JP2009116986A - Method for manufacturing vertical magnetic recording medium, and magnetic recording/reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a vertical magnetic recording medium, wherein a grain diameter of a vertical magnetic recording layer is fine, vertical alignment of the vertical magnetic recording layer and corrosion resistance of the magnetic recording medium are improved and high density information recording/reproduction is made possible. <P>SOLUTION: In the method for manufacturing the vertical magnetic recording medium 10 which includes, on a nonmagnetic substrate 1, at least a lining layer 2, a base film 4, an intermediate layer 5, and the vertical magnetic recording layer 6 having a granular magnetic layer containing at least an oxide, the surface of the lining layer 2 is irradiated with inert gas ions after the lining layer 2 is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a perpendicular magnetic recording medium and a magnetic recording / reproducing apparatus using the perpendicular magnetic recording medium.

  In recent years, the range of application of magnetic recording devices such as magnetic disk devices, flexible disk devices, and magnetic tape devices has been remarkably increased, and the importance has increased, and the recording density of magnetic recording media used in these devices has increased. Significant improvements are being made. In particular, since the introduction of MR heads and PRML technology, the increase in areal recording density has become even more intense. In recent years, GMR heads, TuMR heads, etc. have also been introduced, and are increasing at a rate of about 100% per year.

  As described above, the magnetic recording medium is required to achieve higher recording density in the future. For this purpose, the magnetic recording layer has a higher coercive force, higher signal-to-noise ratio (S / N ratio), and higher resolution. It is required to be achieved. In the longitudinal magnetic recording method that has been widely used so far, as the linear recording density increases, the adjacent recording magnetic domains in the magnetization transition region dominated the self-demagnetization action that weakens each other's magnetization. In order to avoid this, it is necessary to increase the shape magnetic anisotropy by making the magnetic recording layer thinner and thinner.

  On the other hand, as the film thickness of the magnetic recording layer is reduced, the magnitude of the energy barrier for maintaining the magnetic domain and the magnitude of the thermal energy approach the same level, and the recorded magnetization amount is affected by the temperature. It is said that the phenomenon to be relaxed (thermal fluctuation phenomenon) cannot be ignored, and this determines the limit of the linear recording density.

  Under these circumstances, recently, an AFC (Anti Ferromagnetic Coupling) medium has been proposed as a technique to respond to the improvement of the linear recording density of the longitudinal magnetic recording system, and an effort has been made to avoid the problem of thermal magnetic relaxation, which is a problem in longitudinal magnetic recording. ing.

  In addition, the perpendicular magnetic recording technique is attracting attention as a promising technique for realizing a higher areal recording density in the future. While the conventional longitudinal magnetic recording system magnetizes the medium in the in-plane direction, the perpendicular magnetic recording system is characterized by magnetizing in the direction perpendicular to the medium surface. Accordingly, it is considered that the influence of the self-demagnetization action that hinders the achievement of a high linear recording density in the longitudinal magnetic recording method can be avoided, and it is considered suitable for higher density recording. Further, since a certain magnetic layer thickness can be maintained, it is considered that the influence of thermomagnetic relaxation, which is a problem in longitudinal magnetic recording, is relatively small.

  A perpendicular magnetic recording medium is generally formed on a nonmagnetic substrate in the order of an underlayer, an intermediate layer, a magnetic recording layer, and a protective layer. In many cases, a lubricating layer is applied to the surface after forming a protective layer. In many cases, a magnetic film called a soft magnetic backing layer is provided under the underlayer. The intermediate layer is formed for the purpose of further improving the characteristics of the magnetic recording layer. The underlayer is said to function to control the shape of the magnetic crystal while adjusting the crystal orientation of the intermediate layer and the magnetic recording layer.

  In order to manufacture a perpendicular magnetic recording medium having excellent characteristics, the crystal structure of the magnetic recording layer is important. That is, in a perpendicular magnetic recording medium, the crystal structure of the magnetic recording layer often has a hexagonal close-packed structure (hcp structure), but the (002) crystal plane is parallel to the substrate surface. In other words, it is important that the crystal c-axis [002] axis is arranged in the perpendicular direction with as little disturbance as possible.

As shown in Non-Patent Document 1, S. H. Liou et al. Have proposed a so-called granular magnetic layer in which magnetic crystals are separated by a nonmagnetic phase. The granular magnetic layer has a weak magnetic interaction between the magnetic grains, and the magnetic crystal grains can be miniaturized, so that an extremely low noise magnetic layer can be achieved.
S. H. Liou and C.I. L. Chien, Appl. Phys. Lett. 52 (6), 8 Feb. , 1988

  As described above, the use of the granular magnetic layer makes it possible to record and reproduce information with higher density. However, since the backing layer constituting the perpendicular magnetic recording medium contains many elements that easily cause migration such as Co atoms, it diffuses and corrodes on the surface of the perpendicular magnetic recording medium in a high temperature and high humidity environment. There was a problem of letting.

  The present invention has been made in view of the above circumstances, and provides a method for manufacturing a perpendicular magnetic recording medium, a perpendicular magnetic recording medium, and a magnetic recording / reproducing apparatus that improve the corrosion resistance of a magnetic recording medium and have excellent magnetic recording characteristics. The purpose is to do.

In order to achieve the above object, the present invention is listed below.
(1) A method of manufacturing a perpendicular magnetic recording medium having a perpendicular magnetic recording layer having at least a backing layer, an underlying film, an intermediate layer, and a granular magnetic layer containing at least an oxide on a nonmagnetic substrate, the backing layer And forming a perpendicular magnetic recording medium by irradiating the surface of the backing layer with an inert gas.
(2) The method for manufacturing a perpendicular magnetic recording medium according to (1), wherein the inert gas is at least one gas selected from the group consisting of Ar, He, Xe, and Kr. .
(3) The inert gas is irradiated by any method selected from the group consisting of an ion gun, inductively coupled plasma (ICP), and reactive ion plasma (RIE). (2) A perpendicular magnetic recording medium produced by the production method according to any one of (1) to (3).
(5) A magnetic recording / reproducing apparatus comprising a perpendicular magnetic recording medium and a magnetic head for recording / reproducing information on the perpendicular magnetic recording medium, wherein the perpendicular magnetic recording medium is any one of (1) to (3) A magnetic recording / reproducing apparatus, which is a perpendicular magnetic recording medium manufactured by the manufacturing method according to claim 1.

  ADVANTAGE OF THE INVENTION According to this invention, while improving the corrosion resistance of a magnetic recording medium, the manufacturing method of a perpendicular magnetic recording medium excellent in magnetic recording characteristics, a perpendicular magnetic recording medium, and a magnetic recording / reproducing apparatus can be provided.

First, a perpendicular magnetic recording medium which is an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a perpendicular magnetic recording medium according to this embodiment.
As shown in FIG. 1, the perpendicular magnetic recording medium 10 of the present embodiment includes at least a soft magnetic backing layer (backing layer) 2 on a nonmagnetic substrate 1, an orientation control layer 3 including an underlayer 4 and an intermediate layer 5. The perpendicular magnetic recording layer 6, the protective layer 7, and the lubricant layer 8 are formed and roughly configured. FIG. 1 is for explaining the configuration of the perpendicular magnetic recording medium 10 of the present embodiment. The size, thickness, dimensions, etc. of the respective parts shown in the figure are the actual dimensional relationships of the perpendicular magnetic recording medium 10. May be different. First, each layer of the perpendicular magnetic recording medium 10 will be described in detail below.

<Non-magnetic substrate>
The nonmagnetic substrate 1 is not particularly limited, and Al alloy substrate such as Al-Mg alloy mainly composed of Al, normal soda glass, aluminosilicate glass, amorphous glass, silicon, titanium, Any non-magnetic substrate such as a substrate made of ceramics, sapphire, quartz, or various resins can be used. More preferably, it is a glass substrate such as an Al alloy substrate, crystallized glass, or amorphous glass. When a glass substrate is used as the nonmagnetic substrate 1, a mirror polished substrate, a low Ra substrate having a surface roughness (Ra) of less than 1 (１), and the like are more preferable. In addition, if it is mild, the texture may be contained.

<Soft magnetic backing layer>
The soft magnetic backing layer (backing layer) 2 is a soft magnetic film made of a material having so-called soft magnetic characteristics such as an FeCo alloy, a CoZrNb alloy, a CoTaZr alloy, and the like when recording a signal on a medium. The recording magnetic field is guided, and the perpendicular magnetic recording layer 6 is efficiently applied with the perpendicular component of the recording magnetic field. The soft magnetic underlayer 2 is particularly preferably an amorphous (noncrystalline) structure. By making the soft magnetic backing layer 2 have an amorphous structure, it is possible to prevent the surface roughness (Ra) from increasing, reduce the flying height of the head, and further increase the recording density. Furthermore, the soft magnetic backing layer 2 is not only a single layer, but also an anti-ferromagnetic coupling (AFC) between soft magnetic layers applied by sandwiching an extremely thin nonmagnetic thin film such as Ru between the two layers. You can also The total film thickness of the soft magnetic backing layer 2 is preferably about 20 (nm) to 120 (nm), and can be appropriately determined depending on the balance between the recording / reproducing characteristics and the overwrite (OW) characteristics.

<Orientation control layer>
The orientation control layer 3 is provided on the soft magnetic backing layer 2 and controls the orientation of the film immediately above the orientation control layer 3. Further, the orientation control layer 3 is composed of a plurality of layers, and the orientation control layer 3 of the present embodiment is composed of a base layer 4 and an intermediate layer 5 laminated from the nonmagnetic substrate 1 side.

(Underlayer)
The material of the underlayer 4 is Ta or a metal or alloy (for example, Ni, Ni-Nb, Ni-Ta, Ni-V, Ni-W, Pt) having a face-centered cubic structure (fcc structure) oriented in the (111) plane. Etc.) can be used. Even if the soft magnetic underlayer 2 has a microcrystalline or amorphous structure, the surface roughness (Ra) of the orientation control layer 3 may increase depending on the material and film formation conditions. By forming a nonmagnetic amorphous layer between the backing layer 2 and the orientation control layer 3, the surface roughness (Ra) of the orientation control layer 3 is lowered, and the crystal orientation of the perpendicular magnetic recording layer 6 is improved. Can be improved.

(Middle layer)
The intermediate layer 5 is provided on the base layer 4. As the material of the intermediate layer 5, Ru or Re having a hexagonal close-packed structure (hcp structure) similar to that of the perpendicular magnetic recording layer 6, an alloy thereof, or an oxide thereof can be used. Further, since the intermediate layer 5 functions to control the orientation of the perpendicular magnetic recording layer 6, it is not limited to a material having a hexagonal close-packed structure (hcp structure). Any material that can be controlled can be used.

<Magnetic recording layer>
The perpendicular magnetic recording layer 6 has a granular magnetic layer containing at least an oxide. The perpendicular magnetic recording layer 6 is a layer on which signals are actually recorded. The easy magnetization axis (crystal c axis) is oriented mainly perpendicularly to the nonmagnetic substrate 1. Therefore, finally, the crystal structure and magnetic properties of the perpendicular magnetic recording layer 6 determine recording and reproduction.

The constituent material of the perpendicular magnetic recording layer 6, CoCr, CoCrPt, CoCrPtB, CoCrPtB-X, CoCrPtB-X-Y, CoCrPt-O, CoCrPt-SiO 2, CoCrPt-Cr 2 O 3, CoCrPt-TiO 2, CoCrPt- Examples are Co-based alloy thin films such as ZrO ₂ , CoCrPt—Nb ₂ O ₅ , CoCrPt—Ta ₂ O ₅ , and CoCrPtTiO ₂ . Note that X in the above constituent materials represents Ru, W, or the like, and Y represents Cu, Mg, or the like.
In particular, a magnetic material containing an oxide such as O, SiO ₂ , Cr ₂ O ₃ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and a Co alloy such as CoCrPt as a constituent material of the perpendicular magnetic recording layer 6. In the case of using a layer (oxide magnetic layer), it is preferable that the non-magnetic oxide adopts a granular structure surrounding the ferromagnetic Co crystal grains. Thereby, the magnetic interaction between Co crystal grains is weakened, and noise can be reduced. In the present embodiment, the perpendicular magnetic recording layer 6 is preferably formed by forming a granular magnetic layer including at least one oxide.

<Protective layer>
The protective layer 7 is provided to protect the perpendicular magnetic recording medium 10 from damage due to contact between the magnetic head and the perpendicular magnetic recording medium 10. As a material of the protective layer 7, a carbon film, a SiO ₂ film, or the like is preferable, and a carbon film is particularly preferable.

<Lubricant layer>
The lubricant layer 8 is preferably made of a conventionally known material such as perfluoropolyether, fluorinated alcohol, fluorinated carboxylic acid or the like.

Next, an example of a method for manufacturing the perpendicular magnetic recording medium 10 shown in FIG. 1 will be described.
The method for manufacturing the perpendicular magnetic recording medium 10 shown in FIG. 1 is roughly composed of a substrate cleaning step, a magnetic layer forming step, an inert gas irradiation step, and a protective layer forming step. Hereinafter, each step will be described.

<Substrate cleaning process>
In the manufacturing process of the magnetic disk, the substrate is usually first washed and dried. In this embodiment, it is desirable to perform washing and drying before formation from the viewpoint of ensuring the adhesion of each layer. . In the substrate cleaning step, the method for cleaning the nonmagnetic substrate 1 is not limited to water cleaning, but also includes cleaning by etching (reverse sputtering). Also, the substrate size is not particularly limited.

<Formation process of magnetic layer>
In the magnetic layer forming step, a magnetic layer comprising a soft magnetic backing layer 2, an underlayer 4, an intermediate layer 5, and a perpendicular magnetic recording layer 6 is sequentially stacked on the data recording area of the nonmagnetic substrate 1. .
A DC magnetron sputtering method or an RF sputtering method is usually used for forming the soft magnetic backing layer 2, the underlayer 4, the intermediate layer 5, and the perpendicular magnetic recording layer 6. Further, RF bias, DC bias, pulse DC, pulse DC bias, O ₂ gas, H ₂ O gas, H ₂ gas, and N ₂ gas can be used.
The sputtering gas pressure at the time of film formation can be appropriately determined so that the characteristics are optimized for each layer, and is generally controlled in the range of about 0.1 to 30 (Pa), and the performance of the perpendicular magnetic recording medium 10 is improved. Adjust while watching.

  In order to make the perpendicular magnetic recording layer 6 have a granular structure, it is preferable to increase the film forming gas pressure of the intermediate layer 5 to make the surface of the intermediate layer 5 uneven. Thereby, since the oxide of the magnetic layer including the oxide constituting the perpendicular magnetic recording layer 6 is collected in the concave portion on the surface of the intermediate layer 5, the perpendicular magnetic recording layer 6 has a granular structure. On the other hand, when the film forming gas pressure of the intermediate layer 5 is increased, the crystal orientation of the intermediate layer 5 is deteriorated and the surface roughness may be excessively increased. For this reason, it is preferable to form the intermediate layer 5 sequentially as a two-layer structure of a low gas pressure film-forming layer and a high gas pressure film-forming layer. Thereby, both the maintenance of the orientation of the intermediate layer 5 and the formation of surface irregularities can be achieved.

<Inert gas irradiation process>
In the present embodiment, after the soft magnetic underlayer 2 is formed, the soft magnetic underlayer 2 is irradiated with an inert gas. Since the soft magnetic backing layer 2 contains a large amount of Co, Fe, and the like, it is likely to oxidize and is considered to cause corrosion of the perpendicular magnetic recording medium 10. Therefore, migration of magnetic particles such as Co crystal grains (hereinafter referred to as “magnetic particles”) is suppressed because the movement of the magnetic particles is suppressed by the intrusion of the inert elements into the soft magnetic backing layer 2 by irradiation with the inert gas. Is considered to be suppressed. Further, it is considered that the migration of the magnetic particles is suppressed by removing the active surface of the soft magnetic underlayer 2. Accordingly, it is considered that the soft magnetic backing layer 2 is stabilized and the occurrence of magnetic particle migration or the like is suppressed even in a high temperature and high humidity environment. Furthermore, it is considered that the crystal orientation of the layer formed on the soft magnetic backing layer 2 is improved by removing the oxide on the surface of the soft magnetic backing layer 2.

  As the inert gas, it is preferable to use at least one gas selected from the group consisting of Ar, He, Xe, and Kr. The above elements are preferable because they are chemically stable and have a high effect of suppressing migration of magnetic particles.

As the inert gas irradiation method, it is preferable to use any method selected from the group consisting of an ion gun, an inductively coupled plasma (ICP), and a reactive ion plasma (RIE). It is more preferable to use ICP or RIE in terms of a large amount of irradiation.
Inductively coupled plasma (ICP) is a high-temperature plasma obtained by generating a plasma by applying a high voltage to a gas and generating Joule heat due to an eddy current inside the plasma by a high-frequency variable magnetic field. Since inductively coupled plasma has a high electron density, it is possible to modify the magnetic properties with high efficiency over a wide area magnetic film.
Reactive ion plasma (RIE) is a highly reactive plasma in which a reactive gas such as SF ₆ , CHF ₃ , CF ₄ , CCl ₄ is added to the plasma. For this reason, the modification of the magnetic properties of the magnetic film can be realized with higher efficiency.

<Protective layer formation process>
The protective layer 7 can be formed by sputtering, plasma CVD, or the like, and plasma CVD is particularly preferable. Furthermore, it is possible to use a magnetron plasma CVD method. The film thickness of the protective layer 7 is in the range of 1 to 10 (nm), preferably in the range of 2 to 6 (nm), and more preferably in the range of 2 to 4 (nm).

For the formation of the lubricant layer 8, a conventionally known method such as a dipping method or a spin coating method can be used. The film thickness of the lubricant layer 8 is usually in the range of 1 to 4 (nm).
As described above, the perpendicular magnetic recording medium 10 shown in FIG. 1 can be manufactured.

<Magnetic recording / reproducing device>
Next, a magnetic recording / reproducing apparatus using the perpendicular magnetic recording medium 10 will be described.
FIG. 2 shows an example of a magnetic recording / reproducing apparatus using the perpendicular magnetic recording medium 10. As shown in FIG. 2, the magnetic recording / reproducing apparatus 100 records information on the perpendicular magnetic recording medium 10 having the above-described configuration, a medium driving unit 101 that rotationally drives the perpendicular magnetic recording medium 10, and the perpendicular magnetic recording medium 10. A magnetic head 102 for reproduction, a head drive unit 103 for moving the magnetic head 102 relative to the perpendicular magnetic recording medium 10, and a recording / reproduction signal processing system 104 are provided.

  The recording / reproducing signal processing system 104 can process data input from the outside and send the recording signal to the magnetic head 102, and can process the reproducing signal from the magnetic head 102 and send the data to the outside. It is like that.

  The magnetic head 102 used in the magnetic recording / reproducing apparatus 100 of the present embodiment has not only an MR (Magneto Resistance) element using an anisotropic magnetoresistive effect (AMR) as a reproducing element but also a giant magnetoresistive effect (GMR). A magnetic head suitable for a higher recording density having a GMR element used, a TuMR element using a tunnel effect, or the like can be used.

  As described above, according to the method of manufacturing the perpendicular magnetic recording medium 10 of the present embodiment, the soft magnetic backing layer 2 is irradiated with inert gas ions, so that the corrosion of the soft magnetic backing layer 2 can be reduced. it can. Thereby, the corrosion resistance of the perpendicular magnetic recording medium 10 can be improved.

  Further, by irradiating the soft magnetic backing layer 2 with inert gas ions, a small amount of oxide layer, impurities, etc. on the surface of the soft magnetic backing layer 2 are removed, so that the soft magnetic backing layer 2 is laminated on the soft magnetic backing layer 2. The crystallinity of the underlayer 4, the intermediate layer 5, and the perpendicular magnetic recording layer 6 to be formed can be improved.

  Therefore, according to the method for manufacturing the perpendicular magnetic recording medium 10 of the present embodiment, the perpendicular magnetic recording medium 10 having excellent corrosion resistance and excellent magnetic recording characteristics can be manufactured. In addition, the magnetic recording / reproducing apparatus 100 to which the perpendicular magnetic recording medium 10 manufactured by the manufacturing method of the present embodiment is applied can be provided.

  Further, the perpendicular magnetic recording medium 10 of the present embodiment can be applied to new perpendicular recording media such as ECC media, discrete track media, and pattern media that are expected to further improve recording density in the future.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

(Example)
The vacuum chamber in which the glass substrate for HD was set was evacuated to 1.0 × 10 ⁻⁵ (Pa) or less in advance.
Next, a Co ₂₈ Fe ₄ Zr film was formed as a soft magnetic underlayer on this substrate to a thickness of 50 (nm) by using a sputtering method.

Next, the inert gas plasma was irradiated to the surface of the soft magnetic underlayer using Ar, He, Xe, or Kr. For inert gas plasma irradiation, gas flow rate: 5 (sccm), pressure: 0.014 (Pa), acceleration voltage: 300 (V), current density: 0.4 (mA / cm ² ), treatment Irradiation conditions of time: 5, 15, 25 (sec) were used. Here, perpendicular magnetic recording media processed at Ar plasma processing times of 5, 15, and 25 (sec) were referred to as Examples 1, 2, and 3, respectively. Also, the perpendicular magnetic recording media processed using He, Xe, and Kr as the inert gas plasma were set to Examples 4, 5, and 6 for a processing time of 15 (sec), respectively.

After plasma irradiation with an inert gas, NiFe having a face-centered cubic structure (fcc structure) as an underlayer is formed in an Ar atmosphere at a gas pressure of 0.6 (Pa) so as to have a film thickness of 5 (nm). Filmed.
Next, as an intermediate layer, Ru was deposited in a thickness of 10 (nm) in an Ar atmosphere having a gas pressure of 0.6 (Pa), and then the gas pressure was increased to 10 (Pa) to further deposit 10 (nm).

The perpendicular magnetic recording layer was formed in the order of the main recording layer and the auxiliary recording layer in an Ar atmosphere at a gas pressure of 2 (Pa). As the main recording layer, 90 (Co ₁₂ Cr ₁₈ Pt) -10 (SiO ₂ ) was formed to a thickness of 10 (nm). 90-10 in the above 90 (Co ₁₂ Cr ₁₈ Pt) -10 (SiO ₂ ) represents a molar ratio. Further, the above-mentioned 12, 18, and 3 indicate that Cr is 12 mol%, Pt is 18 mol%, Ru is 3 mol%, and Co is the balance.
Next, a carbon film (C film) was formed as a protective layer, and perfluoropolyether (PFPE) was applied as a lubricant layer to a thickness of 15 (Å) by a dip method.

(Comparative example)
Magnetic recording media were manufactured using the same manufacturing conditions as in Examples 1-6. Here, a perpendicular magnetic recording medium in which the soft magnetic underlayer was not irradiated with plasma of an inert gas was used as Comparative Example 1.

(Evaluation of electromagnetic conversion characteristics)
Each magnetic recording medium manufactured as an example and a comparative example was evaluated for electromagnetic conversion characteristics using a spin stand. Specifically, a perpendicular recording head for recording and a TuMR head for reproduction were used as magnetic heads for evaluation, and SNR values were measured when a 750 kFCI signal was recorded. The measurement results are shown in Table 1.

(Evaluation of crystal structure)
For each magnetic recording medium manufactured as an example and a comparative example, the crystal structure was evaluated using the half value of the rocking curve. Specifically, first, a film formed on the substrate was applied to an X-ray diffractometer, and a crystal plane parallel to the substrate surface was analyzed.
Here, when the sample contains a film having a hexagonal close-packed structure such as an intermediate layer or a magnetic recording layer, a diffraction peak corresponding to the crystal plane is observed. In the case of a perpendicular magnetic recording medium using a Co-based alloy, since the c-axis [002] direction of the hexagonal close-packed structure is oriented perpendicular to the substrate surface, a peak corresponding to the (002) plane is obtained. It will be observed.

Next, when the optical system is swung with respect to the substrate surface while maintaining the Bragg angle diffracting the (002) plane, the diffraction intensity of the (002) crystal plane is plotted against the angle at which the optical system is tilted. A single diffraction peak (called rocking curve) was drawn.
Here, when the (002) crystal plane is aligned very well in parallel with the substrate surface, a sharp rocking curve is obtained. On the other hand, when the orientation of the (002) crystal plane is widely dispersed, a broad rocking curve is obtained.
Therefore, the half-value width Δθ50 of the rocking curve can be used as an index of the quality of the crystal orientation of the perpendicular magnetic recording medium. It can be evaluated that the smaller the value of Δθ50, the better the crystal orientation of the perpendicular magnetic recording medium. The measurement results of Δθ50 are shown in Table 1.

As shown in Table 1, the electromagnetic conversion characteristics (S / N ratio) of Examples 1, 2, and 3 in which Ar plasma irradiation was performed relative to Comparative Example 1 in which the soft magnetic backing layer was not irradiated with plasma of an inert gas. 3 and Examples 4, 5, and 6 in which He, Xe, and Kr plasma irradiations were performed were confirmed to be improved.
Moreover, it has confirmed that the crystal structure (crystal orientation) was improving significantly in Examples 1-6 with respect to the comparative example 1. FIG.

FIG. 1 is a schematic cross-sectional view of a perpendicular magnetic recording medium showing an embodiment of the present invention. FIG. 2 is a perspective view of a magnetic recording / reproducing apparatus showing an embodiment of the present invention.

Explanation of symbols

  1 ... Nonmagnetic substrate, 2 ... Soft magnetic backing layer, 3 ... Orientation control layer, 4 ... Underlayer, 5 ... intermediate layer, 6 ... perpendicular magnetic recording layer, 7 ... Protective layer, 8 ... lubricant layer, 10 ... perpendicular magnetic recording medium, 100 ... magnetic recording / reproducing apparatus, 101 ... medium drive unit, 102 ... magnetic head, 103 ... head Drive unit, 104... Recording / reproducing signal system

Claims (5)

A method of manufacturing a perpendicular magnetic recording medium having a perpendicular magnetic recording layer having a granular magnetic layer including at least a backing layer, an underlayer, an intermediate layer, and at least an oxide on a nonmagnetic substrate,
A method of manufacturing a perpendicular magnetic recording medium, wherein after forming the backing layer, the surface of the backing layer is irradiated with an inert gas.   2. The method for manufacturing a perpendicular magnetic recording medium according to claim 1, wherein the inert gas is at least one gas selected from the group consisting of Ar, He, Xe, and Kr.   The inert gas is irradiated by any method selected from the group consisting of an ion gun, inductively coupled plasma (ICP), and reactive ion plasma (RIE). Method for manufacturing perpendicular magnetic recording medium   The perpendicular magnetic recording medium manufactured by the manufacturing method as described in any one of Claims 1 thru | or 3.   4. A magnetic recording / reproducing apparatus comprising a perpendicular magnetic recording medium and a magnetic head for recording / reproducing information on / from the perpendicular magnetic recording medium, wherein the perpendicular magnetic recording medium is according to claim 1. A magnetic recording / reproducing apparatus, wherein the magnetic recording / reproducing apparatus is a perpendicular magnetic recording medium manufactured by the manufacturing method.

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