JPH06215941A - Magnetic recording medium, target for forming magnetic recording film, and method for forming magnetic recording film - Google Patents

Abstract

(57) [Abstract] [Objective] Improvement of noise characteristics and coercive force of magnetic film for increasing recording density of magnetic recording medium [Structure] Hard magnetic compound having Nd ₂ Fe ₁₄ B type crystal structure as a magnetic recording film To form a magnetic film body having a fine mixed phase structure in which the fine crystal grains are densely dispersed in a matrix made of a soft magnetic compound containing Co as a main component. Its magnetic _{film, T 100-uv R u X} v [T: iron group transition metal elements (Co, Ni or Fe,),
R: rare earth element, X: B, C, u: 0.5-9%,
v: 5 to 25%, T is Co as an essential element, the Co content is 50% or more with respect to the entire T, and R is Pr, Nd, Tb,
One or two or more kinds of Dy are essential elements, the amount of R _{1 in the} whole R is 30% or more, and X is B as an essential element, and X
It is formed by spattering a target having a chemical composition of B occupying 5% or more of the whole] and crystallizing the deposited film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium having improved noise characteristics and high coercive force capable of high density recording, a sputtering target for forming the magnetic recording film, and a magnetic recording film. And a method of forming the same.

[0002]

2. Description of the Related Art In a magnetic recording medium such as a magnetic disk, a magnetic drum, a magnetic sheet, a magnetic tape, etc., the magnetic recording film (magnetic film) is made of CoCr, CoN or the like in order to achieve high density recording.
i, a metal thin film magnetic recording medium formed of a Co-based ferromagnetic alloy such as CoCrNi is predominant. There is an ever-increasing demand for high-density recording in the magnetic recording field, and for this purpose, it is necessary to further improve the characteristics of the magnetic recording film, particularly the noise characteristics (S / N characteristics) and the coercive force. In response to the request, measures such as miniaturization of crystal grains of the magnetic film, isolation of magnetic domains by grain boundary segregation, and increase of coercive force have been made. For example, the magnetic film is formed of CoCrPt alloy in which Pt is added to Co-based alloy. What is decided to do (Japanese Patent Laid-Open No. 1-28380
No. 3), a CoCrTa alloy with Ta added as a magnetic film alloy (JP-A-2-306419), or a CoNiCrB alloy with B added as a magnetic film alloy (JP-A-3-49021). Etc., or a number of proposals have been made regarding control of process conditions in sputtering film formation of magnetic films. However, P
There is a limit to the effect of improving the noise characteristics and coercive force by devising the composition of the magnetic film alloy to which alloy elements such as t, Ta, B, etc. are added, and controlling the film forming conditions therefor. It's hard to do. Moreover, the disadvantage of the increase in manufacturing cost due to the use of expensive elements such as Pt is inevitable, and the control of the process conditions in the sputtering film formation of the magnetic film inevitably complicates the film formation process. It will be.

As another means for improving the coercive force of the magnetic recording film, it is possible to apply a rare earth element having high magnetic anisotropy. In the field of permanent magnets, SmCo ₅ magnets and N
By developing rare earth magnets such as d ₂ Fe ₁₄ B magnets, we have achieved remarkable success in achieving high coercive force. However, since the rare earth element is an element that is very easily oxidized, SmCo ₅ containing a large amount of this (content of the rare earth element: 33% by weight)
Alternatively, Nd ₂ Fe ₁₄ B (the same content: 27% by weight) cannot be directly applied to the magnetic recording film. This is because if an oxide film is formed on the surface of the magnetic film, the function as a magnetic recording film cannot be ensured (in a permanent magnet, the surface is protected by a nickel plated film having a film thickness of about 10 μm or more. , In the magnetic recording film, such a thick protective film cannot be formed from the viewpoint of ensuring an effective distance between the film surface and the magnetic head during recording and reproduction.).

As another method of improving the coercive force by using a rare earth element, it is possible to alloy a rare earth element with a Co type alloy which is a known magnetic film alloy such as CoCr to increase its magnetic anisotropy. For that purpose, the rare earth element must be uniformly solid-dissolved. However, rare earth elements hardly dissolve in Co, and therefore improvement of coercive force due to alloying of rare earth elements cannot be expected.

[0005]

SUMMARY OF THE INVENTION The present invention uses a rare earth element having a high magnetic anisotropy as a constituent element of a magnetic film, and prevents problems associated with the use of the rare earth element, in particular, suppression of oxidative deterioration of the magnetic film surface. It is intended to realize a new magnetic recording medium capable of high density recording surpassing conventional magnetic recording films by dramatically improving S / N characteristics and coercive force while ensuring the corrosion resistance required for is there. Up to now, the film material which has been studied for the improvement of the magnetic film of the magnetic recording medium is C
Including Co-based alloys such as oCr, all of them are film materials having only a hard magnetic phase. This is because in the mixed phase structure in which the hard magnetic phase and the soft magnetic phase are dispersed and mixed, the squareness of the magnetization curve is poor, and it becomes difficult to secure the necessary function as a magnetic recording medium. The conventional wisdom was that only the hard magnetic phase should be used. However, the present inventors have recently been developing in the field of permanent magnets, Exch
ange-spring Magnet model (IEEE TRANSACTIONS ON MAG
NETICS VOL.27 NO.4 JULY 1991 P.3588-3600 "The E
xchange-Spring Magnet A NEW MATERIAL PRINCIPLE FOR
PERMANENT MAGNETS ”) is applied to a magnetic recording medium to form a fine multi-phase structure in which a hard magnetic substance is dispersed in a soft magnetic substance in an extremely fine and dense manner to obtain a good squareness of the magnetization curve required for the magnetic recording medium. In addition to being secured, highly improved noise characteristics and coercive force are obtained as a fine dispersion effect of the hard magnetic compound formed by the addition of a relatively small amount of rare earth element, and it is good for the soft magnetic phase. If corrosion resistance is imparted, even with a multiphase structure in which a hard magnetic phase containing a rare earth element that is easily oxidized is dispersed, the oxidation deterioration of the magnetic film surface can be effectively prevented and prevented, and magnetic recording can be performed. The inventors have come to the finding that they can retain the improved function as a membrane. The present invention has been completed based on such findings.

[0006]

In the magnetic recording medium of the present invention, as a magnetic recording film, fine particles of a hard magnetic compound having an Nd ₂ Fe ₁₄ B type crystal structure are made of a soft magnetic compound containing Co as a main component. It is characterized by having a magnetic film body having a fine mixed phase structure which is densely dispersed in the matrix. The target of the present invention used for the sputtering film formation of the magnetic film of the magnetic recording medium has a chemical composition represented by the following formula [I]. T _100-uv R _u X _v [I] In the formula, T is an iron group transition metal element, R is a rare earth element, and X is
Represents B or C, and u representing the atomic composition ratio is 0.5
~ 9%, v is 5 to 25%, iron group transition metal element T
Contains Co as an essential element, and contains Ni and / or F
When e is allowed to be mixed, and when Ni and / or Fe are mixed, the ratio of Co to the whole T occupies 50% or more, and the rare earth element R is Pr, Nd, Tb, or Dy.
(Hereinafter, “R ₁ element”), one or more elements selected from the group consisting of La, Ce, Y, Sm
And, one or more kinds of other rare earth elements are allowed to be mixed, and when these elements are mixed, the ratio of R ₁ element to the whole R is 30% or more, and the element X is B
Is an essential element, and when C is mixed in this, the ratio of B to the entire X is 5% or more.

[0007]

The magnetic recording film of the present invention has a fine structure in the two-phase mixed phase structure of the hard magnetic phase and the soft magnetic phase.
-As a spring magnet effect, it has a good squareness of the magnetization curve. Nd ₂ F which is a hard magnetic phase in the mixed phase structure
The e ₁₄ B type compound has extremely high magnetic anisotropy, and its fine crystal grains are densely dispersed in the soft magnetic phase, which is an extremely good noise characteristic over conventional CoCr alloy magnetic films. , High coercive force is secured. Nd which is a hard magnetic phase
A compound having a ₂ Fe ₁₄ B type crystal structure (in the present invention, the iron group transition metal element T is mainly Co) has a smaller oxidation tendency than a hard magnetic compound in which the iron group transition metal element T is Fe. . On the other hand, the soft magnetic phase containing Co as a main component (represented by a Co ₃ B compound), which constitutes the matrix of a mixed phase structure, has a large magnetization and a high Curie temperature, and thus gives a large signal as a magnetic recording film. It is possible to take out, and a high S / N ratio can be realized because the hard magnetic phase is dispersed and mixed as fine particles therein. Moreover, this soft magnetic phase has good corrosion resistance. Further, the rare earth element for increasing the coercive force of the magnetic film of the present invention is mostly involved in the formation of the hard magnetic phase and is localized in the film body, and the content of the rare earth element in the entire magnetic film is , SmCo ₅ magnets, etc., the amount is extremely small, the oxidation tendency of the film body is small accordingly, and the hard magnetic phase containing the rare earth element is finely dispersed and mixed in the soft magnetic phase having good corrosion resistance. Therefore, as the encapsulating protection effect by the soft magnetic phase, the oxidation deterioration of the magnetic film is effectively suppressed and prevented, and the functions required for the magnetic recording medium can be stably maintained.

The present invention will be described in detail below. The magnetic recording film of the present invention having a two-phase mixed phase structure in which the hard magnetic phase is dispersed in the matrix of the soft magnetic phase is Exchange-spring.
Due to the Magnet effect, a high degree of coercive force and noise characteristics are secured along with good squareness of the magnetization curve.
It is necessary that the hard magnetic phase has a fine and minutely dispersed structure. The crystal grain size of the hard magnetic phase is preferably about 5
It is 0 nm or less, more preferably 30 nm or less, and the distance between particles is about 70 nm or less, more preferably 50 nm or less. Further, the proportion of the hard magnetic phase in the mixed phase structure is preferably about 3% by volume or more, and more preferably 5% by volume or more, in order to sufficiently exhibit the high coercive force.
However, if the amount is too large, the oxidation tendency of the membrane increases, so the upper limit is preferably about 40% by volume, and more preferably 25% by volume or less.

The composition of components of the magnetic film of the magnetic recording medium of the present invention has the composition ratio represented by the above formula [I] for the sputtering target. The atomic composition ratio u of the rare earth element R is 0.5 to 9%
If the amount is less than 0.5%, the hard magnetic phase (Nd ₂ Fe ₁₄ B
This is because the effect of improving the coercive force, which is manifested as a dispersion effect of the (type compound), is insufficient, while the upper limit is 9%.
Beyond that, due to the overproduction of the hard magnetic phase, Exchange
-It becomes difficult to form a fine and dense multiphase structure for exerting the spring magnet effect, and it is difficult to sufficiently exert the effect of significantly improving noise characteristics and coercive force, and the tendency of the magnetic film to deteriorate due to oxidation increases. This is because it causes the disadvantage of. It is preferably 0.7 to 7%, more preferably 0.8.
~ 5%. For the element X, its atomic composition ratio v
Was set to 5 to 25% because when the amount is less than 5%, the dispersion of the hard magnetic compound particles in the matrix of the soft magnetic phase becomes depopulated and the particle spacing increases.
This is because it is difficult to secure a fine mixed-phase structure for achieving the et effect. On the other hand, the upper limit of 25% is that if it exceeds that, the Nd ₂ Fe ₁₄ B type compound other than the Nd ₂ Fe ₁₄ B-type compound is contained in the soft magnetic phase. This is because the phase precipitates, which causes the magnetic properties to be adversely affected. Preferably, it is 9 to 20%.

Further, an iron group transition metal element T (Co, Ni,
Regarding Fe), Co is an essential element because it is a soft magnetic compound containing Co as a main component (Co ₃ B, which has a large magnetization and a high Curie point and has good corrosion resistance as a matrix of a mixed phase structure). Which is a hard magnetic phase dispersed in the matrix.
_As a compound having a ₂ Fe ₁₄ B-type crystal structure, a compound whose iron group transition metal is mainly Co (hereinafter, referred to as “R ₂ Co ₁₄ B
Is also referred to as a “compound”). That N
The R _{2 Co 14} B compound, which is a d ₂ Fe ₁₄ B type compound, is advantageous in that it has high magnetic anisotropy and excellent corrosion resistance as compared with a compound in which the iron group transition metal element is Fe. . From this point of view, the proportion of Co in the entire iron group transition metal (T) is preferably at least 50%. More preferred is 70% or more, and most preferred is 80% or more.

R ₂ C having Nd ₂ Fe ₁₄ B type crystal structure
_{The o14} B compound may be a compound in which a part of Co is replaced by Fe and Ni. By substituting a part of Co with Fe, the magnetization of the magnetic film is increased, while a part of Co is replaced with N.
By substituting i for the soft magnetic phase and the hard magnetic phase, the effect of enhancing the corrosion resistance can be obtained. However, with respect to Fe, when the amount thereof is large, it causes a decrease in magnetic anisotropy and causes a decrease in the oxidation resistance of the hard magnetic phase. Therefore, Fe with respect to the entire iron group transition metal (T) is
The amount is preferably 50% or less, more preferably 30
% Or less, more preferably 20% or less. As the amount of Ni increases, the magnetization and Curie temperature of both the soft magnetic phase and the hard magnetic phase decrease, and the magnetic anisotropy of the hard magnetic phase decreases. The upper limit is preferably 30% of the total amount of metal (T), and more preferably 20% or less.

The rare earth element R is Pr, N which is an R ₁ element.
One or more elements selected from the group of elements d, Tb, and Dy are essential elements. La, Ce, or Y elements (hereinafter “R ₂ element”) that are rare earth elements other than the R ₁ element, Sm, and other elements (hereinafter “R ₃ element”) are not always required, and R ₁ element It is an element that can be mixed together. Making the R ₁ element an essential element is
As a hard magnetic phase, Nd ₂ Fe ₁₄ B having a particularly high magnetic anisotropy
This is to secure a compound having a type crystal structure. That is,
This is because a high uniaxial magnetic anisotropy can be obtained when the Nd position of the Nd ₂ Fe ₁₄ B type crystal phase is replaced with the R ₁ element, and therefore the R ₁ element is 30% or more of the entire R element. Is preferred. It is more preferably at least 50% and even more preferably at least 60%. Further, among the R ₁ elements, Pr is an element that is particularly effective in increasing the coercive force,
From the viewpoint of maximizing the high coercive force, Pr is preferably 30% or more of the entire R element, and more preferably 50% or more. R ₂ element and R ₃ element, if the mixed amount is too much, since the magnetic anisotropy of the Nd ₂ Fe ₁₄ B type compound causes a decrease, R ₂ element,
It is preferably 50% or less of the total R element, more preferably 3
The content of R ₃ elements such as Sm is preferably 30% or less, more preferably 20% or less.

The element X (B, C) has B as an essential element, but most of it may be replaced with C. However, if the total amount of B is replaced with C and the composition is such that B is not contained at all,
R ₂ T ₁₇ compound is produced, and Nd ₂ required as a hard magnetic phase is formed.
Formation of the Fe ₁₄ B type compound (in this case, the R ₂ T ₁₄ C compound) becomes extremely difficult. Therefore, the amount of B is preferably at least 5% of the total amount of X element. Preferably 10
% Or more, more preferably 20% or more.

If desired, the magnetic film of the magnetic recording medium of the present invention is provided with a composition containing N in addition to the above elements. N does not directly contribute to the improvement of the magnetic properties of the magnetic film, but N has an effect of promoting crystallization for making the magnetic film formed by vapor deposition on the substrate by sputtering to have the above-described two-phase mixed phase crystal structure. . That is, the deposited film formed on the substrate by sputtering the target is an amorphous body that does not form a two-phase mixed phase crystal structure as it is and has a uniform chemical composition over the entire film body. It is necessary to perform a heat treatment for structurally converting (crystallizing) this into a film body having a predetermined mixed phase structure composed of a soft magnetic phase and a hard magnetic phase. By containing an appropriate amount of N, crystallization thereof is facilitated, and it becomes possible to successfully achieve a predetermined crystallization at a relatively low heat treatment temperature. Therefore, the N content (atomic ratio) is preferably about 0.
It is at least 05%, more preferably at least 0.1. However, if the amount is too large, the hard magnetic phase Nd ₂
Since the production of the Fe ₁₄ B type compound is hindered and the effect of exhibiting the high coercive force of the magnetic film is reduced, it is preferably 3% or less. It is more preferably 1% or less.

Further, the magnetic film of the magnetic recording medium of the present invention comprises:
For the purpose of improving its magnetic properties / electrical properties, corrosion resistance, weather resistance, wear resistance, etc., Al, Si, Cu,
One or more elements selected from the group of elements such as Ga, Ag, Au, P (the total amount (atomic ratio) may be about 3% or less), Tc, V, Cr, Mn, Zr. , Hf,
It is also possible to have a component structure containing one or more elements selected from the group of elements such as Mo and W (the total amount (atomic ratio) may be about 2% or less), and the component design is ,
Various modes are possible for the purpose of improving desired characteristics within a range that does not impair the gist of the present invention.

Next, the target and sputtering film formation for forming the magnetic film having the fine mixed phase structure will be described. A target having a chemical composition represented by the above formula [I] (Al, Si, Cu, G, if desired)
a, Ag, Au, P, Tc, V, Cr, Mn, Zr, H
f, Mo, W, etc.) is provided as a component composition containing one or more elements such as f), Mo, W) as a casting material (ingot) of the alloy melt adjusted to a predetermined component composition, or atomizing the alloy melt. Using powder that has been pulverized by the method etc. as a raw material,
It can be manufactured as a sintered alloy by a hot isostatic pressing method or the like. If desired, the target material may be subjected to hot working (hot rolling, hot forging, etc.) to be subjected to spattering as a plastically processed product with enhanced homogeneity of composition and density. Is not particularly different.
The target used in the present invention is not necessarily limited to one manufactured as an alloy containing all of the constituent elements as desired, and the constituent elements are divided into several blocks and those Also included are those produced by combining them so as to have the chemical composition of. For example, even if a block of a rare earth element prepared separately is fitted into the plate surface of a plate-shaped block of an alloy composed of an iron group transition metal element T and an X element, and combined so as to have a predetermined chemical composition as a whole. Good. Providing a target manufactured as a combination of multiple blocks in this way for spattering is
For example, it is effective as a method for efficiently performing the sputtering film formation while maintaining the constituent elements of the target having different sputtering evaporation rates depending on the kind of the elements at a predetermined composition ratio.

The formation of the magnetic film by the sputtering of the target can be carried out in a reduced pressure atmosphere of argon gas in the same manner as usual, but a means for promoting the crystallization of the sputtering film formed on the substrate. As
When it is desired to contain an appropriate amount of N (about 0.05 to 3%) in the deposited film, it is advisable to add a small amount of nitrogen gas to the sputtering atmosphere to perform sputtering. The nitrogen gas concentration of the spatula atmosphere is about 100 ppm to 5
% Is appropriate, and the N content of the vapor deposition film formed on the substrate can be easily and accurately controlled by adjusting the nitrogen gas concentration in the sputter atmosphere.

Crystallization of a vapor deposition film formed on a substrate by sputtering is performed by (i) heating and holding the substrate to form a vapor deposition film, (ii) heating and holding the substrate, or sputtering without heating. This can be achieved by applying a method such as heating the vapor-deposited film after forming the vapor-deposited film. In spattering in which a substrate is heated and held to form a vapor deposition film, the diffusion effect of atoms in the vapor deposition film is promoted as a heating effect of the substrate, and as the sputtering of the sputtering progresses, crystallization of the vapor deposition film occurs and softening occurs. A magnetic film having a fine mixed phase crystal structure composed of a magnetic phase and a fine hard magnetic phase is formed. The heating temperature of the substrate is about 20.
It is required to be 0 ° C or higher, preferably 300 ° C or higher, and more preferably 350 ° C or higher. The higher the heating temperature,
While crystallization is promoted, if the heating temperature is too high, the Exchage-spring Magnet effect is reduced and it becomes difficult to secure a high coercive force due to the increase in the particle gap due to the coarsening of the crystal grains of the hard magnetic phase. The noise characteristic improving effect is reduced and the squareness of the magnetization curve is deteriorated. Therefore, about 60
It is preferable that the upper limit is 0 ° C. More preferably about 55
It is 0 ° C or lower.

On the other hand, when a vapor deposition film (amorphous film body) is formed by performing sputtering on the substrate without heating and holding it, and heat treatment is applied to the film, a soft magnetic property is formed in the amorphous film body during the heat treatment. A phase (Co ₃ B phase) is generated, and then fine crystals of a hard magnetic phase having an Nd ₂ Fe ₁₄ B type crystal structure are precipitated in the soft magnetic phase to form a fine mixed phase structure of two phases. The heating temperature for this crystal formation is about 350 ° C. or higher, preferably 450 ° C. or higher, more preferably 50 ° C. or higher.
It is 0 ° C or higher. However, adopting an excessively high temperature makes it difficult to secure high coercive force, noise characteristics, and good squareness of the magnetization curve as the hard magnetic phase particles aggregate and grow, as described above. This causes a problem such as thermal deformation. Therefore, about 800 ℃
Is preferably the upper limit, and is preferably about 700 ° C. or lower.

The heating and holding of the substrate in the above-mentioned sputtering process for crystallizing the sputtered vapor deposition film and the heat treatment of the vapor deposition film after the sputtering are combined as required. Implementation of this two-step heat treatment facilitates the achievement of appropriate control of crystallization of the magnetic film. Although the optimum temperature of the heat treatment for imparting the fine mixed phase crystal structure to the magnetic film is not uniform due to its component constitution (and N content) and the like,
By proper crystallization, the noise characteristics and coercive force improving effect of the magnetic film are maximized. Its coercive force far exceeds that of the conventional one, reaching about 3 to 4 KOe or more. In addition, the crystallinity of the fine mixed-phase crystal structure of the magnetic film (volume ratio of hard magnetic phase, its particle size, distance between particles, etc.)
Can be controlled by the heat treatment temperature, and the magnetic film exhibits a coercive force corresponding to its crystallinity. Therefore, the magnetic recording medium has an arbitrary coercive force depending on the usage conditions in an actual machine (for example, the strength of the magnetic field of the corresponding magnetic head) by the heat treatment conditions for crystallizing the magnetic film body. Can be made.

The sputtering method for producing the magnetic recording medium of the present invention has no special condition or limitation except that the treatment for crystallizing the sputtering film is added as described above, and the sputtering method is in accordance with a conventional method. Can be done. The film thickness of the magnetic film is, for example, 200 to 1000 Å
It may be the same as that of a Cr alloy magnetic film or the like.
The non-magnetic substrate on which the sputtering film is formed is, for example, a glass plate (amorphous glass, crystallized glass, etc.), an aluminum alloy plate,
Known materials such as carbon plate and titanium plate may be appropriately selected and used. However, in the present invention, since heat treatment for crystal formation of the magnetic film is required as described above, from the viewpoint of heat resistance of the substrate. Glass plates (particularly crystallized glass), carbon plates, titanium plates, etc. are advantageously used as compared with aluminum alloy plates. When performing sputtering film formation of the magnetic film on the substrate, if necessary, various film treatments, for example, formation of a film surface for imparting non-magnetism, or in-plane magnetization of the magnetic film or a magnetic recording method of perpendicular magnetization. In order to protect the surface of the magnetic film, for example, a lubricating protective film against contact with the magnetic head (such as a carbonaceous film such as graphite, silicon oxide or silicon nitride, etc. (Ceramics film, liquid lubrication film, etc.) may be appropriately laminated.
It is not particularly different from that of the conventional general magnetic recording medium.

[0022]

According to the present invention, magnetic recording having a high noise characteristic and a high coercive force far surpassing those of a conventional magnetic recording medium using a Co-based alloy or other ferromagnetic alloy film material as a magnetic recording film. The medium can be obtained. The coercive force exceeds, for example, 2 KOe and reaches 3 to 4 KOe or more. Moreover, the high coercive force can be obtained without using an expensive element such as Pt, which is advantageous in terms of cost. Further, the coercive force of the magnetic recording medium of the present invention can be controlled to be high or low by the crystallization heat treatment conditions of the magnetic film,
The coercive force that suits the actual conditions of use can be provided at will, and its industrial value is extremely large.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Funakoshi 64 Nishimukojima-cho, Amagasaki City, Hyogo Prefecture Kubota Amagasaki Plant Co., Ltd. (72) Takashi Nishi Nishi 64, Nishimukaijima-cho Amagasaki City, Hyogo Prefecture (72) Inventor Isao Endo 1-47 Shikazu Higashi 1-47, Naniwa-ku, Osaka City Kubota Inc. (72) Inventor Yoshinobu Okumura 1-2-47 Shikitsu Higashi, Naniwa-ku, Osaka City Kubota Inc. ( 72) Inventor Yang Xingha 1-47 Shikitsuhigashi, Naniwa-ku, Osaka City Kubota Corporation

Claims (4)

[Claims] 1. A magnetic recording film comprising a fine mixed phase in which fine particles of a hard magnetic compound having a Nd ₂ Fe ₁₄ B type crystal structure are densely dispersed in a matrix made of a soft magnetic compound containing Co as a main component. A magnetic recording medium having a magnetic film body of tissue. 2. The formula: T _100-uv R _u X _v , wherein T is an iron group transition metal element, R is a rare earth element, and X is B.
Or C, which represents the atomic composition ratio, u is 0.5 to 9%, and v is 5 to 25%.
%, The iron group transition metal element T has Co as an essential element, Ni and / or Fe can be mixed, and when Ni and / or Fe are mixed, the ratio of Co to the entire T is 50.
%, And the rare earth element R is one or more selected from Pr, Nd, Tb, or Dy (hereinafter, “R ₁ element”) as an essential element, and La, Ce, Y, Sm And one or more elements of other rare earth elements are allowed to be mixed, and when these elements are mixed, the ratio of the R ₁ element to the entire R is 30% or more, and the element X has B as an essential element, When C is mixed in this, the ratio of B to the entire X is 5% or more. ] The sputtering target for magnetic recording film formation characterized by having a chemical composition shown by these. 3. A method for forming a magnetic recording film on a non-magnetic substrate by sputtering a target as claimed in claim 2.
(I) the substrate is heated and maintained at a temperature of 200 ° C. or higher to form a sputtering film on the substrate, or (ii) the substrate is heated and maintained at a temperature of 200 ° C. or higher, or The magnetic recording film for a magnetic recording medium according to claim 1, wherein the sputtering film is formed on the substrate without heating and holding, and then the film is heat-treated at a temperature of 350 ° C. or higher. Method. 4. Nitrogen gas 100 ppm to 5% (volume ratio)
4. The method of forming a magnetic recording film of a magnetic recording medium according to claim 3, wherein the sputtering is performed in an atmosphere containing