magnetic field, MFM observation of the magnetic recording part 3d to which the magnetic recording medium 1 of Example 1 and the magnetic recording medium 21 of Comparative Example 1 were applied was conducted. As a result, the magnetic recording medium 1 of Example 1 was magnetic. It was observed that one magnetic recording unit 3 having a diameter of 60 nm considered to correspond to the recording unit 3d was reversed in magnetization. On the other hand, in the magnetic recording medium 21 of Comparative Example 1, it was observed that two 60 nm diameter magnetic recording units 3 considered to correspond to the magnetic recording unit 3d and the magnetic recording unit 3c were reversed in magnetization.

  As described above, the reason why different magnetization reversal states are observed in the magnetic recording medium 1 of Example 1 and the magnetic recording medium 21 of Comparative Example 1 even when magnetic recording is performed using the same recording method. This will be described with reference to FIGS.

  Consider a case in which a downward pulsed magnetic field is applied only to the magnetic recording unit 3d in the magnetic recording medium 1 of Example 1 and the magnetic recording medium 21 of Comparative Example 1. At this time, as shown in FIG. 8A, in the first embodiment, only the magnetic recording portion 3d is magnetically recorded downward. On the other hand, in the magnetic recording medium 21, downward magnetic recording is performed on the magnetic recording unit 3 d, and in the magnetic recording direction of the magnetic recording unit 3 d, that is, in the direction of the trailing shield 42 due to the leakage magnetic field from the magnetic recording head 40. It is considered that magnetic recording was also performed on the adjacent magnetic recording portion 3c.

  That is, when the magnetic recording medium 1 of this embodiment records a magnetic field perpendicular to the film surface (perpendicular magnetic information) on the magnetic recording unit 3e by applying a magnetic field, the leakage has a component parallel to the film surface. A magnetic field is applied to the first stress applying unit 4. Then, in the first stress applying portion 4 of the magnetic recording medium 1, magnetostriction in the direction parallel to the film surface is generated, and the magnetic recording portion 3c positioned ahead in the track length direction from the magnetic recording portion 3d to be magnetically recorded. Compressive stress in the direction parallel to the film surface is generated. Thereby, the perpendicular magnetic anisotropy of the magnetic recording portion 3c sandwiched between the first stress applying portions 4 is improved by the inverse magnetostriction effect, and erroneous recording on the magnetic recording portion 3c can be prevented.

  In contrast, the magnetic recording medium 21 of Comparative Example 1 does not include the first stress applying unit 4 for improving the perpendicular magnetic anisotropy of the magnetic recording unit 3c adjacent to the magnetic recording unit 3d. The perpendicular magnetic anisotropy of the recording unit 3c was not improved by the inverse magnetostriction effect, and erroneous recording on the magnetic recording unit 3c could not be prevented.

  Further, the magnetic recording medium 1 according to the present embodiment may have a configuration shown in FIGS. FIG. 9A shows a modification of the magnetic recording medium 1 according to the present embodiment, in which a nonmagnetic portion 9 is formed between the magnetic recording portion 3 and the first stress applying portion 4. FIG. 9B is a cross-sectional view illustrating the configuration of the medium 50, and FIG. 9B illustrates a modification of the magnetic recording medium 1 according to the present embodiment, occupying gaps between the plurality of magnetic recording units 3, and the first 6 is a cross-sectional view illustrating a configuration of a magnetic recording medium 55 in which a nonmagnetic portion 9 is formed in a film thickness direction of a stress applying portion 4. FIG.

  As shown in FIG. 9A, in the magnetic recording medium 50, a nonmagnetic portion 9 made of a nonmagnetic material is formed between the magnetic recording portion 3 and the first stress applying portion 4.

  According to this, since the magnetic coupling between the magnetic recording unit 3 and the first stress applying unit 4 adjacent thereto is broken, the magnetization component in the parallel direction in the first stress applying unit 4 is caused by the perpendicular magnetization of the magnetic recording unit 3. There is no weakening. Further, the magnetostriction in the direction parallel to the film surface of the first stress applying portion 4 at the time of applying the magnetic field is not reduced. That is, since the perpendicular magnetic anisotropy of the magnetic recording unit 3b can be stably improved by the inverse magnetostriction effect, erroneous recording on the magnetic recording unit 3b can be prevented. Further, since the magnetic coupling between the magnetic recording unit 3 and the first stress applying unit 4 adjacent to the magnetic recording unit 3 is broken, the magnetic recording unit 3 is balanced by the magnetic anisotropy in the in-plane direction of the first stress applying unit 4. It is possible to prevent the magnetization direction from tilting from the perpendicular direction and to maintain the recording magnetic domain stably. That is, stable magnetic recording can be performed.

  In the present embodiment, as shown in FIG. 9B, the first stress applying portion 4 of the magnetic recording medium 55 has a length (height) in the direction perpendicular to the film surface as compared with the magnetic recording portion 3. A) is formed short. A nonmagnetic portion 9 is formed on the first stress applying portion 4. The total height of the first stress applying portion 4 and the nonmagnetic portion 9 and the height of the magnetic recording portion 3 are formed to be the same. That is, the nonmagnetic portion 9 occupies the gaps between the plurality of magnetic recording portions 3 and is formed in the film thickness direction of the first stress applying portion 4.

  According to this, compared with the magnetic recording medium 1 which does not form the nonmagnetic part 9 shown in FIG. 1, the thickness of the 1st stress provision part 4 can be made thin. Here, as described above, the first stress applying portion 4 is made of a magnetic material having a relatively large magnetic anisotropy in the direction parallel to the film surface as compared to the direction perpendicular to the film surface. For this reason, the direction in which the first stress applying portion 4 has magnetization in the direction parallel to the film surface is more stable in terms of energy. Then, by reducing the thickness of the first stress applying portion 4, the magnetic anisotropy in the direction parallel to the film surface can be stabilized by the shape magnetic anisotropy.

  For this reason, the perpendicular magnetic anisotropy of the magnetic recording part 3b sandwiched between the first stress applying parts 4 is improved by the inverse magnetostriction effect, and erroneous recording on the magnetic recording part 3b can be prevented. Furthermore, at the location where the nonmagnetic portion 9 is formed, the magnetic coupling between the magnetic recording portion 3 and another magnetic recording portion 3 adjacent to the magnetic recording portion 3 is cut off. It is possible to prevent the recorded perpendicular magnetic information from being transferred to the adjacent magnetic recording unit 3 by the exchange coupling force.

  In FIG. 9B, the first stress applying portion 4 and the nonmagnetic portion 9 are formed in the order of the first stress applying portion 4 and the nonmagnetic portion 9 when viewed from the substrate 2 side. The stress applying portion 4 and the nonmagnetic portion 9 may be interchanged.

[Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected about the member same as 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 10 is a cross-sectional view of the configuration of the magnetic recording medium 11 according to the present embodiment.

  The first embodiment is different from the second embodiment in that a second stress applying unit 10 having a negative magnetostriction constant is provided in the lower layer of the magnetic recording unit 3.

  As shown in FIG. 10, the magnetic recording medium 11 according to the second embodiment of the present invention includes a second stress applying unit in each of the plurality of magnetic recording units 3 in the film thickness direction of the magnetic recording unit 3. 10 is formed. Here, the second stress applying unit 10 formed in the film thickness direction of the magnetic recording unit 3 only needs to be formed within the film thickness of the magnetic recording unit 3. That is, the second stress applying unit 10 may be formed below the magnetic recording unit 3 (the film surface portion on the side where the substrate 2 is provided), or above the magnetic recording unit 3 (the substrate 2). May be formed in the middle layer portion (portion between the lower portion and the upper portion). In the present embodiment, the second stress applying part 10 is formed in the lower part in the magnetic recording part 3. That is, the second stress applying unit 10 is formed in a layer between the magnetic recording unit 3 and the soft magnetic layer 5. The thickness in the height direction of the magnetic recording portion 3 and the soft magnetic layer 5 is formed so as to be the same as the thickness in the height direction of the first stress applying portion 4. Further, the second stress applying part is surrounded by the first stress applying part on the side surface in the direction perpendicular to the film surface.

  In addition, let the 2nd stress provision part 10 formed in the lower layer of the magnetic-recording part 3a be the 2nd stress provision part 10a. The second stress applying part 10 formed in the lower layer of the magnetic recording part 3b is referred to as a second stress applying part 10b.

  The second stress applying part 10 is made of a magnetic material having a strong axis of magnetization stronger in a direction parallel to the direction perpendicular to the film surface and having a negative magnetostriction constant. The magnetic body of the second stress applying unit 10 is preferably an amorphous magnetic body. According to this, as compared with the case where a crystalline metal material is used for the magnetic material, each second stress application in the magnetic recording medium 11 is caused by lattice defects or an unintentional change in crystal orientation in the recording magnetic domain. The dispersion of the magnetic characteristics of the portion 10 does not occur. For this reason, each of the second stress applying portions 10 exhibits the same magnetic characteristics, which is suitable for providing the magnetic recording medium 11 with stable performance. In FIG. 10, the magnetic recording unit 3 is formed on the second stress applying unit 10 as viewed from the substrate 2 side, but the second stress applying unit 10 and the magnetic recording unit 3 The stacking order may be changed.

  Here, the reason why erroneous recording can be prevented for adjacent magnetic domains when magnetic recording is performed on the magnetic recording medium 11 of the present embodiment will be described with reference to FIG.

  FIG. 11 shows the magnetic recording medium 11 and the magnetic recording head 40 according to the present embodiment, and is an explanatory diagram showing the state of a magnetic field when recording magnetic information. In the schematic diagram of the magnetic recording medium 11 shown in FIG. 11, the protective layer 6 and the lubricating layer 7 are omitted.

  As shown in FIG. 11, the magnetic recording medium 11 in the present embodiment includes a magnetic layer 31 on which magnetic information is recorded on a substrate 2, and the magnetic layer 31 is perpendicular to the film surface. The magnetic anisotropy in the direction parallel to the plurality of magnetic recording units 3 made of a magnetic material having a relatively large magnetic anisotropy compared to the in-plane direction and the film surface that occupies the gap between the magnetic recording units 3 is perpendicular. The first stress applying portion 4 is made of a magnetic material that is relatively larger than the direction. The magnetic recording units 3 are separated from each other, and the cross section in the direction parallel to the film surface is a closed region and is formed as a region juxtaposed along the surface of the substrate 2. Furthermore, the magnetostriction constants of the magnetic recording unit 3 and the first stress applying unit 4 are positive. These configurations are the same as those of the magnetic recording medium 1.

  Further, in the magnetic recording medium 11, a second stress applying portion 10 having a gap in the first stress applying portion 4 and having a negative magnetostriction constant in the film thickness direction of the plurality of magnetic recording portions 3 is formed. It is the composition which is. The second stress applying unit 10 is formed below the magnetic recording unit 3.

  Here, the magnetic recording head 40 shown in FIG. 3 is used as a magnetic recording head for recording information on the magnetic recording medium 11. That is, also in this embodiment, a perpendicular magnetic recording head provided with a main magnetic pole 41 and a trailing shield 42 is used as the magnetic recording head 40. Also in FIG. 11, similar to FIG. 3, the state of the magnetic flux by the magnetic recording head 40 which is a trailing shield type single pole head of the perpendicular magnetic recording head is schematically shown in a cross section perpendicular to the film surface of the magnetic recording medium 11. It shows.

  As shown in FIG. 11, when a perpendicular magnetic information is recorded on the magnetic recording unit 3 by applying a magnetic field from the main magnetic pole 41, a strong perpendicular magnetic field is applied to the magnetic recording unit 3a near the main magnetic pole 41.

  Thus, not only the magnetic field in the vertical direction but also the magnetic recording unit 3b located at a position shifted from the main magnetic pole 41 in the medium moving direction, that is, in the direction of the trailing shield 42, from the magnetic recording unit 3a as shown in FIG. A magnetic field containing components in the direction parallel to and perpendicular to the film surface, as indicated by the magnetic flux from the main magnetic pole 41, is applied. Further, for the first stress applying portions 4a and 4b sandwiching the magnetic recording portion 3b and the second stress applying portion 10b formed in the film thickness direction under the magnetic recording portion 3b, FIG. A magnetic field including a component in a direction parallel to the film surface as indicated by the magnetic flux from the main magnetic pole 41 is applied.

  At this time, with respect to the first stress applying portion 4a sandwiched between the magnetic recording portion 3a and the magnetic recording portion 3b to be subjected to magnetic recording, the magnetic recording portion 3b is closer than the vicinity of the boundary surface with the magnetic recording portion 3a. A leakage magnetic field having a component in a direction parallel to the film surface is more strongly applied in the vicinity of the boundary.

  Since the first stress applying portions 4a and 4b have a relatively strong magnetic anisotropy in the in-plane direction as compared with the direction perpendicular to the film surface and have a positive magnetostriction constant, A magnetostriction that tends to extend in a direction parallel to the film surface is generated by applying the leakage magnetic field having As described above, in the first stress applying portion 4a, a leakage magnetic field having a component parallel to the film surface is more strongly applied near the boundary with the magnetic recording portion 3b than near the boundary with the magnetic recording portion 3a. The magnetostriction in the direction parallel to the film surface is larger in the vicinity of the boundary surface with the magnetic recording portion 3b than in the vicinity of the boundary surface with the magnetic recording portion 3a.

  As a result, at the interface between the magnetic recording unit 3b positioned in front of the medium moving direction with respect to the magnetic recording unit 3a to be magnetically recorded and the first stress applying units 4a and 4b sandwiching the magnetic recording unit 3b, the arrow As shown in FIG. 2, compressive stress in the direction parallel to the film surface is generated.

  Furthermore, as described above, a leakage magnetic field having a component in a direction parallel to the film surface is applied to the first stress applying unit 4, and at the same time, a component in the direction parallel to the film surface is also applied to the second stress applying unit 10b. The leakage magnetic field which has is applied.

  As described above, the second stress applying portion 10b has a relatively strong magnetic anisotropy in the in-plane direction as compared with the direction perpendicular to the film surface and has a negative magnetostriction constant. By applying a leakage magnetic field having a component, magnetostriction that tends to contract in a direction parallel to the film surface is generated.

  At this time, since the magnetic recording portion 3b formed in the film thickness direction of the second stress applying portion 10b is closely stacked with the second stress applying portion 10b, the magnetostriction of the second stress applying portion 10b. The compressive stress in the direction parallel to the film surface as indicated by the arrow acts on the magnetic recording portion 3b by being dragged by the contraction due to.

  Thus, magnetostriction in the direction parallel to the film surface is generated in the first stress applying part 4 and the second stress applying part 10. The compressive stress in the direction parallel to the film surface of the magnetic recording unit 3b positioned in front of the medium moving direction from the magnetic recording unit 3a to be magnetically recorded is higher than that of the magnetic recording medium 1 according to the first embodiment. It will occur more strongly. Therefore, in the magnetic recording medium 11, the perpendicular magnetic anisotropy of the magnetic recording unit 3 b sandwiched between the first stress applying units 4 a and 4 b is further improved by the inverse magnetostriction effect than the magnetic recording medium 1.

Furthermore, with the improvement of the perpendicular magnetic anisotropy energy density of the magnetic recording portion 3b, so improving the coercive force H _c at the time of applying a magnetic field in the direction perpendicular to the film plane of the magnetic recording portion 3b, the magnetic recording portion 3b It becomes possible to prevent erroneous recording of perpendicular magnetic recording.

  In the magnetic recording medium 11 of the present embodiment, the magnetic body of the second stress applying unit 10 is preferably made of SmFe.

  According to this, the second stress applying part 10 having a large absolute value and a negative magnetostriction constant at room temperature can be obtained. Further, the alloy composition of the second stress applying portion 10 is adjusted so that the magnetic anisotropy in the parallel direction to the film surface is relatively stronger than in the vertical direction. Thereby, the coercive force when applying a magnetic field in the direction parallel to the film surface is set to be small, and the coercive force when applying a magnetic field in the direction perpendicular to the film surface is set to be large.

  For this reason, when a magnetic field having a component parallel to the film surface is applied to the second stress applying portion 10b, magnetostriction in the direction parallel to the film surface is generated, and the magnetism adjacent to the second stress applying portion 10b is generated. By applying a compressive stress in a direction parallel to the film surface to the recording unit 3b, the perpendicular magnetic anisotropy of the magnetic recording unit 3b adjacent to the second stress applying unit 10b is improved by the inverse magnetostriction effect, and the magnetic recording unit 3b Incorrect recording can be prevented.

  Here, the thin film composition of SmFe is desirably formed so that the Sm amount is 30 to 40 at%. This is because, as described in Non-Patent Document 3, the SmFe thin film becomes an in-plane magnetization film regardless of the composition, but the absolute value of the magnetostriction constant becomes maximum when the Sm amount is 30 to 40 at%. .

  The manufacturing method of this embodiment uses the same manufacturing method as the manufacturing method using electron beam lithography or optical lithography shown in the first embodiment. The difference is that, in the manufacturing process of the magnetic recording medium 1 of the first embodiment, instead of forming only the magnetic recording part 3, the second stress applying part 10 and the magnetic recording part 3 are formed in the film thickness direction. Only the difference.

(Example 2)
Next, an example of manufacturing the magnetic recording medium 11 shown in the second embodiment is shown below.

First, a soft magnetic layer 5 made of NiFe is formed by sputtering on a substrate 2 made of SiO _{2 so as} to have a thickness of 150 nm, and a first stress applying portion 4 made of Tb ₄₆ Fe _{54 is formed} on the soft magnetic layer 5. Sputter film formation is carried out so that it may become 80 nm. Here, the magnetic properties of Tb ₄₆ Fe ₅₄ used for the first stress applying portion 4 are the same as those in the first embodiment. Further, after applying an electron beam resist 8 to a thickness of 300 nm, the resist 8 was exposed and developed by electron beam lithography.

Subsequently, using RIE (Reactive Ion Etching), the first stress applying portion 4 was processed with CF ₄ gas to form an uneven shape. The shape of the unevenness formed at this time was such that the minimum width of the convex portion was 40 nm, the concave groove depth of the first stress applying portion was 80 nm, and the concave portion diameter was 60 nm.

Subsequently, the second stress applying portion 10 made of Sm ₄₀ Fe ₆₀ was sputtered to a thickness of 20 nm and the magnetic recording portion 3 made of TbFeCo was sputtered to a thickness of 60 nm, and the resist 8 was peeled off. Here, the magnetic properties of Sm ₄₀ Fe ₆₀ used as the second stress applying portion 10 have a stronger magnetic anisotropy in the in-plane direction than in the direction perpendicular to the film surface, and a magnetic field in the in-plane direction. The coercive force when applied was about 100 Oe. The magnetic characteristics of TbFeCo used for the magnetic recording unit 3 are the same as those in the first embodiment.

  Finally, 2 nm of AlN and 2 nm of diamond like carbon (DLC) were formed as the protective layer 6, respectively, and then the lubricating layer 7 was applied to complete the magnetic recording medium 11.

Here, as in Example 1, the perpendicular magnetic anisotropy energy density ΔK _u of the magnetic recording portion 3 b induced by the inverse magnetostriction effect at the time of magnetic information recording of the magnetic recording medium 11 of this example is expressed by the formula ( Calculate using 1). In the calculation, the non-patent document 3 calculated that the magnetostriction constant of SmFe used for the second stress applying unit 10 was −300 × 10 ^−6, and other values were the same as in Example 1. .

When ΔK _u was calculated by applying the above constants to Equation (1), ΔK _u = 6.0 × 10 ⁵ [erg / cm ³ ] was obtained. This is because when the in-plane magnetic field is applied to the magnetic recording medium 11, stress is applied to the magnetic recording unit 3 by the first stress applying unit 4 and the second stress applying unit 10, and the perpendicular to the magnetic recording unit 3. It shows that the magnetic anisotropy energy density is increased by about 6.0 × 10 ⁵ [erg / cm ³ ].

Further, when compared with the induced perpendicular magnetic anisotropy energy density ΔK _{u due} to the inverse magnetostriction effect in the magnetic recording medium 1 of Example 1, the induced perpendicular magneto anisotropy due to the inverse magnetostriction effect in the magnetic recording medium 11 of the present example. The energy density ΔK _u is about twice as large. Therefore, the coercive force H _c at the time of applying a magnetic field in the direction perpendicular to the film plane of the magnetic recording portion 3b, so improved than the magnetic recording medium 1 of Example 1, erroneous perpendicular magnetic information to the magnetic recording portion 3b Recording can be prevented.

  Next, by using the magnetic recording medium 11 of Example 2 and the magnetic recording medium 1 of Example 1 in the same manner as in Example 1, the magnetic recording head 40, which is the same trailing type single pole head, is used. After performing magnetic recording using the MFM, the magnetic domain magnetization reversal was observed using the MFM.

  The size of the magnetic recording head 40 for performing magnetic recording is the same as in the first embodiment. The main magnetic pole 41 has a width in the track length direction of 100 nm, the main magnetic pole 41 has a width in the track width direction of 100 nm, and the main magnetic pole 41 and trailing. A gap with the shield 42 having a gap length of 50 nm was used. The current flowing through the coil of the main magnetic pole 41 when performing magnetic recording was set to 55 mA, which is larger than that in the first embodiment.

  A magnetic recording method will be described with reference to FIGS.

  FIG. 12A schematically shows the magnetic recording medium 11 according to the present embodiment and the magnetic recording medium 1 according to the first embodiment, and shows a case where the magnetization directions of the magnetic recording section 3 are the same direction. FIG. 12B is a cross-sectional view showing a case where the magnetization direction of the magnetic recording unit 3 in FIG. 12A is different. 12A and 12B, the substrate 2, the soft magnetic layer 5, the protective layer 6, and the lubricating layer 7 are omitted. Also, the magnetic recording direction is rightward as shown by the arrow.

  First, as shown in FIG. 12A, the magnetization directions of all the magnetic recording units 3 of the magnetic recording medium 11 of Example 2 and the magnetic recording medium 1 of Example 1 were set upward in the same direction. An arrow in the magnetic recording unit 3 indicates the magnetization direction of the recorded magnetic domain.

  Next, in each of the magnetic recording medium 11 of Example 2 and the magnetic recording medium 1 of Example 1, a downward pulse magnetic field was applied only to the magnetic recording unit 3d. After applying the magnetic field, MFM observation of the magnetic recording part 3d to which the magnetic recording medium 11 and the magnetic recording medium 1 were applied, respectively, revealed that the magnetic recording medium 1 corresponds to the magnetic recording part 3d adjacent to the magnetic recording part 3c. Then, it was observed that the two magnetic recording portions 3 having a diameter of 60 nm considered to be reversed in magnetization. On the other hand, in the magnetic recording medium 11, it was observed that only one 60 nm diameter magnetic recording unit 3 considered to correspond to the magnetic recording unit 3d was reversed in magnetization.

  Thus, the reason why different magnetization reversals are observed even when recording is performed using the same recording method in the magnetic recording medium 11 of Example 2 and the magnetic recording medium 1 of Example 1. This will be described in detail with reference to FIG.

  Consider a case where a downward pulse magnetic field is applied only to the magnetic recording portion 3d in the magnetic recording medium 11 of the second embodiment and the magnetic recording medium 1 of the first embodiment. At this time, as shown in FIG. 12B, in the magnetic recording medium 11, only the magnetic recording portion 3d is magnetically recorded downward. On the other hand, in the magnetic recording medium 1, downward magnetic recording is performed on the magnetic recording unit 3 d, and in the medium moving direction of the magnetic recording unit 3 d, that is, in the direction of the trailing shield 42 due to the leakage magnetic field from the magnetic recording head 40. It is considered that magnetic recording was also performed on the adjacent magnetic recording portion 3c.

  That is, in the magnetic recording medium 11 of this embodiment, when a perpendicular magnetic information is recorded on the magnetic recording unit 3 by applying a magnetic field, a leakage magnetic field having a component in a direction parallel to the film surface is different from that of the first stress applying unit 4. Applied to the second stress applying unit 10. Then, magnetostriction in the direction parallel to the film surface is generated in the first stress applying part 4 and the second stress applying part 10, and magnetic recording located ahead of the magnetic recording part 3d in which the magnetic recording is to be performed in the medium moving direction. A compressive stress in a direction parallel to the film surface of the portion 3c is generated. Thereby, the perpendicular magnetic anisotropy of the magnetic recording portion 3c sandwiched between the first stress applying portions 4 is improved by the inverse magnetostriction effect, and erroneous recording on the magnetic recording portion 3c can be prevented.

  In contrast, in the magnetic recording medium 1 of Example 1, the perpendicular magnetic anisotropy of the magnetic recording unit 3c is improved, but in this example, the current applied to the coil of the magnetic recording head 40 is increased so that the applied magnetic field is increased. Since the size of the disk exceeded the coercive force of the magnetic recording portion 3c, erroneous recording could not be prevented.

  Note that the magnetic recording medium 1 according to the present embodiment may have the configuration shown in FIG. FIG. 13 is a cross-sectional view showing a modification of the magnetic recording medium 11 according to the present embodiment and showing the configuration of the magnetic recording medium in which the nonmagnetic part 9 is formed in the upper layer of the first stress applying part 4. .

  The magnetic recording medium 60 is different from the magnetic recording medium 11 in that the nonmagnetic part 9 is formed in the upper layer of the first stress applying part 4. In other respects, the magnetic recording medium 60 has the same configuration as that of the magnetic recording medium 11, and thus the description thereof is omitted.

  As shown in FIG. 13, the magnetic recording medium 60 is formed between each of the plurality of magnetic recording portions 3, and the nonmagnetic portion 9 is formed in the upper portion of the first stress applying portion 4. . That is, the nonmagnetic portion 9 is in the film thickness direction of the first stress applying portion 4, and the nonmagnetic portion 9 is formed in the upper layer of the first stress applying portion 4. The thickness in the height direction of the first stress applying portion 4 and the nonmagnetic portion 9 is equal to the thickness in the height direction of the magnetic recording portion 3 and the second stress applying portion 10. Is formed.

  According to this, compared with the magnetic recording medium 1 in which the nonmagnetic part 9 is not formed, the thickness in the height direction of the first stress applying part 4 can be reduced. Here, as described above, the first stress applying portion 4 is made of a magnetic material having a relatively large magnetic anisotropy in the direction parallel to the film surface as compared to the direction perpendicular to the film surface. For this reason, the direction in which the first stress applying portion 4 has magnetization in the direction parallel to the film surface is more stable in terms of energy. Further, by reducing the thickness of the first stress applying portion, it is possible to stabilize the magnetic anisotropy in the direction parallel to the film surface by the shape magnetic anisotropy. For this reason, the perpendicular magnetic anisotropy of the magnetic recording unit 3b surrounded by the first stress applying unit 4 on the side surface in the direction perpendicular to the film surface is improved by the inverse magnetostriction effect, and erroneous recording is performed on the magnetic recording unit 3b. Can be prevented.

  Further, at the location where the nonmagnetic portion 9 is formed, the magnetic recording portion 3 and the magnetic recording portion 3 adjacent to the magnetic recording portion 3 (for example, the magnetic recording portion 3a and the adjacent magnetic recording portion 3b) are magnetically coupled. Therefore, the perpendicular magnetic information recorded in one magnetic recording unit 3 can be prevented from being transferred to the adjacent magnetic recording unit 3 by the exchange coupling force.

  In the present embodiment, as shown in FIG. 13, the nonmagnetic portion 9 is formed in the direction perpendicular to the film surface of the first stress applying portion 4, and the film thickness of the first stress applying portion 4 is the second thickness. The structure larger than the film thickness of the stress provision part 10 may be sufficient.

  According to this, the compressive stress from the second stress applying unit 10 is effectively applied to the magnetic recording unit 3b, and the perpendicular magnetic anisotropy of the magnetic recording unit 3b sandwiched between the first stress applying units 4a and 4b. Can be improved by the inverse magnetostriction effect, and erroneous recording on the magnetic recording portion 3b can be prevented.

  In FIG. 13, the first stress applying portion 4 and the nonmagnetic portion 9 are formed in the order of the first stress applying portion 4 and the nonmagnetic portion 9 when viewed from the substrate 2 side. The imparting part 4 and the nonmagnetic part 9 may be interchanged.

  Further, each of the magnetic recording media 1 and 11 relating to the first and second embodiments of the present invention and the magnetic recording media 21, 50 and 60 which are the modified examples apply an external magnetic field while locally heating a part thereof. Thus, the magnetic information may be recorded, that is, applied to an optical (thermal) assisted magnetic recording system.

  According to this, for example, on the magnetic recording medium 1, a heat distribution is generated with the magnetic recording portion 3 a where magnetic information is desired to be recorded as the central portion and the central portion at a high temperature. And since the temperature is raised to a high temperature in the vicinity of the boundary surface adjacent to the magnetic recording portion 3a in the stress applying portion 4a adjacent to both sides of the magnetic recording portion 3a, the magnetism is attenuated and the generation of magnetostriction is suppressed as much as possible. On the other hand, in the vicinity of the boundary surfaces between the magnetic recording unit 3b adjacent to the magnetic recording unit 3a and the first stress applying units 4a and 4b sandwiching the magnetic recording unit 3b, the temperature raised by the heat distribution is small. For this reason, since the amount of magnetism lost is small compared with the vicinity of the boundary surface between the stress applying portion 4a and the magnetic recording portion 3a in the high temperature portion, magnetostriction can be generated. Therefore, compared with the case where no heating is performed, the difference in stress applied to the magnetic recording unit 3a to be magnetically recorded and the adjacent magnetic recording unit 3b can be increased, thereby preventing the erroneous recording on the magnetic recording unit 3b. Can be further increased.

  In the first and second embodiments of the present invention, the effect of preventing erroneous recording has been described for the magnetic recording unit 3b positioned in the front of the medium moving direction with respect to the magnetic recording unit 3a to be magnetically recorded. A first stress applying portion 4 positioned in the track width direction with respect to the magnetic recording portion 3a to be subjected to magnetic recording, and a second stress applying formed in the film thickness direction of the adjacent magnetic recording portion positioned in the track width direction. A leakage magnetic field including an in-plane direction component is also applied to the portion 10. For this reason, it is possible to obtain an effect of preventing erroneous recording on the adjacent magnetic recording portion located in the track width direction with respect to the magnetic recording portion 3a to be subjected to magnetic recording.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, magnetic information can be recorded by improving the magnetic anisotropy in the direction perpendicular to the film surface. Therefore, the present invention can be widely applied to magnetic recording media that record magnetic information at high density.

FIG. 3 illustrates a configuration of a magnetic recording medium according to an embodiment of the present invention, and is a cross-sectional view taken along line A-A ′ illustrated in FIG. 2. 1 is a plan view illustrating a configuration of a magnetic recording medium according to an embodiment of the invention. 1 is a diagram illustrating a magnetic recording medium and a magnetic recording head according to an embodiment of the present invention, and is an explanatory diagram illustrating a state of a magnetic field when performing magnetic recording. FIG. FIG. 4A shows a manufacturing process of a magnetic recording medium according to an embodiment of the present invention, and is a cross section in which a soft magnetic layer, a first stress applying portion, and a resist are laminated on a substrate. FIG. 4B shows a cross-sectional view when the resist in FIG. 4A is patterned. FIG. 5A shows a manufacturing process of the magnetic recording medium according to the embodiment of the present invention, and shows a case where the first stress buoyancy of the magnetic recording medium in FIG. 4A is patterned. FIG. 5B is a cross-sectional view when the magnetic recording portion is formed in FIG. 5A. FIG. 6A shows a manufacturing process of the magnetic recording medium according to the embodiment of the present invention, and shows a cross-sectional view when the resist of the magnetic recording medium shown in FIG. FIG. 6B shows a cross-sectional view when a protective layer and a lubricating layer are formed on the magnetic recording medium of FIG. FIG. 7 is a cross-sectional view showing a configuration of a magnetic recording medium that is a comparative example of the magnetic recording medium according to the embodiment of the present invention. FIG. 8A shows a schematic diagram of the magnetic recording medium according to one embodiment of the present invention and the magnetic recording medium of the comparative example of FIG. 7, where the magnetization direction of the magnetic recording unit is the same direction. FIG. 8B is a cross-sectional view illustrating a case where the magnetization directions of the magnetization recording units in FIG. 8A are different. FIG. 9A shows a modification of the magnetic recording medium according to the embodiment of the invention, and shows a configuration in which a nonmagnetic part is formed between the magnetic recording part and the first stress applying part. FIG. 9B shows a modification of the magnetic recording medium according to the embodiment of the present invention, and shows a configuration in which a nonmagnetic part is formed in the upper layer of the first stress applying part. It is sectional drawing to represent. FIG. 10 is a cross-sectional view showing a configuration according to the second embodiment of the magnetic recording medium of the present invention. FIG. 11 is an explanatory diagram showing a cross section of the magnetic recording medium according to the second embodiment of the present invention and a magnetic recording head, and showing a state of a magnetic field when information is recorded. FIG. 12A shows a schematic configuration of the magnetic recording medium according to the second embodiment of the present invention and the magnetic recording medium according to the first embodiment, and the directions of magnetization of the magnetic recording portions are the same. FIG. 12B is a cross-sectional view illustrating a case where the magnetization directions of the magnetization recording units in FIG. 12A are different. FIG. 13 is a cross-sectional view showing the configuration of a modification of the magnetic recording medium according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic recording medium 2 Substrate 3 Magnetic recording part 4 First stress applying part 5 Soft magnetic layer 6 Protective layer 7 Lubricating layer 8 Resist 9 Nonmagnetic part 10 Second stress applying part 11 Magnetic recording medium 21 Magnetic recording medium 30 Magnetic Layer 31 Magnetic layer 40 Magnetic recording head 41 Main pole 42 Trailing shield 50 Magnetic recording medium 55 Magnetic recording medium 60 Magnetic recording medium

Claims (10)

In a magnetic recording medium comprising a magnetic layer to which magnetism is applied on a substrate,
The magnetic layer is made of a magnetic material having a relatively large magnetic anisotropy in a direction perpendicular to the film surface of the magnetic layer as compared to a direction parallel to the film surface of the magnetic layer. A plurality of magnetic recording units,
A first stress applying portion made of a magnetic material having a relatively large magnetic anisotropy in a direction parallel to the film surface of the magnetic layer as compared to a direction perpendicular to the film surface of the magnetic layer;
At least along the track on which information is recorded, the plurality of magnetic recording portions and the first stress applying portion are alternately arranged,
A magnetic recording medium, wherein the magnetostriction constants of the magnetic recording unit and the first stress applying unit are positive.   2. The magnetic recording medium according to claim 1, wherein each of the plurality of magnetic recording units is separated from each other, and a cross section in a direction parallel to the film surface is formed as a closed region. For each of the plurality of magnetic recording portions, a second stress applying portion is formed in the film thickness direction in the magnetic recording portion,
The second stress applying portion is made of a magnetic material having a relatively large magnetic anisotropy in a direction parallel to the film surface of the magnetic layer as compared with a direction perpendicular to the film surface, and has a negative magnetostriction constant. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is a magnetic recording medium.   The magnetic recording medium according to any one of claims 1 to 3, wherein a nonmagnetic portion made of a nonmagnetic material is formed between the magnetic recording portion and the first stress applying portion. .   5. The non-magnetic portion is formed between each of the plurality of magnetic recording portions, and the non-magnetic portion is formed in an upper portion or a lower portion in the first stress applying portion. 2. A magnetic recording medium according to claim 1.   The magnetic recording medium according to claim 3, wherein the magnetic bodies of the magnetic recording section, the first stress applying section, and the second stress applying section are all amorphous magnetic bodies.   The magnetic body of the magnetic recording portion comprises at least one rare earth metal selected from Gd, Ho, Tb, and Dy and at least one 3d transition metal selected from Fe and Co. Item 7. The magnetic recording medium according to any one of Items 1 to 6.   The magnetic body of the first stress applying portion comprises at least one rare earth metal selected from Gd, Ho, Tb, and Dy and at least one 3d transition metal selected from Fe and Co. The magnetic recording medium according to claim 1.   The magnetic recording medium according to claim 3, wherein the magnetic material of the second stress applying portion is made of SmFe.   10. A magnetic recording method for recording magnetic information by applying an external magnetic field while locally heating a part of the magnetic recording medium according to claim 1.

Images