JPH03108121A - Magnetic recording medium and magnetic recordor - Google Patents

Abstract

PURPOSE:To improve sliding resistance, corrosion resistance and reliability and to realize high-density recording by forming a protective cover layer comprising at least three kinds of specified elements. CONSTITUTION:The protective cover layer on the magnetic layer consists of at least three elements: at least one element selected from a first group of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, at least one element selected from a second group of Y, Mg, Ca, Sc, Fe, Co, Ni, Al, Si, Ru, Rh, Pd, Os, Ir, Pt, Mn, Cu, and Ag, and at least one element selected from a third group of C, N, O, and B. By providing a lubricating layer having at least one adsorptive end group on the protective cover layer, sliding resistance and corrosion resistance of the medium can be improved. The total amt. of elements of the third group is 1 - 99atm.%, and more preferably 20 - 90atm.% of the total amt. of elements of the first group. The total amt. of elements of the second group is 0.1 - 20wt.%, more preferably 0.2 - 10wt.% of the total amt. of other elements.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a magnetic recording medium and a magnetic storage device used in flexible magnetic disk devices, drum-type magnetic storage devices, tape magnetic storage devices, card-type magnetic storage devices, rigid magnetic disk devices, and the like. [Prior Art] In order to cope with the increase in the density of magnetic recording, research and development is underway on magnetic recording media that have thin magnetic layers such as iron oxide thin films, iron nitride thin films, and magnetic alloy thin films as recording layers. These thin film media are deposited on non-magnetic substrates by sputtering, vacuum evaporation,
It is often formed by a method such as a plating method or an ion blating method. These materials are suitable for high recording density because of their small film thickness, large coercive force, and large magnetization. However, magnetic recording media using the above-mentioned magnetic thin film have the disadvantage that they are easily damaged by sliding of the magnetic head and have poor durability. Magnetic recording media used as magnetic files require a particularly high level of reliability. Overcoming the above problems is extremely important in realizing high recording density. In conventional magnetic recording media using continuous thin films, in order to solve the above problems, a method of forming a C-based protective coating layer on the magnetic film (Japanese Patent Laid-Open No. 61-54017, Japanese Patent Laid-Open No. 61-5
4019), a method of further forming an organic liquid lubricant on a C-based protective coating layer (JP-A-61-96512), a method of forming a WC protective coating layer (JP-A-49-2)
0081, JP-A-53-21901, JP-A-53-21902), S x g Z r
r Hf eMethod of forming a nitride or carbide protective coating layer of Ti, Ta, Nb, W (U.S. Pat. No. Re, 3)
2464), oxides of Zr, Ti, Ta, Hf,
A method of forming a protective coating layer of nitride, carbide, or boride (Japanese Unexamined Patent Publication No. 63-66722) has been proposed. [Problem to be Solved by the Invention 1] However, according to the studies of the present inventors, when a C-based protective coating layer is used, the hardness of the protective coating layer is low;
Due to the fact that carbon is easily oxidized and the adhesion of liquid lubricants is poor, the protective coating layer is
It has not yet been possible to sufficiently guarantee the durability of the magnetic recording medium when the thickness is reduced to about nm or less. Also, add WC to the protective solution
When used as uiy, S i , '-Z r ,
Hf, Ti, Ta. When Nb and W nitrides or carbides are used as the protective liquid rIiWJ, the hardness of the protective coating layer is similar to that of the C-based protective coating.
Although it is higher than IIM, the coefficient of friction between the magnetic head and the protective coating is high, the adhesion between the protective liquid RII layer and the magnetic M is small, and the material itself is relatively brittle, so the magnetic recording medium may crack. Problems include that they are prone to rapid damage such as peeling, that they have insufficient sliding resistance when vibrations are applied to the device, and that their protective corrosion resistance is insufficient. The present invention has been made in view of the above points, and is based on a magnetic layer made of metal, oxide, nitride, or the like. By forming a protective coating layer that has excellent adhesion with the magnetic layer, high hardness, high toughness, and low coefficient of friction, and has good adhesion to various types of adsorbent lubricants such as liquids and solids, it has excellent sliding resistance. sex,
The purpose of the present invention is to provide a magnetic recording medium that has excellent corrosion resistance and is suitable for high-density recording, and a highly reliable large-capacity magnetic storage device.

[Means for Solving the Problems 1] In order to achieve the above object, the present invention provides at least one protective coating layer on the magnetic layer, and the protective coating layer is made of Ti, Z
r, Hf, V, Nb, Ta, Cr. At least one element selected from the first group consisting of Mo and W, and Y, Mg, Ca, Sc, and Fe. Co, Ni, AI, Si, Ru, Rh, Pd, Os, I
r, Pt, Mn, Cu, and at least one element selected from the second group consisting of Ag; It is made of at least one element selected from the third group consisting of B. It is further preferable to provide a lubricant layer having at least one adsorbent end group on the protective coating layer, since this can significantly improve sliding resistance and corrosion resistance. The total content of the elements in the third group is set to be at least 99at% fat%, more preferably at least 20at% and not more than 90at%, with respect to the total content of the elements in the first group. The total amount of elements in the group is 0.1 wt% or more and 20 wt% or less, more preferably 0.2 wt% or more and 1 or more 1 material with different bacterial composition, based on the total amount of other elements. It is particularly desirable to stack them to form a protective coating layer, as this further improves corrosion resistance and sliding resistance. The protective coating layer contains W or M o , or both of the elements of the first group, further contains CO of the elements of the second group, and further contains the third group of elements.
It is particularly desirable to include at least C among the elements of the group. Furthermore, the thickness of the protective coating layer is set to 5 nm or more and 60 nm.
The thickness is more preferably 5 nm or more and 40 nm or less, and even more preferably 10 nm or more and 30 nm or less, as this is particularly desirable since it is possible to maintain high sliding resistance and corrosion resistance and also improve recording and reproducing characteristics. [Action] The above effect is due to the following action. Ti, Zr, Hf, V,
The first group of carbides, nitrides, oxides, and borides consisting of Nb, Ta, Cr, Mo, and W generally have high melting points;
Since it exhibits high hardness, it can in principle be used as a thin film protective coating layer for magnetic recording media. However, as a result of examining the sliding resistance of magnetic recording media formed with protective coating layers of carbides, nitrides, oxides, and borides of the elements in the first group, it was found that these magnetic recording media do not have sufficient durability. It became clear that he did not show any gender. this is. Because the protective liquid yIN is brittle and has low adhesion to the magnetic layer,
This is because when an external mechanical force is applied due to the sliding of the magnetic head, cracks occur in the protective coating layer and at the interface between the magnetic layer and the protective coating layer, easily resulting in peeling and destruction. Furthermore, since the protective coating layer has poor adhesion to the liquid lubricant, it has a large coefficient of friction when the magnetic head slides, and there is a problem in that it tends to promote destruction of the magnetic recording medium. On the other hand, according to the studies of the present inventors, an alloy consisting of at least one element selected from the elements of the first group and at least one element selected from the elements of the second group. Carbides, nitrides, oxides. When a boride, carbonitride, oxycarbide, oxynitride, oxyboride, borocarbide, or boronitride is used as a protective coating layer of a magnetic recording medium, the protective coating layer contains extremely fine crystal grains of about 15 nm or less. Or, in typical cases, it becomes amorphous. As a result, the dense protective wave iI layer with few defects uniformly covers the magnetic layer and has good adhesion, so that sliding resistance and corrosion resistance can be improved at the same time. In addition, fine crystal grains or amorphous materials have many unsaturated atoms on one surface, so they have the advantage of good adhesion to liquid lubricants. In this case, the lubricant that can be used is C or Si.
and compounds with adsorbent substituents. In particular, fluoroalkyl polyethers containing a terminal group endowed with an anchor function are more preferred. As such a lubricant, for example, Fomb manufactured by Montegisson
1in Z DIAC, Fomblin Z
DEAL, Fomblin Z DOL, Krytox 157FS manufactured by DuPont, compounds described in European Patent Publication (EP 0165650A2), etc. can be used. Furthermore, by laminating a material with excellent corrosion resistance and a material with excellent sliding resistance, or by laminating a material with excellent sliding resistance, a material with excellent corrosion resistance, and a material with excellent adhesion, a protective coating with a multilayer structure is created. This is particularly desirable since it allows the advantages of the individual layers to be exploited. As mentioned above, the protective coating layer is made of Ti, Zr, and Hf. At least one element selected from the first group consisting of V, Nb, Ta, Cr, Mo, and W, and Y, Mg*Ca
r S c t F e + Co p N ig
A 1 g S x TRu, Rh, Pd, Os, I
Formed with at least one element selected from the second group consisting of r, Pt, Mn, Cu, and Ag and at least one element selected from the third group consisting of C, N, ○, and B. It has become clear that by doing so, a magnetic recording medium with excellent properties can be obtained. The composition of the protective coating layer will be explained in more detail. FIG. 1 shows the basic structure of the magnetic recording medium of the present invention. N
Al-M plated with iP and having a diameter of 130 mm with unevenness of 10 nm in center line average surface roughness in the circumferential direction.
A Cr non-magnetic base layer [12,12', 70 nm thick Co, 350 nm thick Cr non-magnetic base] was deposited on the g alloy substrate 11 by RF magnetron sputtering at a substrate temperature of 100° C., an argon gas pressure of 15 mT-orr, and an input power of I W/aI. (1+5Nio,
A 1sZro+05 magnetic layer 13.13' was formed. Then, (WalsC:o,,,), -XCX protected [
514,14' to DC? A 30 nm thick perfluoroalkyl polyether lubricant layer having an adsorbent ester group at the end was formed using the gnetron scattering method at a substrate temperature of 100°C, an argon gas pressure of 10 mTorr, and an input power of 5 W/a+t. And so. The wear resistance of the disks obtained as described above was evaluated. For evaluation, a sapphire spherical slider with a curvature of 30 mm was pressed against the magnetic disk surface with a load of 10 gf.
A method was adopted in which the magnetic disk was rotated at a relative speed of 10 m/s with respect to the slider, and tin produced on the surface of the magnetic disk after 3600 sliding movements was measured. C fat% or more 99
When adding at% or less, gold mW a , s Co o
3 or C alone, the wear rate was reduced by more than half. Figure 2 shows the tin content in relation to the C content. It can be seen that when C is contained at 20 at % or more, tin becomes significantly smaller, and when C is contained at 90 at % or more, tin becomes larger again. That is, it is more desirable that the C content be 20 at % or more and 90 at % or less, and it is particularly desirable that the C content be 40 aL % or more and 70 at % or less, in which tin is almost the atmosphere. Y, Mg, Ca, Sc, Fe, Co, Ni, AI, Si
, Ru, Rh, Pd, Os, Ir, Pt. At least one element selected from the second group consisting of Mn, Cu, and Ag is added at a ratio of 0.0% to the total acid content of other elements.
By adding 1 wt% or more, the crystal grains became finer, the film structure became more uniform, and the corrosion resistance and sliding resistance were improved by more than twice. Figure 3 shows a similar evaluation in which a perfluoroalkyl polyether lubricant having an adsorptive polar group containing a benzene ring at the end was attached (w-, s-X/2M On,
s4/2CoX) o, *Co, s It was carried out on the protective coating layer, and the time until scratches appear due to sliding is C
It is shown relative to the o content. When 0.1 wt% or more of Co is contained, the sliding resistance can be improved by more than twice that of when no Co is contained at all. When CO is less than 0.1 wt%, the effect of improving sliding resistance is small. Adding more than 20 wt% is not preferable because the hardness decreases and the abrasion resistance also deteriorates. A content of 0°2 wt% or more and 10 wt% or less is particularly desirable because the effect of grain refinement is remarkable and at the same time, the adhesion of lubricants having adsorbent polar groups can be improved, so that the sliding resistance is improved by 5 times or more. The thickness of the protective coating layer is preferably 5 nm or more and 60 nm or less. This is because a protective coating layer with a thickness of less than 5 nm can make a sufficient contribution to improving the durability of a magnetic recording medium, whereas a protective coating layer with a thickness of more than 60 nm can reduce the distance between the magnetic layer and the magnetic head. This is because the separation becomes unnecessary, leading to a deterioration in recording and reproducing characteristics. In order to improve the recording and reproducing characteristics and maintain practical durability, it is more desirable that the film thickness of the protective liquid yIN be 5 nm or more and 40 nm or less, and more preferably 10 nm or more and 30 nm or less.

【Example】

(Example 1) FIG. 1 is a block diagram of a magnetic recording medium according to Example 1 of the present invention. In Fig. 1, 11 is tempered glass. Non-magnetic substrate such as crystallized glass, plastic, ceramics, surface glass coated ceramics, NLP plating A1 alloy, etc. 12.12' is Cr, Mo. Metal underlayer such as W, Cr-Ti, Cr-8i, Cr-W, 13.13' is Go-Ni, Co-Ni-Zr, Co
-Magnetic layer of Cr, Co-Cr-Pt, etc., 14.14' is Ti, Zr, Hf, V, Nb. At least one element selected from the first group consisting of Ta, Cr, Mo, and W, and Y, Mg, and Ca. Sc, Fe, Co, Ni, Al, Si, Ru, Rh, P
At least one element selected from the second group consisting of d, ○s, Ir, Pt, Mn, Cu, and Ag, and C, N,
0. The protective coating layer is composed of at least one element selected from the third group consisting of B. It is preferable to further provide an adsorbent organic lubricant layer thereon, since this significantly improves the sliding resistance. A 130 mmφ Al- plated with NiP and provided with unevenness of 10 nm in the center line average surface roughness in the circumferential direction on the surface.
A Cr film with a thickness of 300 nm and a film thickness of 70 nm were formed on a Mg alloy substrate by RF magnetron sputtering at a substrate temperature of 100°C, an argon gas pressure of 15 mTorr, and an input power of I W/aJ.
After forming 2° of Cool, Ni, g, and sZr, a protective coating layer shown in Table 1 was formed by DC magnetron sputtering at a substrate temperature of 100°C and an argon gas pressure of 10 m.
Torr and an input power of 5 W/d to form a 30 nm thick layer, and a 4 nm perfluoroalkyl polyether lubricating layer having an ester group at the end to form a magnetic disk. An attempt was made to remove the lubricant by immersing the magnetic disk in Freon, but the lubricant was strongly adsorbed and the adsorbed lubricant could not be removed. Table 1 shows the magnetic properties of a sapphire spherical slider with a curvature of 30 mm pressed onto the magnetic disk with a load of 10 gf, and the magnetic disk rotated at a relative speed of 10 m/s to the slider for 3,600 sliding movements. This paper presents the results of evaluating the sliding resistance of magnetic disks based on tin particles formed on the disk surface. In this way, the magnetic disk of this example is 2 times larger than that of the comparative example.
It shows more than double the strength, especially W. No scratches were observed on the protective coating layer containing both Mo, W, and MO after sliding. Also, in sample number 3, Y was used instead of CO. Mg, Ca, Sc, Fe, Ni, AI, Si, Ru, R
h, Pd, Os, Ir, Pt, Mn, Cu. Similar effects were obtained when at least one of Ag was used. Here, the protective coating layer was formed using a carbide alloy target, but a metal alloy target was used to coat Aβ with C, H, .
Sputtering may be performed in a mixed gas containing a hydrocarbon gas such as CH. Table 1 (Example 2) Next, another example using the magnetic disk having the structure shown in FIG. 1 will be described. A 5 mmφ At-Mg alloy substrate was coated with RF magnetron sputtering at a substrate temperature of 150'C and an argon gas pressure of 1.
0 mTorr, input power 3 W/d, 250 nm thick Cr, 70 nm thick co, #, Crg"i, Pt1
l#, , was formed. Thereafter, the protective coating layer shown in Table 2 was formed by reactive sputtering using an RF magnetron at a substrate temperature of 100°C, a mixed gas of 50vo 1% argon gas and 50vo 1% nitrogen gas at a gas pressure of 10 mTorr and an input power of 2 W/aJ. So 2
A perfluoroalkyl polyether lubricant layer having a thickness of 0 nm and an OH group at the end was formed to a thickness of 5 nm to form a magnetic disk. Here, the magnetic disk is immersed in Freon,
An attempt was made to remove the lubricant, but the lubricant was strongly adsorbed, and the adsorbed lubricant could not be removed. A sapphire spherical actuator with a curvature of 30 mm was pressed onto this magnetic disk with a load of 10 gf, and an amplitude of 500 μm was applied.
The sliding resistance of the magnetic disk was evaluated by checking the tin on the surface of the magnetic disk after performing reciprocating motion 30 times per second for 1 nm. As shown in Table 2, the tin content of the magnetic disk of this example was much smaller than that of the comparative example, and showed good wear resistance. In particular, when both Zr and Nb were included, and when W was included, no scratches were observed after sliding. In forming the protective liquid yIWI in Table 2, 1% of nitrogen was mixed with Ar, but 10 to 100 vol of nitrogen was added.
Similar results were obtained for %. Similar results were also obtained when the target material itself was used as a nitriding target. Using the same alloy as in the example shown in Table 2, 0.1 to 50vo 1% oxygen was added to a mixed gas of Ar and nitrogen.
Oxynitride was formed by sputtering in a mixed gas containing I impact resistance was further improved by more than twice, and particularly high sliding resistance was obtained. (Embodiment 3) Next, still another embodiment using the magnetic disk having the structure shown in FIG. 1 will be described. Al plated with NiP and having an unevenness of 10 nm in center line average surface roughness in the circumferential direction on the surface.
- A Cr film with a thickness of 250 nm was formed on a Mg alloy substrate by RF magnetron sputtering at a substrate temperature of 150°C, an argon gas pressure of 10 mTorr, and an input power of 3 W/Ci, a film thickness of 70 nm.
nm of G o, , zCr, , . Ta0. . , and then the protective coating layer shown in Table 3 was formed by reactive sputtering using an RF magnetron at a substrate temperature of 100° C. and an argon gas of 50vo 1%. Oxygen gas 50vo 1% mixed gas at gas pressure 10mTo
A magnetic disk was prepared by forming a 20 nm thick perfluoroalkyl polyether lubricant layer having an adsorption group containing a benzene ring or an NH2 group at the end with an input power of 2 W/d. An attempt was made to remove the lubricant by immersing the magnetic disk in Freon, but the lubricant was strongly adsorbed and the adsorbed lubricant could not be removed. Table 3 A sapphire spherical slider with a curvature of 30 mm was pressed onto this magnetic disk with a load of 10 gf, and the magnetic disk was rotated at a relative speed of 10 m/s to the slider, resulting in a sliding speed of 36
The sliding resistance of the magnetic disk was evaluated based on the tin particles generated on the surface of the magnetic disk at the time of 00 cycles. As shown in Table 3, the tin content of the magnetic disk of this example was much smaller than that of the comparative example, and showed good wear resistance. In particular, when both Zr and Nb were included, no scratches were observed after sliding. mata, choleranoprotective [1ttc, Rh, Si
It also has higher adhesion than conventional protective coating layers such as 02.
Even in a scratch test with a diamond needle, there was almost no peeling. (Embodiment 4) Next, another embodiment using the magnetic disk having the structure shown in FIG. 1 will be described. 89m plated with NiP and chemically etched on its surface to create unevenness with a center line average surface roughness of 5nm.
mφ tempered glass substrate by DC magnetron sputtering at a substrate temperature of 100°C and an argon gas pressure of 10 mTorr.
r, Cr with a film thickness of 250 nm at input power IW/d, Cos with a film thickness of 60 nm,..., N10138 Z r On@
After forming 5Cr010G, a protective coating layer shown in Table 4 was formed to a thickness of 20 nm using a reactive sputtering method using an RF magnetron at a substrate temperature of 150'C, an argon gas pressure of 2 mTorr, and an input power of 5 W/aJ. A magnetic disk was prepared by providing a perfluoroalkyl polyether lubricant layer with a thickness of 7 nm having an adsorbent polar group. Here, an attempt was made to remove the lubricant by immersing the magnetic disk in Freon, but the lubricant was strongly adsorbed and the adsorbed lubricant could not be removed. Table 4 A sapphire spherical slider with a curvature of 30 mm was pressed onto this magnetic disk with a load of 10 gf, and the magnetic disk was rotated at a relative speed of 10 m/s to the slider, resulting in a sliding distance of 3600 mm.
The sliding resistance of the magnetic disk was evaluated based on the tin produced on the surface of the magnetic disk during rotation. As shown in Table 4, the tin content of the magnetic disk of this example was much smaller than that of the comparative example, and showed good wear resistance. In particular, when W and Mo were included, no scratches were observed after sliding. (Embodiment 5) Next, another embodiment using the magnetic disk having the structure shown in FIG. 1 will be described. A 130 mmφ Al- plated NiP plated with unevenness of 10 nm in center line average surface roughness in the circumferential direction.
7. A Cr film with a thickness of 250 nm and a Coo film with a film thickness of 50 nm were formed on an Mg alloy substrate by RF magnetron sputtering at a substrate temperature of 100° C., an argon gas pressure of 5 mTorr, and an input power of 3 W/aJ. c rollp t. , 1S 10+
. After forming No. 2, a protective coating layer shown in Table 5 was formed. Sample numbers 33 to 37 were processed using a DC magnetron sputtering method using a carbide alloy target at a substrate temperature of 100°C, an argon gas pressure of 10m orr, and an input power of 5 W/aJ.
A magnetic disk was formed with a thickness of 0 nm. Sample numbers 38 to 41 were made by reactive sputtering using an RF magnetron, with a substrate temperature of 100°C and argon gas of 50°C.
A magnetic disk was formed by using a mixed gas of 1% VO and 1% nitrogen gas at a gas pressure of 10 mTorr and an input power of 5 W/al to form a magnetic disk. Sample numbers 42 to 44 were made by reactive sputtering using an RF magnetron at a substrate temperature of 100'C and an argon gas of 5.
A magnetic disk was formed with a mixed gas of 0vo 1% and oxygen gas of 50vo 1% at a gas pressure of 10 mTorr and an input power of 5 W/d to a thickness of 30 nm. Sample No. 45 or 647 was formed to a thickness of 30 nm by RF magnetron sputtering using a boride alloy target at a substrate temperature of 100° C., an argon gas pressure of IQ mTorr, and an input power of 5 W/d to form a magnetic disk. A sapphire spherical slider with a curvature of 30 mm was pressed onto this magnetic disk with a load of 10 gf, and the slider was made to reciprocate 30 times per second with an amplitude of 500 Itm. As shown in Table 5, the friction coefficient of the magnetic disk of this example was much lower than that of the comparative example, indicating good sliding resistance. (Example 6) Yet another example will be described. 50 plated with NiP and chemically etched on its surface to create unevenness with a center line average surface roughness of 10 nm.
The substrate temperature was 100°C and the argon gas pressure was 5 mTorr by RF magnetron sputtering on a mmφ tempered glass substrate.
, Cr with a film thickness of 250 nm at an input power of 3 W/cd,...
T io,z, Coo with a film thickness of 50 nm, Cr, 1
．． After forming P to, □2, two or three layers of 10 nm each of the materials shown in Example 5 were laminated under the same conditions as in Example 5 to form the protective coating layer shown in Table 6, and the benzene ring was removed. A magnetic disk was prepared by providing a perfluoroalkyl polyether lubricant layer having a thickness of 5 nm and having an adsorptive polar group. An attempt was made to remove the lubricant by immersing the magnetic disk in Freon, but the lubricant was strongly adsorbed and the adsorbed lubricant could not be removed. The magnetic disk was subjected to a salt spray test using a 1N NaCl aqueous solution at 50°C for 32 hours to evaluate its corrosion resistance. As shown in Table 6, the saturation magnetization (Ms) reduction rate of the magnetic disk of this example was , which was significantly smaller than that of the comparative example, demonstrating excellent corrosion resistance. Furthermore, in terms of sliding resistance, it was confirmed that the lifespan was more than twice as long. Table 6 (Example 7) Metal-in-gap magnetic head using 2, 4 to 8 magnetic disks of Examples 1 to 6 above and providing CoTaZr, FeAlSi alloy, etc. in the gap part, or N
i Fe, Co Fe, Co TaZr
A magnetic disk device was fabricated by combining a thin film magnetic head with an alloy or the like as the magnetic pole material. The average lifespan of the devices until an error occurred was determined, and in all cases the lifespan was 2 to 10 times longer than that of devices using conventional magnetic disks, and a lack of reliability was obtained. Compared to a magnetic disk device combined with a conventional Mn-Zn ferrite ring head, it has a higher ability to erase unnecessary information in the track width direction.
The magnetic disk device according to the present invention has a wide phase margin and can increase storage capacity by more than 1.5 times.

【Effect of the invention】

Since the magnetic recording medium provided with the protective coating layer of the present invention has excellent corrosion resistance and abrasion resistance, it is possible to obtain a magnetic recording medium and a magnetic storage device that are suitable for high-density recording and have sufficient durability for practical use.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the magnetic disk in Example 1 of the present invention, and FIG. 2 is a diagram showing the relationship between the C composition and the wear resistance of the magnetic disk in the (Wo, 9COG, L) 1-XCX protective coating layer. , Figure 3 is (MO0° to Wo9s-X, -X
to CoX). +, c,, protected r! CO in one layer
It is a figure showing the relationship between composition and sliding resistance. Explanation of symbols 11...Substrate, 12.12'...Nonmagnetic underlayer, 1
3゜13'...Magnetic layer, 14.14'...Protective coating layer Figure 2 C concentration χ 3rd layer Cρ channel JE (vt%)

Claims (1)

[Claims] 1. A magnetic recording medium having at least one protective coating layer on a magnetic layer, in which the protective coating layer is composed of Ti, Zr, Hf.
, V, Nb, Ta, Cr, Mo, and at least one element selected from the first group consisting of W; Y, Mg, Ca,
Sc, Fe, Co, Ni, Al, Si, Ru, Rh, P
d, Os, Ir, Pt, Mn, Cu, Ag
at least one element selected from the group of C, N, O
, and at least one element selected from the third group consisting of B. 2. The magnetic recording medium according to claim 1, wherein a lubricant layer having at least one adsorbent end group is present on the protective coating layer. 3. The magnetic recording medium according to claim 1, wherein the total amount of elements in the third group is 1 at % or more and 99 at % or less with respect to the total amount of elements in the first group. 4. The magnetic recording medium according to claim 1, wherein the total amount of the elements in the third group is from 20 at% to 90 at% with respect to the total amount of the elements in the first group. 5. The magnetic recording medium according to claim 1, wherein the total content of the elements in the third group is 40 at% or more and 70 at% or less with respect to the total content of the elements in the first group. 6. The magnetic recording medium according to claim 1, wherein the total amount of the elements of the second group is 0.1 wt% or more and 20 wt% or less with respect to the total amount of other elements. 7. The magnetic recording medium according to claim 1, wherein the total amount of elements in the second group is 0.2 wt% or more and 10 wt% or less with respect to the total amount of other elements. 8. The magnetic recording medium according to claim 1, wherein the protective coating layer contains at least W or Mo. 9. The magnetic recording medium according to claim 1, wherein the protective coating layer contains at least Co. 10. The magnetic recording medium according to claim 1, wherein the protective coating layer contains at least C. 11. The thickness of the protective coating layer is 5 nm or more6
The magnetic recording medium according to claim 1, which has a particle diameter of 0 nm or less. 12. The magnetic recording medium according to claim 1, wherein the protective coating layer has a thickness of 5 nm or more and 40 nm or less. 13. The magnetic recording medium according to claim 1, wherein the protective coating layer has a thickness of 10 nm or more and 30 nm or less. 14. A magnetic device comprising at least a magnetic recording medium having at least one magnetic recording medium surface according to any one of claims 1 to 13 and a magnetic head containing a metal magnetic alloy as at least a part of the magnetic core. Storage device.