JP2771664B2 - Soft magnetic alloy film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a soft magnetic alloy film suitable for a magnetic head or the like.

[Prior Art] In the field of magnetic recording, a high coercive force of a recording medium such as a magnetic tape is being promoted in order to increase a recording density. However, a saturation magnetic flux density (Bs) is used as a material of a magnetic head corresponding thereto. Are required. In addition, in order to obtain a magnetic head with high reliability such as wear resistance and environmental resistance, it is necessary to perform gap formation and the like by glass welding, which includes thermal stability that can withstand the high temperature of the glass welding process. Requests are being made.

As a conventional soft magnetic material (film) with a high saturation magnetic flux density, Ni
-Fe (Permalloy) and Fe-Si-Al alloy (Sendust) are typical, but in recent years, amorphous alloy films mainly composed of Co which is a ferromagnetic metal element have been developed.

Also, as a recent attempt, the influence of the magnetocrystalline anisotropy of Fe (the adverse effect on soft magnetism) has been reduced by using an alloy film (Fe-N, Fe-C, etc.) composed of fine crystals containing Fe as the main component. In some cases, a film having a high saturation magnetic flux density and excellent soft magnetic properties is obtained.

[Problems to be Solved by the Invention] The conventional NI-Fe film has the drawbacks that the soft magnetic properties are degraded by the high temperature of the glass welding step and the magnetic resistance is low.

In addition, the saturation magnetic flux density of a Co-based amorphous film
If suppressed below, welding with low melting point glass with melting point of about 500 ° C is possible, but welding with medium to high melting point glass with melting point of 600 ° C or more is difficult, and medium to high melting point with excellent environmental resistance There is a problem that glass cannot be used.

In addition, the alloy film of the fine crystal causes crystal growth due to bone sound and deteriorates soft magnetism (in the case of Fe-C, 400 ° C. is the maximum glass welding temperature), so that it is also suitable for glass welding. Hard to say.

Against this background, the present inventors have filed Japanese Patent Application No. 1-5557.
No. 1, Japanese Patent Application No. 1-278220, etc., filed a patent application for a soft magnetic alloy film which solved the above-mentioned problems.

One of the soft magnetic alloy films for which a patent application is filed in Japanese Patent Application No. 1-55571 is a composition formula represented by Co _x M _z C _w
Is one or more of Ti, Zr, Hf, Nb, Ta, Mo, and W, and the composition ratio x is 55 to 96 in atomic%, z is 2 to 25, z is 0.1 to 20, x
+ Y + z = 100 was satisfied.

In the other one, the composition ratio is represented by Co _x T _y M _z C _w , and T is F
e, Ni, or Mn, at least one of which has a composition ratio x of 50 at.
~ 96, y is 0.1-20, z is 2-25, w is 0.1-20, x + y
+ Z + w = 100 was satisfied.

Furthermore, one of the soft magnetic alloy film which is patent in Pat Hei 1-278220, the composition formula is represented by Fe _x M _z C _w, the composition ratio x is atomic% 50 to 96, z Is 2 to 30, w is 0.5 to 2
5. The relationship x + z + w = 100 was satisfied.

Further, the other one composition formula is represented by _{Fe x T y M z C w} , the composition ratio x is atomic% 50 to 96, y is 0.1 to 10, z is 2 to 30, w is
0.5 to 25, x + z + w = 100 was satisfied.

The soft magnetic alloy films provided in these patent applications have a high saturation magnetic flux density of 15000 G or more for some compositions, and have high thermal stability compared to conventional various materials.
There were also problems described below.

The upper limit of the heat treatment temperature of the soft magnetic alloy film is about 700 ° C. At a temperature higher than 700 ° C., the hard magnetic property starts to deteriorate.

The saturation magnetic flux density of the soft magnetic alloy film is excellent as described above, and reaches about 18000 G in the case of a specific composition, but cannot cope with a case where a higher saturation magnetic flux density is required.

Among the soft magnetic alloy films, a Fe-based alloy film does not cause a practical problem in terms of corrosion resistance, but still has a problem inferior to permalloy in corrosion resistance.

The present invention solves the above-mentioned problems, and withstands a heat treatment at a higher temperature than the soft magnetic alloy film provided by the present inventors, and has a higher saturation magnetic flux density, and a soft magnetic alloy film having excellent corrosion resistance. It is intended to provide.

For the invention described in claim 1 [Means for Solving the Problems] To solve the above problems, the composition formula is represented by _{(Fe x Co y) a M} b C c, M is Ti, Z
r, Hf, V, Nb, Ta, Mo, W is a metal element or a mixture of at least one of them, and the composition ratio x, y is 0.25 ≦ x
≦ 0.87, 0.13 ≦ y ≦ 0.75, x + y = 1, composition ratio a, b, c is 50% ≦ a ≦ 96% in atomic%, 2% ≦ b ≦ 30%, 0.5 ≦ c ≦ 25
%, A + b + c = 100%,
The metal structure is composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is included in a part of the crystal grains.

In order to solve the above problem, the invention described in claim 2 has a composition formula represented by (Fe _x Ni _z ) a M b C c, where M is Ti, Z
r, Hf, V, Nb, Ta, Mo, W is a metal element or a mixture of one or more kinds, and the composition ratio x, z is 0.05 ≦
x ≦ 0.87, 0.13 ≦ z ≦ 0.95, x + z = 1, composition ratios a, b, c are 50% ≦ a ≦ 96%, 2% ≦ b ≦ 30%, and 0.5 ≦ c ≦ 25 in atomic%.
%, A + b + c = 100%,
The metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of the carbide of the element M is contained in a part of the crystal grains.

According to a third aspect of the present invention, in order to solve the above-mentioned problem, a composition formula is represented by (Co _y Ni _Z ) a M b C c, and M is Ti,
Zr, Hf, V, Nb, Ta, Mo, a metal element or a mixture of one or more of W, the composition ratio y, z is 0.5 ≦ y ≦
0.75, 0.25 ≦ z ≦ 0.50, y + z = 1, composition ratio a, b, c is 50% ≦ a ≦ 96% in atomic%, 2% ≦ b ≦ 30%, 0.5 ≦ c ≦ 25
%, A + b + c = 100%,
The metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of the carbide of the element M is contained in a part of the crystal grains.

In order to solve the above problem, the invention described in claim 4 has a composition ratio represented by (Fe _x CO _y Ni _z ) a M b C c, where M is T
Among i, Zr, Hf, V, Nb, Ta, Mo, and W, it is a metal element or a mixture of at least one kind, and the composition ratio x, y, z is the atomic ratio 0 <
y ≦ 0.87, 0 <z ≦ 0.75, 0 <z ≦ 0.95, x + y + z =
1, where z> 0.05 ≦ x ≦ 0.50, composition ratios a, b, c are 50% ≦ a ≦ 96% in atomic%, 2% ≦ b ≦ 30%, 0.5 ≦ c ≦ 2
While satisfying the relationship of 5%, a + b + c = 100%,
The metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is contained in a part of the crystal grains.

In order to solve the above-mentioned problem, the invention described in claim 5 has a composition formula represented by (Fe _x CO _y Ni _z ) a M b C c, where M is T
Among i, Zr, Hf, V, Nb, Ta, Mo, and W, a metal element or a mixture composed of at least one kind, and the composition ratio x, y, z is 0.1 at atom ratio.
0 ≦ x ≦ 0.87, 0 <y ≦ 0.75, 0.1 <z ≦ 0.9, x + y +
z = 1, provided that when z <0.5, 0.95 ≦ y ≦ 0.75, and the composition ratios a, b, c are 60% ≦ a ≦ 90%, 4% ≦ b ≦ 20%, 6% ≦ c ≦ in atomic%. 20
%, A + b + c = 100%, and
A soft magnetic alloy film whose metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is contained in a part of the crystal grains.

For the invention described in claim 6 to solve the above problems, the composition formula is represented by _{(Fe x Ni z) a M} b C c, M is Ti, Z
r, Hf, V, Nb, Ta, Mo, W, among at least one metal element or a mixture, the composition ratio x, z is 0.10 ≤ element ratio
x ≦ 0.50 ≦ z ≦ 0.90, x + z = 1, composition ratio a, b, c is 60% ≦ a ≦ 90% in atomic%, 4% ≦ b ≦ 20%, 6% ≦ c ≦ 20%,
a + b + c = 100%, and the metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a part of the crystal grains includes a crystal phase of a carbide of element M. Soft magnetic alloy film.

The invention described in claim 7 is the invention described in claim 1,2,3,4,5 or 6 in which the metal structure is composed of fine crystal grains and an amorphous phase in order to glitch the problem. It is.

 Hereinafter, the present invention will be described in more detail.

As a method of forming the alloy film, the alloy film is formed by a thin film forming apparatus such as sputtering or vapor deposition. As the sputtering apparatus, an existing apparatus such as RF two-pole sputtering, DC sputtering, magnetron sputtering, three-pole sputtering, ion beam sputtering, facing target type sputtering, or the like can be used. As a method of adding C into the film, a method of arranging graphite pellets on a target plate to form a composite target and sputtering it, or a method of adding C
The use of a target (Fe-Co-Ni-M system, etc.) that does not contain, the Ar reactive sputtering sputtering in a gas atmosphere of a mixture of hydrocarbon gas methane (CH ₄₎ or the like in an inert gas such as such Since the C concentration in the film can be easily controlled by the reactive sputtering method, a film excellent in a desired C concentration can be obtained.

Since the film thus produced contains an amorphous phase in a considerable proportion and is unstable,
Microcrystals are deposited by performing a heat treatment of heating to 400 ° C. or higher. By performing this heat treatment in a static magnetic field or a rotating magnetic field, more excellent soft magnetic characteristics can be obtained. Further, this heat treatment can be performed also as a glass welding step in the manufacturing process of the magnetic head.

The step of depositing the microcrystals does not need to be performed completely, and it is sufficient that a considerable number (preferably 50% or more) of the microcrystals are precipitated, so that the amorphous component may remain partially. The remaining amorphous component does not hinder the improvement of the characteristics.

Hereinafter, the reasons for limiting the components as described above will be described.

Fe, Co, Ni are the main components and are the elements responsible for magnetism,
In order to obtain a saturation magnetic flux density of at least ferrite (Bs 5000G) or more, a ≧ 50% is required. Further, in order to obtain good soft magnetic properties, a ≦ 96% must be satisfied.

The elements M and C are necessary for refining the crystal to improve soft magnetic properties, and for maintaining soft magnetic properties and thermal stability, b ≧ 2% and C ≧ 0.5%. . On the other hand, if it is too large, the saturation magnetic flux density is lowered, and the distribution density of carbides of the element M is increased, so that each of the crystals bearing the ferromagnetism becomes single magnetic domain particles and the soft magnetic properties are lost. %, C ≦ 25%.

The fine crystals of the carbide of the element M function as pinning sites for the domain wall, have the function of improving the high-frequency characteristics of magnetic permeability, and are uniformly dispersed in the film to form Fe, Co, Ni.
It has the function of preventing the growth of microcrystals rich in iron by heat treatment and impairing the soft magnetism. In other words, the crystal grains rich in Fe, Co, and Ni grow and grow, and the adverse effect of the magnetocrystalline anisotropy increases, and the soft magnetic characteristics deteriorate. However, the fine crystals of the carbide of the element M are reduced to Fe, Co, Ni. By acting as a barrier for grain growth of crystal grains rich in soft magnetic properties, deterioration of soft magnetic properties is prevented.

Regarding the Ni content, a high saturation magnetic flux density can be obtained in the composition range of 0 ≦ z ≦ about 0.1. In this case, x> 0.87 or y
> 0.7, the inventors of the present application have previously filed a patent application for F
Only the same saturation magnetic flux density as the e-MC film can be obtained.

In the composition range of z ≧ 0.1, a film having high thermal stability and excellent corrosion resistance can be obtained. In this case, 0 ≦ x <0.05 and z> 0.
Since good soft magnetic characteristics cannot be obtained in the composition region of 5, this composition region must be removed. Further, if x> 0.87, the present inventors show only the same level of corrosion resistance as the Fe-MC film applied for a patent earlier, so it is necessary to satisfy x ≦ 0.87. Furthermore, when y> 0.75, the present inventors show only the same level of corrosion resistance as the Co-MC film applied for a patent earlier, so that y ≦ 0.75 is required.

In the alloy film of the present invention, by combining Fe, Co, and Ni, the magnetocrystalline anisotropy energy of each crystal is reduced, and the soft magnetic characteristics can be maintained even when the crystal is increased to some extent by high-temperature heat treatment. Has features.

Further, by containing Ni having good corrosion resistance, the present inventors have excellent corrosion resistance as compared with the Fe-MC film which the present inventors applied for a patent for earlier.

And, since the metal structure is basically composed of microcrystals of 0.08 μm or less, more preferably 0.05 μm or less, it is superior in thermal stability compared to amorphous, and can reduce the amount of added elements, and can reduce the saturation magnetic flux. Density can be increased.

Further, in the soft magnetic alloy film of the present invention, the composition formula (Fe
_x Co _y Ni _z ) _a Mb Cc, and in the soft magnetic alloy film having a composition ratio in the range described in claims 5 and 6, an initial magnetic permeability of 500 or more can be obtained. By setting the composition, a film having more excellent soft magnetic properties can be obtained.

[Example] Using an RF bipolar sputtering apparatus, a composite target having a Ta or Hf pellet disposed on a Fe-Ni alloy, Fe-Co alloy, Co-Ni alloy or Fe-Co-Ni alloy target, A soft magnetic alloy film having a thickness of 5 to 6 μm was produced by sputtering in a mixed gas of Ar + CH ₄ .

The Ta content was set to approximately 7.5 at% and the Co content was set to approximately 12 at%, and the Fe: Co: Ni ratio (x: y:
z) was changed to various values.
FIG. 1 shows the result of measuring the value of the initial magnetic permeability at 1 MHz after annealing in a rotating magnetic field for 1 minute.

From the results shown in FIG. 1, according to the composition range of the present invention,
It was found that an initial magnetic permeability (μ) of 200 or more could be obtained.
Further, it was also found that the region where the initial magnetic permeability of 500 or more was obtained was a portion indicated by double oblique lines in FIG. Table 1 shows typical characteristics of these films.

Table 2 shows Ni _64.4 as an example showing high thermal stability.
The magnetic properties of the soft magnetic alloy film having the composition of Fe _16.9 Ta _6.7 C _12.0 after the magnetic field-free heat treatment at each temperature are shown.

As apparent from the comparison with the film having a composition of Fe _74.1 Ta _11.5 C _14.4 (a film having a composition to which the present inventors previously applied for a patent) listed in Table 2 as a comparative example, the film having the composition of the present invention is evident. Had a higher thermal stability and showed an initial permeability of 550 at 5 MHz even after heat treatment at 730 ° C.

Next, Table 3 shows an example of magnetic properties of a film mainly composed of Fe-Co-MC as a soft magnetic alloy film having the above composition and exhibiting a high saturation magnetic flux density.

As is apparent from Table 3, the initial magnetic permeability of the film of the present invention is lower than that of the Fe-MC-film or the Co-MC film filed by the inventors of the present invention, but is up to 20,000 G. It shows a high saturation magnetic flux density, which proves to be excellent for magnetic heads.

Next, as an evaluation of the corrosion resistance (environmental resistance) of the film, the degree of discoloration after being left for 500 hours in an environment of 60 ° C. and a relative humidity of 95% was visually determined. Table 4 shows the results.

As is clear from Table 4, the Ni-containing film of the present invention was found to be superior in environmental resistance as compared with the Fe-MC film or the Co-MC film.

[Effects of the Invention] As described in detail above, the present invention is a soft magnetic alloy film composed of fine crystal grains containing Fe, Co, and Ni as main components, in which addition of a component that lowers the saturation magnetic flux density is restricted. Higher saturation flux density than Sendust alloy film
High saturation magnetic flux density exceeding 000G can be obtained.

In addition, elements M (Ti, Zr, Hf, Nb, Ta, Mo, W) and C, which improve soft magnetism, are added, and the metal structure is composed of fine crystal grains. Since the adverse effect on the soft magnetism due to the properties is reduced, good soft magnetic properties can be obtained. Furthermore, since the added element M forms carbides with C while being composed of fine crystal grains, even when heated to 700 ° C. or more in the glass welding step, the crystal grains do not become coarse, and the above characteristics are satisfied. maintain. Therefore, when manufacturing a magnetic head, it can be welded with a medium to high melting point glass,
A magnetic head having excellent environmental resistance can be obtained, and a magnetic head having high performance required for high-density recording can be provided.

Further, the alloy film to which Ni is added has excellent corrosion resistance and excellent environmental resistance as compared with the Fe-MC film which the present inventors applied for a patent before.

[Brief description of the drawings]

FIG. 1 is a triangular composition diagram for explaining the composition of the alloy film of the present invention.

Continuation of the front page (56) References JP-A-2-229406 (JP, A) JP-A-3-16203 (JP, A) JP-A-3-20444 (JP, A) JP-A-3-131006 (JP) , A) JP-A-3-158441 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 10/12

Claims (7)

(57) [Claims] The composition formula is represented by (Fe _x CO _y ) _a M _b C _c , where M is T
Among i, Zr, Hf, V, Nb, Ta, Mo, W, a metal element or a mixture of one or more kinds, and the composition ratio x, y is 0.25 ≦ x ≦ 0.87 0.13 ≦ y ≦ 0.75 in atomic ratio. x + y = 1 The composition ratios a, b, and c are expressed in terms of atomic% (at%): 50% ≦ a ≦ 96% 2% ≦ b ≦ 30% 0.5% ≦ c ≦ 25% a + b + c = 100% A soft magnetic alloy film whose metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is contained in a part of the crystal grains. 2. The composition formula is represented by (Fe _x Ni _z ) _a M _b C _c , where M is T
Among i, Zr, Hf, V, Nb, Ta, Mo, W, a metal element or a mixture of one or more kinds, and the composition ratio x, z is 0.05 ≦ x ≦ 0.87 0.13 ≦ z ≦ 0.95 in atomic ratio. x + z = 1 The composition ratios a, b, and c satisfy the following relationship in atomic% (at%): 50% ≦ a ≦ 96% 2% ≦ b ≦ 30% 0.5% ≦ c ≦ 25% a + b + c = 100% A soft magnetic alloy film whose metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is contained in a part of the crystal grains. 3. The composition formula is represented by (Co _y Ni _z ) _a M _b C _c , where M is T
Among i, Zr, Hf, V, Nb, Ta, Mo, W, a metal element or a mixture of one or more kinds, and the composition ratio x, z is 0.50 ≦ y ≦ 0.75 0.25 ≦ z ≦ 0.50 in atomic ratio. y + z = 1 The composition ratios a, b, and c are expressed in terms of atomic% (at%): 50% ≦ a ≦ 96% 2% ≦ b ≦ 30% 0.5% ≦ c ≦ 25% a + b + c = 100% A soft magnetic alloy film whose metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is contained in a part of the crystal grains. 4. The composition formula is represented by (Fe _x Co _y Ni _z ) _a M _b C _c ,
Is a metal element or a mixture of at least one of Ti, Zr, Hf, V, Nb, Ta, Mo, and W, and the composition ratio x, y, z is 0 <x ≦ 0.87 0 < y ≦ 0.75 0 <z ≦ 0.95 x + y + z = 1 However, when z> 0.5, 0.05 ≦ x ≦ 0.50 The composition ratios a, b, c are 50% ≦ a ≦ 96% in atomic% (at%) 2% ≦ b ≦ 30% 0.5% ≦ c ≦ 25% a + b + c = 100% In addition to satisfying the following relationship, the metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less. A soft magnetic alloy film containing a carbide crystal phase. 5. The composition formula is represented by (Fe _x Co _y Ni _z ) _a M _b C _c ,
Is a metal element or a mixture of one or more of Ti, Zr, Hf, V, Nb, Ta, Mo, and W, and the composition ratio x, y, z is 0.10 <x ≦ 0.870 < y ≦ 0.75 0.1 <z ≦ 0.9 x + y + z = 1 However, in the case of z <0.5 0.05 ≦ y ≦ 0.75 The composition ratio a, b, c is 60% ≦ a ≦ 90% 4% ≦ b ≦ in atomic% (at%) 20% 6% ≦ c ≦ 20% a + b + c = 100%, and the metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less. A soft magnetic alloy film containing a carbide crystal phase. 6. The composition formula is represented by (Fe _x Ni _z ) _a M _b C _c , where M is T
Among i, Zr, Hf, V, Nb, Ta, Mo, W, a metal element or a mixture of one or more kinds, and the composition ratio x, y, z is 0.10 ≦ x ≦ 0.50 0.50 ≦ z in atomic ratio. ≦ 0.90 x + z = 1 The composition ratios a, b, and c satisfy the following relationship in atomic% (at%): 60% ≦ a ≦ 90% 4% ≦ b ≦ 20% 6% ≦ c ≦ 20% a + b + c = 100% In addition, a soft magnetic alloy film whose metal structure is mainly composed of fine crystal grains having an average crystal grain size of 0.08 μm or less, and a crystal phase of a carbide of the element M is partially contained in the crystal grains. 7. The soft magnetic alloy film according to claim 1, wherein the metal structure is composed of fine crystal grains and an amorphous phase.