JP2009158053A - Magnetic recording medium for tilt recording, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium capable of enhancing writing performance for a long time even when regularity of a regular alloy used for a recording layer is changed while the magnetic recording medium is efficiently heated with a small amount of energy consumption. <P>SOLUTION: The magnetic recording medium has such a structure that a soft magnetic layer 141 is formed on a rigid substrate 10, a soft magnetic layer 143 is formed thereon via a non-magnetic intermediate layer 142 and then an intermediate layer 16 composed of an oxide, a crystal orientation controlling and low thermal conduction intermediate layer 18, a granular recording layer 20 including essentially an Fe-Pt alloy composed of a composition expected to take an L1<SB>0</SB>structure at a stage where regulation is advanced, a cap layer 22 composed of an Fe-Pt alloy or a Co-Cr-Pt-B alloy, a protective layer 24 and a lubricant layer 26 are formed thereon. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic recording medium suitable for inclined recording that realizes high-density magnetic recording, and a method for manufacturing the same.

  Patent Document 1 proposes a magnetic recording medium in which a heat insulating layer is formed between a base and a magnetic recording layer for the purpose of heating the magnetic recording layer while minimizing the influence of heat on the base. Yes. Patent Document 3 proposes a magnetic disk in which a magnetic film is formed on the surface of a disk formed of a material having low thermal conductivity. In Patent Document 4, a nonmagnetic underlayer and a ferromagnetic layer are laminated on a nonmagnetic substrate, and the nonmagnetic underlayer has a thermal conductivity of 30 W / (m · K) or less in a temperature range of 20 ° C. to 300 ° C. There has been proposed a magnetic recording medium which is made of a material having the above structure and the ferromagnetic layer is made of a ferromagnetic metal containing Cr. In any of these magnetic recording media, in order to confine heat in the recording layer, a layer having a lower thermal conductivity than the recording layer is provided below the recording layer.

  On the other hand, Patent Document 2 includes a region of low thermal conductivity material that extends at least partially through the thickness of the thin film, and a region of high thermal conductivity material that separates the region of low thermal conductivity material, There has been proposed a thin film constructed and arranged such that these regions are regions of higher thermal conductivity than regions of low thermal conductivity and thermal conduction through the film thickness is greater.

Furthermore, magnetic recording media using intermetallic compounds have been proposed in order to realize high-density magnetic recording for hard disk drives. For example, a soft magnetic underlayer, the inclined recording magnetic recording medium having a L1 ₀ magnetic material with a top in (111) orientation of the soft magnetic underlayer has been proposed as described in Patent Document 5. In Patent Document 6, Cu to increase the ordering of the L1 ₀ structure, Au, Zn, perpendicular magnetic recording medium of the FePt alloy utilized with the addition of Sn and Pd have been proposed. Alternatively, a perpendicular magnetic recording medium in which the order of the CoPt and FePd alloys is improved instead of the FePt alloy has been proposed.

  Patent Document 7 shows an example of a heat-assisted recording method. Patent Document 8 also exemplifies a method of locally heating, such as using a near-field heater. Further, as described in Patent Document 9, a magnetic head having a thin film magnetic head element formed with a thin film resistor in which a magnetic pole tip is protruded by thermal expansion by energizing and generating heat as necessary, When a magnetic head reads / writes from / to a magnetic disk, a thin film resistor is formed by causing the tip of the magnetic pole to thermally expand by being energized to generate heat. It has been proposed that the gap between the magnetic disk surface and the magnetic disk surface be reduced by the protrusion of the magnetic pole tip. Patent Document 10 also proposes a head for a heat-assisted recording apparatus in which a magnetic pole is arranged on the upper part of a scatterer for generating near-field light at the bottom of a slider.

Japanese Unexamined Patent Publication No. 7-65357 JP 2006-196151 A JP 59-165243 JP-A-63-249925 JP 2006-19000 A Japanese Patent No. 3730518 US2006 / 0154110A1 US2002 / 0101673A1 JP-A-5-20635 JP 2007-128573 A

  Corresponding to the increase in surface recording density, it is necessary to refine the crystal grain size used for the recording layer. However, when the crystal grain size of the recording layer is reduced, the instability of the recording magnetization due to thermal fluctuation becomes remarkable. As countermeasures, (1) improvement in crystallinity of the recording layer, (2) reduction in crystal grain size dispersion, (3) use of a recording material having a large magnetic anisotropy, and (4) lamination of magnetic layers having different writing performances Proposal has been proposed. In particular, when using a recording material having a large magnetic anisotropy, it has been proposed to improve the writing performance by heating the recording layer to reduce the coercive force.

However, in a magnetic recording medium using a ferromagnetic material of an intermetallic compound, a metal having a composition that is expected to have an L1 ₀ structure at a stage where ordering has progressed by repeating writing by heating. A sufficient measure has not been taken about the possibility that the writing performance may be deteriorated due to an increase in the degree of order of the intermetallic compound and, as a result, an increase in magnetic anisotropy. In addition, no magnetic recording medium has been proposed in which the thermal conductivity is considered in the magnetic recording medium for tilt recording using the soft magnetic underlayer and the writing performance is improved at the same time. In consideration of the role of the soft magnetic underlayer in magnetic recording, a magnetic recording medium with a high crystallinity and thin low thermal conductivity layer that can close the gap between the soft magnetic underlayer and the recording layer has not been proposed. It was.

  From such a background, the problem to be solved by the present invention is to efficiently heat a magnetic recording medium with a small amount of energy consumption in consideration of thermal conductivity when magnetically writing to the magnetic recording medium. An object of the present invention is to provide a magnetic recording medium capable of improving the writing performance over a long period of time even if the degree of order of the ordered alloy used for the recording layer changes.

The magnetic recording medium for tilt recording according to the present invention is formed by forming a soft magnetic layer on a rigid substrate via an adhesive layer or directly on the substrate, and forming a soft magnetic layer on the soft magnetic layer via a nonmagnetic intermediate layer. , granular mainly containing constituted Fe-Pt alloy composition intermediate layer of oxide, the crystal orientation-control and low thermal conducting intermediate layer, take the L1 ₀ structure at the stage of progress in ordering is expected The recording layer, a cap layer made of an Fe—Pt alloy or a Co—Cr—Pt—B alloy, a protective layer, and a lubricating layer are formed in this order.

As the adhesive layer, not only an Al—Ti alloy but also a Cr—Ti alloy can be used. Instead of the intermediate layer made of an oxide, an intermediate layer made of a nonmagnetic Ni-based alloy may be provided. It may also contain a granular recording layer further Cu as a main component a consists Fe-Pt alloy composition take the L1 ₀ structure at the stage of progress in ordering is expected. These Fe—Pt alloys or Fe—Cu—Pt alloys are composed of a composition that is expected to have an L1 ₀ structure at the stage of regularization. ₂ or by addition of at least one oxide selected from oxides of TiO ₂ and Ta constituting the granular recording layer.

The crystal orientation control and low thermal conductivity intermediate layer may be a Ti—Al—V alloy or a Hastelloy C alloy. As a composition of Ti-Al-V alloy, Ti-6wt.% Al-4wt.% V alloy is mentioned as an industrially representative composition. In addition, as a generally distributed composition range, a material having a composition fluctuation of approximately ± 0.5 wt.% For each additive element may be used. Alternatively, between the granular recording layer mainly composed of composed Fe-Pt alloy composition taking L1 ₀ structure advanced crystal orientation-control and low thermal conductivity intermediate layer and regularization is stage is expected, A crystal orientation control layer made of Ru may be formed.

Instead of an Fe-Pt alloy composed of a composition that is expected to have an L1 ₀ structure at the stage of progress in ordering, it is composed of a composition that is expected to have an L1 ₀ structure at the stage of progress in ordering. Co-Pt alloy may be used. When using a Co-Pt alloy consisting of a composition which is expected to ordering the granular recording layer is in an advanced stage taking an L1 ₀ structure, it may be added to replace the Ni relative to Co. These Co-Pt alloy or Co-Ni-Pt alloy is formed of a composition is expected to take an L1 ₀ structure at the stage of progress in ordered, further oxidized to compositions which comprise these intermetallic compounds A granular recording layer is formed by adding a material.

A soft magnetic layer is formed on a rigid substrate via an adhesive layer or directly on the substrate, and the soft magnetic layer is formed on the soft magnetic layer via a nonmagnetic intermediate layer. in an intermediate layer made of oxide, the crystal orientation-control and low thermal conducting intermediate layer, the Fe-Pt alloy or Co-Pt alloy consisting of a composition which is expected to take an L1 ₀ structure at the stage of progress in ordering By forming a granular recording layer as a main component, a cap layer made of an Fe—Pt alloy, a Co—Pt alloy or a Co—Cr—Pt—B alloy, a protective layer, and then performing a heat treatment, and then forming a lubricating layer, L1 ₀ structure of the granular recording layer to improve the degree of order of the alloy portion that is expected, it is possible to manufacture a gradient recording magnetic recording medium of the present invention. The Pt composition of the Fe—Pt alloy or Co—Pt alloy used for the cap layer may be less than 40 at.%. If the concentration of Pt added is excessively reduced, the corrosion resistance deteriorates, so it is sufficient that the Pt content is 20 at.% Or more.

  According to the present invention, it is possible to provide a magnetic recording medium for tilt recording that can reduce power consumption and heat the magnetic recording medium, and at the same time has excellent writing performance.

  In the present invention, in a magnetic recording medium for tilt recording using a soft magnetic underlayer, in order to reduce the distance between the soft magnetic underlayer and the recording layer, the recording layer is heteroepitaxially grown on the crystal orientation control and low thermal conductivity intermediate layer. The distance between the soft magnetic underlayer and the recording layer was optimized. At the same time, by reducing the thermal conductivity of the crystal orientation control and low thermal conductivity intermediate layer, the coercivity of the recording layer can be reduced without heating to the soft magnetic underlayer, and magnetization reversal is possible with low power consumption.

  Forming a soft magnetic underlayer on a rigid substrate via an adhesive layer is preferable because mechanical reliability is improved. When the thickness of the soft magnetic underlayer is about 30 nm or less, the adhesive stress is not necessarily provided because the film stress is small. When an oxide film is formed on a soft magnetic underlayer, the thermal conductivity of the oxide film is about 1 W / (m · K), which is smaller than that of a metal film. Therefore, the recording layer is heated without heating the soft magnetic underlayer during recording. It becomes easy to do. Further, when a crystal orientation control and low thermal conductivity intermediate layer is formed on the intermediate layer made of oxide, the dense surface of the alloy intermediate layer grows parallel to the substrate surface. As a result, the granular recording layer formed on the crystal orientation control and low thermal conduction intermediate layer is heteroepitaxially grown with the (111) plane parallel to the substrate surface. When a Ti-Al-V alloy having a bulk thermal conductivity of 7.5 W / (m · K) is used as a crystal orientation control and low thermal conduction intermediate layer and a bulk thermal conductivity is 7.5 W / (m · K), a dense hexagonal filling structure is used. The (001) plane grows in parallel with the substrate surface. Alternatively, when a Hastelloy C alloy having a bulk thermal conductivity of 12 W / (m · K) is used as the crystal orientation control and low thermal conductivity intermediate layer, the (111) plane of the face-centered cubic structure is parallel to the substrate surface. grow up. Whereas Ti is a low thermal conductivity material of about 17 W / (m · K), the alloy for controlling crystal orientation and the low thermal conductivity intermediate layer is an alloy having a smaller thermal conductivity and easy to control the crystal orientation. is there. If these crystal orientation control and low thermal conductivity intermediate layers are thin, the crystal orientation and grain size can be controlled simultaneously, and the grain size and crystal growth orientation of the recording layer formed thereon can also be controlled. A dense hexagonal packing structure is formed between the recording layer and the crystal orientation control / low thermal conductivity intermediate layer to form a surface that is high in the range of 105 to 117 W / (m · K) but hardly affected by the atmosphere of the vacuum process. It is also effective to form a Ru layer whose (001) plane grows parallel to the substrate surface.

The Fe-Pt alloy in forming the granular recording layer mainly, the addition of Fe to replace with Cu, since easily forming an L1 ₀ ordered structure preferred. The Co-Pt alloy in forming the granular recording layer mainly composed, even if Co is added to replace at Ni, since easily forming an L1 ₀ ordered structure preferred. To granulate the recording layer, Ta oxide or a mixture thereof can be added in addition to SiO ₂ and TiO ₂ .

Rules of the L1 ₀ ordered alloy immediately after the formation of the magnetic recording medium is not necessarily high. However, as heating recording is repeated, the regularity gradually improves and the coercive force increases. Even if the coercive force of the granular recording layer is increased, no problem occurs in writing performance by forming a cap layer on the granular recording layer that triggers magnetization reversal. The material that can be used as the cap layer may be any material that has a smaller anisotropic magnetic field than the granular recording layer. For example, a cap layer made of an Fe—Pt alloy, a Co—Pt alloy, a Co—Cr—Pt—B alloy, or the like having a higher Co or Fe concentration than Pt can be used.

  The effect of the composition of the cap layer made of the Co—Cr—Pt—B alloy is as follows. When the Pt and B concentrations were fixed and the ratio of Co and Cr was changed, the writing performance was improved by increasing the Cr concentration, but the writing track width was increased. From this viewpoint, the addition concentration of Cr is preferably about 20 at.% In the case of a Co—Cr-12 at.% Pt-8 at.% B alloy. From the viewpoint of corrosion resistance reliability, the lower limit of the Cr addition concentration is 12 at.%. That is, Co- (12-20) at.% Cr-12 at.% Pt-8 at.% B is preferable. In the case of a Co-15at.% Cr-12at.% Pt-B alloy, the upper limit concentration of B is preferably about 10 at.% From the viewpoint of ease of making a target, and regeneration by coarsening of the crystal grain size. From the viewpoint of noise, the lower limit of the B addition concentration is 4 at. When the concentrations of Co and Pt were changed while the concentrations of Cr and B were fixed, the overwrite characteristics deteriorated as the Pt concentration was increased. From this viewpoint, the upper limit of the Pt concentration is preferably 16 at. If Pt is not added, the corrosion resistance reliability is lowered, so it is preferable to add 4 at.% Or more of Pt. From these results, in the case of Co-Cr-Pt-B alloy, Co- (12-20) at.% Cr- (4-16) at.% Pt- (4-10) at.% B alloy Is preferably used.

  As a protective layer to be provided after the cap layer is formed, in addition to a protective layer mainly composed of carbon containing nitrogen or hydrogen, it is also possible to form a protective layer mainly composed of silicon nitride from the viewpoint of ease of heating. To preferred.

  If an intermediate layer made of a nonmagnetic Ni-based alloy is provided instead of the “interlayer made of oxide”, it is possible to stop elution of ions caused by the soft magnetic underlayer, which is preferable in terms of improving reliability. Specific alloy systems include Ni-Ti, Ni-Ta, Ni-W, Ni-Cr, Ni-Cr-Ti, Ni-W-Cr, and Ni-Ta-Cr alloys. When a material selected from Ti, Ta, and W is added to Ni, the crystal grains can be refined, and the (111) plane having a face-centered cubic structure can be grown in parallel to the substrate surface. It is also possible to control the grain size and crystal growth of the low thermal conductivity intermediate layer with orientation control. It is also preferable to form a crystal orientation control layer made of Ru between the crystal orientation control and low thermal conductivity intermediate layer and the granular recording layer mainly composed of Fe—Pt alloy.

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

  FIG. 1 is a cross-sectional view showing the configuration of the magnetic recording medium according to the first embodiment. This magnetic recording medium includes an adhesive layer 12, a soft magnetic underlayer 141, a nonmagnetic layer 142, a soft magnetic underlayer 143, an oxide intermediate layer 16, a crystal orientation control / low thermal conductivity intermediate layer 18 on a substrate 10, granular recording. It has a layer 20, a cap layer 22, a protective layer 24 and a lubricating layer 26.

Next, a method for manufacturing a magnetic recording medium will be described. A chemically strengthened glass substrate having a thickness of 0.508 mm and an outer diameter of 48 mm was used as the substrate 10. All chambers were evacuated to a vacuum of 2 × 10 ⁻⁵ Pa or less using an in-line single-wafer DC / RF magnetron sputtering apparatus. Thereafter, the carrier on which the substrate 10 was placed was moved to each process chamber, the granular recording layer 20 was removed, the discharge Ar gas pressure was 0.7 Pa, and the following thin film was formed by DC magnetron sputtering. The method for forming the thin film is not limited to DC magnetron sputtering. For the formation of the granular recording layer 20, a high-frequency magnetron sputtering method was used in order to increase the expected crystallinity of the ordered alloy. Moreover, it is also possible to use DC pulse sputtering together when forming a thin film containing an oxide.

  In this example, a substrate obtained by chemically strengthening the substrate surface made of borosilicate glass or aluminosilicate glass was used as the glass substrate 10 after being washed and dried. Instead of a chemically strengthened glass substrate, a substrate whose surface is polished after Ni-P plating on an aluminum alloy substrate, or a rigid substrate made of Si or Ti alloy can also be used. The outer diameter of the substrate is not limited to 48 mm, and can be selected from 65 mm, 84 mm, and the like. The thickness of the substrate can also be selected as long as the rigidity is maintained, and can be selected from 0.635 mm, 0.8 mm, or the like. As the adhesive layer 12, a 50 at.% Al-50 at.% Ti alloy film having a thickness of 5 nm was formed.

  After forming a 51 at.% Fe-34 at.% Co-10 at.% Ta-5 at.% Zr alloy film as the soft magnetic layer 141 and forming a 0.7 nm thick Ru film as the nonmagnetic layer 142 A 51 at.% Fe-34 at.% Co-10 at.% Ta-5 at.% Zr alloy film having a thickness of 20 nm was again formed as the soft magnetic underlayer 143. The composition of the soft magnetic layers 141 and 143 is not limited to the above composition. However, when the concentration of the added elements of Ta and Zr is 5 at.% In total, the oxide intermediate layer 16 stabilized in an oxidation process within 5 seconds. Could be formed. When the total concentration of the added elements of Ta and Zr was 20 at.%, The write characteristics were improved by making the soft magnetic underlayers 141 and 143 thicker than 20 nm, respectively. Instead of the 51at.% Fe-34at.% Co-10at.% Ta-5at.% Zr alloy, the concentration of the added elements of Ta and Zr is fixed at 15at.%, For example, 48at.% Fe-37at.%. It is also possible to change to a Co-10 at.% Ta-5 at.% Zr alloy. From the measurement result of the reflection curve by X-ray diffraction, it is considered that all of these Fe—Co—Ta—Zr alloy films are microcrystalline or amorphous.

  As the non-magnetic layer 142, Ru-50at.% Fe alloy, Ru-40at.% Cr alloy, Ru-30at.% Co alloy or the like can be used as an alloy containing Ru or Ru as a main component. The film thickness can be changed within a range where the soft magnetic layers 141 and 143 can be antiferromagnetically coupled. Furthermore, if the residual magnetizations of the soft magnetic layers 141 and 143 are made antiparallel to each other by using this antiferromagnetic coupling, reproduction noise can be reduced. After forming the soft magnetic underlayer 143, the oxide intermediate layer 16 was formed by exposing Ar gas containing 1 vol.% Oxygen for 5 seconds.

  After forming the oxide intermediate layer 16, the substrate temperature was heated to 280 ° C., and a Ti-6 wt.% Al-4 wt.% V alloy film was formed to 2 nm to 20 nm as the crystal orientation control and low thermal conduction intermediate layer 18. The thermal conductivity of bulk Ti is 17 W / (m · K), whereas the thermal conductivity of Ti—Al—V alloy is 7.5 W / (m · K), which is less than half of Ti.

Further, a 92 mol% (50 at.% Fe-50 at.% Pt) -8 mol% SiO ₂ film having a thickness of 12 nm was formed as the granular recording layer 20. The Ar gas pressure for discharge when forming the granular recording layer 20 was 2 Pa.

  About these samples, the reflection diffraction curve using the characteristic X-ray of copper was measured. As a result, it was confirmed that the 002 diffraction intensity derived from the hcp structure increases as the thickness of the Ti-6 wt.% Al-4 wt.% V alloy film increases. Along with this increase in diffraction intensity, an increase in 111 diffraction intensity derived from the fcc structure or the fct structure, which is considered to be caused by the granular recording layer, was observed. From this, it was confirmed that this medium is an inclined recording medium in which the easy axis of magnetization of the recording layer is inclined from the direction perpendicular to the film surface.

  After the granular recording layer 20 is formed, a cap layer 22 made of 65 at.% Fe-35 at.% Pt alloy or Co-15 at.% Cr-12 at.% Pt-8 at. Alternatively, the protective layer 24 containing hydrogen and containing carbon as a main component was formed to 3 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere substituted with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 containing fluorine as a main component.

  After confirming the mechanical flying characteristics, recording was performed with a writing pole having a geometric track width PW of 105 nm, and the electromagnetic conversion characteristics of the magnetic recording medium were measured using a TMR head having a shield gap length of 35 nm. FIG. 2 is a cross-sectional view centered on a recording head in which a single magnetic pole head and a scatterer for generating near-field light are combined. A scatterer 34 for generating near-field light was formed on the surface of the slider 32, and a magnetic pole 36 was formed thereon. Light was generated using a semiconductor laser 38 having a wavelength of 785 nm, and the light generated from the semiconductor laser 38 was guided to the scatterer 34 using a waveguide composed of a core portion 40 and a cladding portion 42. The core portion 40 of the waveguide is surrounded by a clad portion 42. A magnetic field generated using the thin film coil 44 was guided near the scatterer 34 by the main magnetic pole 46. The main magnetic pole 46 and the thin film coil 44 are arranged on the outflow end 48 side with respect to the waveguide. The magnetic pole 36 and the main magnetic pole 46 on the upper part of the scatterer 34 are coupled using the magnetic pole 50. An auxiliary magnetic pole 52 for forming a closed magnetic circuit is formed on the opposite side of the thin film coil 44 via the magnetic pole 51. A coil 44 is linked to a magnetic circuit formed by the magnetic pole 36, the magnetic pole 50, the main magnetic pole 46, the magnetic pole 51, and the auxiliary magnetic pole 52 on the scatterer 34. A magnetic reproducing element 54 for reproducing a recording signal is formed beside the waveguide. A shield 56 for shielding a magnetic field from the surroundings is formed around the magnetic reproducing element 54. This reproducing element may be placed beside the auxiliary magnetic pole 52 (on the outflow end 48 side), but in this embodiment, the reproducing element is arranged as shown in FIG. 2 and a TMR element is used as the magnetic reproducing element 54. A thin film resistor 58 was formed in which the reproducing element 54 was thermally expanded and protruded by energizing and generating heat as necessary.

  During recording, heating was performed using a 100 mW semiconductor laser 38 having a wavelength of 785 nm. The electromagnetic conversion characteristics were evaluated under the condition that the thin film resistor 58 was energized with 60 mW without using the semiconductor laser 38 during reproduction.

  The magnetic recording medium was rotated at 90 / s (= 5400 pm), and the skew angle of the head was 0 degree with a radius of 21 mm. Overwrite characteristic (O / W) is demagnetized at 47.2 kFC / mm (= 1200 kFCI), then a 35.4 kFC / mm (= 900 kFCI) signal is written, and a 7.01 kFC / mm (= 178 kFCI) signal is superimposed. The unerased remainder of the written 35.4 kFC / mm signal was evaluated. During reproduction, 60 mW was passed through the thin film resistor 58 to generate heat, and the electromagnetic conversion characteristics were measured. The time-dependent change with respect to the number of writings was measured on the same track by heating in parallel.

  As a result, even after overwriting 10,000 times with respect to the overwrite characteristic in the initial stage of heating, the overwrite characteristic is within an error range of ± 0.2 dB, and even if the degree of ordering of the ordered alloy changes. It became clear that there was no problem in writing performance for a long time. When the cap layer 22 was formed to have a thickness of 4 nm or more, the overwrite characteristics were improved as shown in FIG.

  On the other hand, the write track width became wider as the cap layer 22 became thicker. FIG. 4 shows the relationship between the write track width (Tw) normalized by the geometric track width (Pw) and the thickness of the cap layer 22. The tendency of increasing the (Tw / Pw) value when the thickness of the cap layer was increased was not dependent on the material of the cap layer. From these results, the thickness of the cap layer needs to be at least about 4 nm, but it is considered that the thickness should be about 7 nm in consideration of the increase in the track width.

[Comparative Example 1]
After forming the soft magnetic underlayer 143 in Example 1, the substrate temperature was heated to 280 ° C. on the soft magnetic underlayer 143 without exposing Ar gas containing 1 vol.% Oxygen for 5 seconds. Instead of forming a Ti-6 wt.% Al-4 wt.% V alloy film as the orientation control and low thermal conduction intermediate layer 18, a 10 nm Ti film was formed as the crystal orientation control intermediate layer. In other processes, after forming the granular recording layer 20 under the same conditions as in Example 1, a cap layer 22 made of a Co-15 at.% Cr-12 at.% Pt-8 at.% B alloy is formed from 3 nm to 10 nm, and nitrogen is added. Alternatively, the protective layer 24 containing hydrogen and containing carbon as a main component was formed to 3 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere substituted with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 containing fluorine as a main component. These magnetic recording media are evaluated using the evaluation conditions described in Example 1, that is, 100 mW of semiconductor laser 38 having a wavelength of 785 nm is heated during recording, and 60 mW is applied to thin film resistor 58 without using semiconductor laser 38 during reproduction. The electromagnetic conversion characteristics were evaluated under the conditions. As a result, the O / W deteriorated from 3 dB to 5 dB as compared with Example 1 in any cap layer thickness sample.

  On the other hand, as a result of increasing the power consumption to 110 mW during recording, heating using the semiconductor laser 38 having a wavelength of 785 nm, and evaluating the electromagnetic conversion characteristics under the condition that the thin film resistor 58 is energized by 60 mW without using the semiconductor laser 38 during reproduction. O / W characteristics comparable to those of Example 1 were obtained.

  The thermal conductivity of bulk Ti is 17 W / (m · K), whereas the thermal conductivity of Ti-Al-V alloy is 7.5 W / (m · K). It was found that if the thermal conductivity of the orientation control and low thermal conductivity intermediate layer is less than half that of Ti, the power consumption during recording for obtaining the same O / W characteristics can be reduced.

After forming the soft magnetic underlayer 143 in Example 1, it was once taken out into the atmosphere, and the following post-process was set with another film forming apparatus. After evacuated to 2 × 10 ^-5 Pa or less, and heated to 300 ° C., and the coating selected from oxides of magnesium oxide or Ti to 5nm formed from 2nm as the intermediate oxide layer 161. After forming the oxide intermediate layer 161, a Ti-5.8 wt.% Al-4.3 wt.% V alloy film was formed to 5 nm as the crystal orientation control and low thermal conductive intermediate layer 18. Furthermore, 12 nm of (50 at.% Fe-50 at.% Pt)-(8, 10, 12 mol% SiO ₂ film was formed as the granular recording layer 20. When forming the granular recording layer 20, the Ar gas pressure for discharge was set to 2 Pa. It was.

  For these samples having the cross-sectional configuration shown in FIG. 5, the average crystal grain size of the granular magnetic layer was measured. The average crystal grain size <D> was calculated from a transmission electron microscope (TEM) image. First, a crystal grain image of the recording layer in a direction parallel to the substrate surface was taken with a transmission electron microscope. Next, the obtained photograph was captured by a scanner, the core portion where the contrast of the image was observed was defined as a crystal grain, and the number of pixels present in each crystal grain was calculated. From the conversion of the number of pixels and the scale, the area of each crystal is obtained, the crystal grain size is defined as the diameter of a perfect circle having the same area as the obtained crystal grain area, and the grain diameter Di of each crystal grain is obtained. It was. This calculation was performed for about 300 crystal grains, and the arithmetic average value of the obtained particle diameters was defined as the average crystal grain diameter <D>.

In the Fe—Pt—SiO ₂ film added with 8 mol% SiO ₂ , the average crystal grain size <D> was about 8 nm. In the Fe—Pt—SiO ₂ film added with 10 mol% SiO ₂ , <D> was 6.4 nm. Furthermore, in the Fe—Pt—SiO ₂ film to which 12 mol% SiO ₂ was added, <D> decreased to 5.3 nm.

  It was confirmed that the 002 diffraction intensity derived from the hcp structure increases as the Ti—Al—V alloy film becomes thicker. As the X-ray diffraction intensity from the intermediate layer increased, an increase in 111 diffraction intensity derived from the fcc structure or fct structure of the recording layer was also observed. From the behavior of these X-ray diffraction intensities, it is considered that the intermediate layer having the hcp structure and the recording layer formed thereon are heteroepitaxially grown.

  After forming the granular recording layer 20, as shown in FIG. 6, a cap layer 22 made of a 65 at.% Fe-35 at.% Pt alloy or a Co-16 at.% Cr-10 at.% Pt-6 at. The protective layer 24 containing nitrogen or hydrogen and containing carbon as a main component was formed to 2.5 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere substituted with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 containing fluorine as a main component.

  After confirming the mechanical levitation characteristics, the same head as in Example 1 was used, and heating was performed using a semiconductor laser 38 having a wavelength of 785 nm of 80 mW during recording, and 60 mW was applied to the thin film resistor 58 without using the semiconductor laser 38 during reproduction. The electromagnetic conversion characteristics were measured under heating conditions. As a result, when the cap layer 22 was formed to have a thickness of 4 nm or more, the overwrite characteristics were improved. On the other hand, the write track width became wider as the cap layer 22 became thicker. This tendency, that is, the tendency that the track width becomes wider as the cap layer becomes thicker was the same even when the material of the cap layer was changed. From these results, the thickness of the cap layer is required to be at least about 4 nm, but it is considered that the thickness should be about 6 to 7 nm in consideration of the increase in the track width.

  When recording using the same head as in the first embodiment, light is generated using a semiconductor laser 38 with a wavelength of 785 nm of 80 mW and heated during recording, and when reproducing, the semiconductor laser 38 with a wavelength of 785 nm is not used and the thin film resistor 58 is energized with 60 mW. Even when the electromagnetic conversion characteristics were measured under heating conditions, O / W characteristics comparable to those of Example 1 were obtained. As a result, by heating to 300 ° C. and forming a film selected from oxides of magnesium oxide and Ti as the oxide intermediate layer 161 from 2 nm to 5 nm, the crystal orientation can be controlled, and the low thermal conductivity intermediate layer is thickened. This is considered to be because heat flow was hindered by the formation, and the recording layer could be effectively warmed easily.

  As described above, after forming a film selected from magnesium oxide or Ti oxide as the oxide intermediate layer 161 from 2 nm to 5 nm, Ti-5.8 wt.% Al-4 as the crystal orientation control and low thermal conductive intermediate layer 18 is formed. When a 5 wt.% V alloy film was formed to a thickness of 5 nm (Example 2), sufficient O / W characteristics were obtained even with heating of about 80 mW during writing. On the other hand, in the case of a medium having a thin oxide layer described in Example 1, 80 mW heating is insufficient at the time of writing in order to obtain the same O / W characteristics as in Example 2, and heating of 100 mW is insufficient. It was necessary. From the comparison of these power consumptions, it has become clear that the formation of the oxide intermediate layer 161 is also effective in reducing the power consumption.

A magnetic recording medium for tilt recording whose cross-sectional schematic diagram is shown in FIG. 7 was produced. After forming the soft magnetic underlayer 143 in Example 1, the oxide intermediate layer 16 is not formed, and the nonmagnetic intermediate layer 17 made of a Ni—Cr—W alloy is formed to a thickness of 5 nm. A Ti-5.5 wt.% Al-3.7 wt.% V alloy film was formed as the conductive intermediate layer 18 so as to have a thickness of 3 nm to 10 nm. Further, after forming a 90 mol% (50 at.% Fe-50 at.% Pt)-(10 mol% SiO ₂ ) film with a thickness of 11 nm, a cap layer 22 made of a Co-18 at.% Cr-10 at.% Pt-8 at.% B alloy is formed. The thickness was 3 nm to 10 nm. Further, a protective layer 24 containing nitrogen or hydrogen and containing carbon as a main component was formed to 3.3 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere purged with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 composed mainly of perfluoropolyether.

  After confirming mechanical levitation characteristics, the head described in Example 1 was used, and heating was performed using a semiconductor laser 38 having a wavelength of 785 nm of 100 mW during recording, and 60 mW was applied to the thin film resistor 58 without using the semiconductor laser 38 during reproduction. The electromagnetic conversion characteristics were measured under the condition of current heating. As a result, when the cap layer 22 was formed to have a thickness of 4 nm or more, the overwrite characteristics were improved by 4 dB or more compared to the case where the cap layer 22 was not formed. On the other hand, when the cap layer 22 is thick, the write track width is widened. With respect to the medium having a thickness of 5 nm as the cap layer 22, 85 mW semiconductor laser (wavelength 785 nm) 38 is used to generate light and heated during recording, and during reproduction, the semiconductor laser 38 is not used, and the thin film resistor 58 is heated by 60 mW energization. The electromagnetic conversion characteristics were measured under the following conditions. As a result, when the power of the semiconductor laser (wavelength 785 nm) during recording is reduced from 100 mW to 85 mW, −31 dB is obtained although the O / W characteristics are deteriorated, and the power consumption of the semiconductor laser (wavelength 785 nm) may be reduced. Became clear.

In forming the granular recording layer described in Example 3, instead of forming 11 mol of 90 mol% (50 at.% Fe-50 at.% Pt) -10 mol% SiO ₂ , a granular recording layer made of the following alloy was formed. A magnetic recording medium was formed in the same manner as in Example 3 except for the above.
92 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-8 mol% SiO ₂
90 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-10 mol% SiO ₂
88 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-12 mol% SiO ₂
86 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-14 mol% SiO ₂
84 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-16 mol% SiO ₂
80 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-20 mol% SiO ₂
72 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-28 mol% SiO ₂
60 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-40 mol% SiO ₂
50mol% [(45at% Fe- 5at% Cu-50at% Pt...)] - 50mol% SiO 2
90 mol% [(47 at.% Fe-3 at.% Cu-50 at.% Pt)]-10 mol% SiO ₂
90 mol% [(40 at.% Fe-10 at.% Cu-50 at.% Pt)]-10 mol% SiO ₂

  After the granular recording layer 20 was formed, a cap layer 22 made of a Co-18 at.% Cr-10 at.% Pt-8 at.% B alloy was formed to a thickness of 3 to 10 nm. Further, a protective layer 24 containing nitrogen or hydrogen and containing carbon as a main component was formed to 3.3 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere substituted with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 containing fluorine as a main component.

After confirming the mechanical flying characteristics, the same head as in Example 1 was used, and heating was performed using a semiconductor laser 38 having a wavelength of 785 nm of 100 mW during recording. During reproduction, the semiconductor laser 38 was not used, and the electromagnetic conversion characteristics were measured under the condition that the thin film resistor 58 was energized with 60 mW. As a result, when the cap layer 22 was formed to have a thickness of 4 nm or more, the overwrite characteristic was improved by 4 dB or more compared to the case where the cap layer 22 was not formed. The composition of the granular recording layer (100-x) mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-x mol% SiO ₂ with respect to the overwrite characteristics when a cap layer having a thickness of 4 nm is formed. The dependency is shown in FIG. When the addition concentration of SiO ₂ was increased from 8 mol% to 50 mol%, the overwrite characteristics deteriorated, and when the composition of SiO ₂ exceeded 30 mol%, the overwrite characteristics became −20 dB or more (the absolute value was small). On the other hand, as the cap layer 22 becomes thicker, the write track width becomes wider.

So / Nd logarithmically expressing the ratio of medium noise Nd and reproduction signal output So and granular recording layer (100-x) mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-x mol% SiO The relationship between the _two compositions is shown in FIG. From this figure, the So / Nd of the granular recording layer to which 28 mol% SiO ₂ was added was almost equal to that of the granular recording layer to which 8 mol% SiO ₂ was added. However, if will be higher than 28 mol% SiO ₂ the concentration of added SiO _2, So / Nd with overwrite characteristic is deteriorated. From these results, it became clear that the upper limit of the concentration of SiO ₂ added to (45 at.% Fe-5 at.% Cu-50 at.% Pt) is preferably 28 mol%.

[Comparative Example 2]
When forming the granular recording layer described in Example 3, instead of forming a 90 mol% (50 at.% Fe-50 at.% Pt) -10 mol% SiO ₂ film to 11 nm, 92 mol% [(45 at.% Fe-5 at.% Zn −50 at.% Pt)]-8 mol% SiO ₂ film was formed. As a result of X-ray fluorescence analysis of the granular film formed in the initial stage and the granular film manufactured the next day, the composition of Zn contained in the granular recording layer was lowered. From this result, it became clear that when the alloy target for forming the granular film is held in a vacuum, it is necessary to manage the change in the Zn concentration in consideration of the composition variation during mass production and the stability of the magnetic characteristics.

  After forming the soft magnetic underlayer 143 in Example 1, the oxide intermediate layer 16 was not formed, and the nonmagnetic intermediate layer 17 made of Ni—Cr—W alloy was formed to a thickness of 5 nm, and then the thickness was changed from 3 nm to 10 nm. Thus, a crystal orientation control / low thermal conductivity intermediate layer 18 made of Hastelloy C alloy was formed (FIG. 7). Thereafter, a magnetic recording medium was formed in the same manner as in Example 3. The thermal conductivity of the Hastelloy C alloy used in this example is about 12 W / (m · K) in bulk, and the thermal conductivity of Ti is about 70%.

  After confirming the mechanical flying characteristics, the same head as in Example 1 was used, and light was generated and heated using a semiconductor laser 38 having a wavelength of 785 nm of 100 mW during recording. During reproduction, the semiconductor laser 38 was not used, and the electromagnetic conversion characteristics were measured under the condition that the thin film resistor 58 was energized with 60 mW. As a result, the overwrite characteristics were improved as the thickness of the crystal orientation control / low thermal conductivity intermediate layer 18 made of Hastelloy C alloy was increased from 3 nm to 10 nm. This tendency is considered to be due to the fact that as the thickness of the intermediate layer having low heat conduction is increased, the heat conduction is less likely in the film thickness direction, and as a result, the temperature of the granular layer is likely to rise, thereby improving the writing performance.

A magnetic recording medium for tilt recording whose cross-sectional schematic diagram is shown in FIG. 10 was produced. In Example 4, 92 mol% [(45 at.% Fe-5 at.% Cu-50 at.% Pt)]-8 mol% Before forming the SiO ₂ granular recording layer, the film thickness was changed from 0.4 nm to 6 nm and from Ru. The resulting crystal orientation control layer 19 was formed. Other than this, a magnetic recording medium was formed in the same manner as in Example 4.

  As a result of measuring the magnetic characteristics of the magnetic recording medium using the Kerr effect by applying a magnetic field of up to 1.6 MA / m, by providing the crystal orientation control layer 19 made of Ru, the vertical component of the coercive force is 45 kA / m increased.

Further, using an X-ray diffractometer using a copper rotating counter cathode, the half-value width Δθ ₅₀ of the Ru 004 diffraction curve was measured at an acceleration voltage of 40 kV and a current of 160 mA. As a result of forming the granular recording layer 20 via Ru as the crystal orientation control layer 19 on the crystal orientation control / low thermal conduction intermediate layer 18 made of Ti-5.5 wt.% Al-3.7 wt.% V alloy, The granular recording layer 20 chemically grows on the crystal orientation control layer 19 in a stable manner, <D> increases from 8.1 nm to 8.5 nm, and Δθ ₅₀ that is an index of crystallinity is also 3.5 °. The improvement from 3.1 to 3.1 ° was achieved at the same time. When Ru is made thicker as the crystal orientation control layer 19, the distance between the soft magnetic layer 143 and the granular recording layer 20 becomes too large. If the Ru thickness of the crystal orientation control layer 19 is 2 nm to 4 nm, sufficient writing performance can be obtained.

  A magnetic recording medium was manufactured in the same manner as in Example 1 except that the composition of the Co—Cr—Pt—B alloy was changed for the cap layer 22 used in Example 1. After confirming the mechanical flying characteristics, the same head as in Example 1 was used, and during recording, heating was performed using a semiconductor laser 38 with a wavelength of 785 nm of 100 mW. During reproduction, the semiconductor laser 38 was not used, and the electromagnetic conversion characteristics were measured under the condition that the thin film resistor 58 was energized with 60 mW.

  As a result, in the case of a Co—Cr-12 at.% Pt-8 at.% B alloy in which the concentration of Pt and B is fixed and the ratio of Co and Cr is changed, the writing performance is lowered by increasing the Cr concentration. , Writing track width decreased.

  When the thickness of the cap layer 22 is fixed to 6 nm, O / W decreases to −24.3 dB when using a 58 at.% Co-22 at.% Cr-12 at.% Pt-8 at.% B alloy cap layer. did. In the case of using a 60 at.% Co-20 at.% Cr-12 at.% Pt-8 at.% B alloy cap layer having a reduced Cr concentration relative to Co, the O / W was improved to -27.1 dB. From these results, by setting the Cr concentration to 20 at.% Or less, it is possible to achieve −25 dB or less, which is a standard for the O / W index. From this viewpoint, when the thickness of the cap layer 22 is fixed to 6 nm, the upper limit of the Cr addition concentration of the Co—Cr-12 at.% Pt-8 at.% B alloy is preferably about 20 at.%. From the viewpoint of corrosion resistance reliability, the lower limit of the Cr addition concentration was preferably 12 at.%. That is, Co- (12-20) at.% Cr-12 at.% Pt-8 at.% B is preferable.

  In the case of a Co-16 at.% Cr-Pt-8 at.% B alloy in which the concentrations of Co and Pt were changed while the concentrations of Cr and B were fixed, the overwrite characteristics deteriorated when the Pt concentration was increased.

  When the thickness of the cap layer 22 is fixed to 6 nm, the O / W decreases to −23.8 dB when using a 58 at.% Co-16 at.% Cr-18 at.% Pt-8 at.% B alloy cap layer. did. On the other hand, in the case of using 60 at.% Co-16 at.% Cr-16 at.% Pt-8 at.% B alloy cap layer, the O / W was improved to -26.1 dB. From these results, in the case of a Co-16 at.% Cr-Pt-8 at.% B alloy, it is possible to achieve -25 dB or less, which is a measure of the O / W index, by setting the Pt concentration to 16 at.% Or less. From this viewpoint, the upper limit of the Pt concentration is preferably 16 at. Moreover, if Pt was not added, the corrosion resistance reliability decreased, so it was preferable to add Pt at 4 at.% Or more. That is, Co-16 at.% Cr- (4 to 16) at.% Pt-8 at.% B is preferable.

  In the case of a Co-15 at.% Cr-12 at.% Pt-B alloy in which the Cr and Pt concentrations are fixed and the ratio of Co and B is changed, the upper limit of the B addition concentration is 10 at. About% is preferable.

  When the thickness of the cap layer 22 is fixed to 6 nm, the So / Nd of the (63-X) at.% Co-15 at.% Cr-12 at.% Pt-Xat.% B alloy is as described in Example 1. The head was evaluated. As a result of trial manufacture and evaluation of media having X of 2, 4, 8, and 10, So / Nd was 22.7 dB at X = 2, whereas So / Nd was from 2 to 10 when X = 4 to 10. 23 dB or more was obtained. From these results, the concentration of B addition is required to be at least 4 at.% Or more from the viewpoint of increasing reproduction noise. Therefore, Co-15 at.% Cr-12 at.% Pt- (4 to 10) at.% B is preferable.

  The case where the thickness of the cap layer 22 considered to have the largest margin is fixed to 6 nm has been described above, but the thickness of the cap layer is not limited to 6 nm, and optimization according to the composition is possible.

  From these results, when a Co—Cr—Pt—B alloy is used as the cap layer, Co— (12 to 20) at.% Cr— (4 to 16) at.% Pt— (4 to 10) at. When% B alloy was used, there was no problem in the processing of the target, excellent corrosion resistance reliability, small increase in the write track width, and media characteristics in which deterioration of the overwrite performance was not recognized.

In Example 1, instead of 92 mol% (50 at.% Fe-50 at.% Pt) -8 mol% SiO ₂ film as the granular recording layer 20, 90 mol% (50 at.% Co-50 at.% Pt) -10 mol% SiO ₂ film was used. Alternatively, a 90 mol% (40 at.% Co-10 at.% Ni-50 at.% Pt) -10 mol% SiO ₂ film was formed to a thickness of 12 nm. The Ar gas pressure for discharge when forming the granular recording layer 20 was 2 Pa. After forming the granular recording layer 20, a cap layer 22 made of 66 at.% Co-34 at.% Pt alloy or Co-15 at.% Cr-12 at.% Pt-8 at. A protective layer 24 containing silicon as a main component was formed to 3 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere substituted with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 containing fluorine as a main component.

  After confirming the mechanical flying characteristics, the same head as in Example 1 was used, and heating was performed using a semiconductor laser 38 with a wavelength of 785 nm of 100 mW during recording. During reproduction, the semiconductor laser 38 was not used, and the electromagnetic conversion characteristics were measured under the condition that the thin film resistor 58 was energized with 60 mW. As a result, when the cap layer 22 was formed to have a thickness of 4 nm or more, the overwrite characteristics were improved, and a value of −25 dB or less was obtained as shown in FIG. On the other hand, the write track width increased as the cap layer 22 increased from 4 nm to 10 nm. FIG. 12 shows the relationship between the write track width normalized by the geometric track width and the cap layer thickness when a Co-15 at.% Cr-12 at.% Pt-8 at.% B alloy is used as the cap layer 22. . This tendency did not depend on the material of the cap layer. From these results, it is clear that the thickness of the cap layer needs to be at least about 4 nm, but considering the widening of the track width, it should be formed to about 6 nm to 8 nm.

[Comparative Example 3]
After forming the soft magnetic underlayer 143 in Example 8 above, the substrate temperature was heated to 280 ° C. on the soft magnetic underlayer 143 without exposing Ar gas containing 1 vol.% Oxygen for 5 seconds. Instead of forming a Ti-6 wt.% Al-4 wt.% V alloy film as the orientation control and low thermal conduction intermediate layer 18, a 10 nm Ti film was formed as the crystal orientation control intermediate layer. In this other process, after forming the granular recording layer 20 under the same conditions as in Example 8, a cap layer 22 made of a Co-15 at.% Cr-12 at.% Pt-8 at.% B alloy is formed from 3 nm to 10 nm. A protective layer 24 containing nitrogen or hydrogen and containing carbon as a main component was formed to a thickness of 3 nm. Furthermore, after maintaining at 300 ° C. for 1 hour in an inert atmosphere substituted with nitrogen, the pressure was returned to atmospheric pressure to form a lubricating layer 26 containing fluorine as a main component.

  These magnetic recording media are evaluated using the evaluation conditions described in Example 1, that is, 100 mW of semiconductor laser 38 having a wavelength of 785 nm is heated during recording, and 60 mW is applied to thin film resistor 58 without using semiconductor laser 38 during reproduction. The electromagnetic conversion characteristics were evaluated under the conditions. As a result, as shown in FIG. 13, the O / W deteriorated from 4 dB to 5 dB compared to Example 8 in any cap layer thickness sample.

On the other hand, the power consumption of the semiconductor laser 38 having a wavelength of 785 nm was increased to 110 mW during recording, and the electromagnetic conversion characteristics were evaluated under the condition that 60 mW was passed through the thin film resistor 58 without using the semiconductor laser 38 during reproduction. Thus, an O / W characteristic comparable to that of Example 8 was obtained. From these results, the thermal conductivity of bulk Ti is 17 W / (m · K), whereas the thermal conductivity of Ti—Al—V alloy is 7.5 W / (m · K), If the thermal conductivity of the orientation control and low thermal conductivity intermediate layer is less than half of Ti, the power consumption during recording for obtaining the same O / W characteristics can be reduced, and the alloy type used for the granular layer is ( 50 at.% Fe-50 at.% Pt) -8 mol% SiO _{2 as} well as (50 at.% Co-50 at.% Pt) -10 mol% SiO ₂ and (40 at.% Co-10 at.% Ni-50 at.% It has been clarified that even Pt) -10 mol% SiO ₂ can be realized.

  The tilted magnetic recording medium of the present invention can be used as a heat-assisted magnetic recording medium.

1 is a cross-sectional configuration diagram of a magnetic recording medium according to the present invention. The conceptual diagram of a heat assistance record. The figure which shows the relationship between an overwrite characteristic and the thickness of a cap layer. The figure which shows the relationship between the write track width normalized by the geometric track width, and the thickness of the cap layer. The cross-sectional block diagram of the sample for measuring an average crystal grain diameter. 1 is a cross-sectional configuration diagram of a magnetic recording medium according to the present invention. 1 is a cross-sectional configuration diagram of a magnetic recording medium according to the present invention. The figure which shows the granular recording layer composition dependence of an overwrite characteristic. The figure which shows the composition dependence of the granular recording layer of So / Nd. 1 is a cross-sectional configuration diagram of a magnetic recording medium according to the present invention. The figure which shows the relationship between an overwrite characteristic and the thickness of a cap layer. The figure which shows the relationship between the write track width normalized by the geometric track width, and the thickness of the cap layer. The figure which shows the relationship between the overwrite characteristic at the time of changing the power consumption of a semiconductor laser, and the thickness of a cap layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Substrate 12 ... Adhesive layer 14 ... Soft magnetic underlayer 141 ... Soft magnetic underlayer 142 ... Nonmagnetic layer 143 ... Soft magnetic underlayer 16 ... Oxide intermediate layer 161 ... Oxide intermediate layer 17 ... Nonmagnetic intermediate layer 18 ... Crystal orientation control and low thermal conductivity intermediate layer 19 ... crystal orientation control layer 20 ... granular recording layer 22 ... cap layer 24 ... protective layer 26 ... lubricating layer 30 ... magnetic recording medium 32 ... slider 34 ... for generating near-field light Scatterer 36 ... magnetic pole 38 ... semiconductor laser 40 ... waveguide core 42 ... waveguide cladding 44 ... magnetic field generating thin film coil 46 ... main magnetic pole 48 ... outflow end 50, 51 ... magnetic pole 52 ... auxiliary magnetic pole 54 ... magnetic reproduction Element 56 ... Shield 58 ... Thin film resistor

Claims (8)

A first soft magnetic layer formed directly or via an adhesive layer on a rigid substrate;
A second soft magnetic layer formed on the first soft magnetic layer via a nonmagnetic intermediate layer;
An intermediate layer made of an oxide formed on the second soft magnetic layer;
Crystal orientation control and low thermal conductivity intermediate layer formed on the intermediate layer,
Granular recording layer mainly composed of composed Fe-Pt alloy composition formed in said crystal orientation-control and low thermal conducting intermediate layer, take the L1 ₀ structure at the stage of progress in ordering is expected When,
A cap layer made of an Fe-Pt alloy or a Co-Cr-Pt-B alloy formed on the granular recording layer;
A magnetic recording medium for tilt recording, comprising a protective layer formed on the cap layer.   2. The magnetic recording medium for inclined recording according to claim 1, wherein an intermediate layer made of a nonmagnetic Ni-based alloy is provided in place of the intermediate layer made of oxide.   2. The magnetic recording medium for tilt recording according to claim 1, wherein the granular recording layer mainly composed of the Fe-Pt alloy contains Cu.   2. The magnetic recording medium for tilt recording according to claim 1, wherein the crystal orientation control and low thermal conductive intermediate layer is made of a Ti-Al-V alloy.   2. The magnetic recording medium for tilt recording according to claim 1, wherein the crystal orientation control and low thermal conductivity intermediate layer is made of Hastelloy C alloy.   2. The magnetic recording medium for tilt recording according to claim 1, wherein a crystal orientation control layer made of Ru is provided between the crystal orientation control and low thermal conduction intermediate layer and the granular recording layer mainly composed of the Fe-Pt alloy. A magnetic recording medium for inclined recording, characterized in that it is formed. After forming a soft magnetic layer on a rigid substrate via an adhesive layer or directly on the substrate, and forming a soft magnetic layer on the soft magnetic layer via a nonmagnetic intermediate layer, an intermediate layer made of oxide, crystal orientation sex control and low thermal conducting intermediate layer, the granular recording layer mainly composed of composed Co-Pt alloy composition is expected to take an L1 ₀ structure at the stage of progress in ordering, Co-Pt alloy or Co- A magnetic recording medium for tilt recording, wherein a cap layer made of a Cr-Pt-B alloy, a protective layer, and a lubricating layer are formed in this order. A substrate in which a first soft magnetic layer is formed directly or via an adhesive layer on a rigid substrate, and a second soft magnetic layer is formed on the first soft magnetic layer via a nonmagnetic intermediate layer is placed in the atmosphere. It is expected to have an L1 ₀ structure when the substrate is heated after the substrate is evacuated by another vacuum process, and then the intermediate layer made of oxide, the crystal orientation control and low thermal conductive intermediate layer, and the ordering progresses. A granular recording layer mainly composed of Fe—Pt alloy or Co—Pt alloy composed of a composition, a cap layer made of Fe—Pt alloy, Co—Pt alloy or Co—Cr—Pt—B alloy, and a protective layer. A method of manufacturing a magnetic recording medium for tilt recording, wherein after the formation, heat treatment is performed, and then a lubricating layer is formed.

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