JP3201892B2 - Soft magnetic thin film and magnetic inductive MR head using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic thin film, and more particularly to a soft magnetic thin film having a low coercive force and a high saturation magnetic flux density manufactured by an electroplating method.

[0002]

2. Description of the Related Art Magnetic thin films of thin film magnetic heads and thin film transformers are required to have excellent soft magnetic properties such as low coercive force and high saturation magnetic flux density.

[0003] These magnetic thin films are generally formed by a vapor phase film forming method such as a sputtering method or a liquid phase film forming method such as a plating method. There is an advantage that a film having a large area can be easily formed and a film with high uniformity can be obtained, and the number of steps is small and the equipment is inexpensive.

[0004] From this fact, electrodeposition permalloy (Ni
-Fe alloy) film is currently widely used as a thin film head magnetic pole material.

The recent increase in recording density is largely due to the increase in coercive force (Hc) of the recording medium. In order to write sufficiently on a recording medium having a large coercive force, it is necessary to generate a stronger magnetic field from the recording head. Also, M
As for the magnetic material of the shield layer of the R (magnetic resistance) inductive composite head, a high saturation magnetic flux density material that can be expected to have a desired shielding effect with a thinner film is required for high-density recording. However, the permalloy has a saturation magnetic flux density (Bs) of 1T or less, and a material having a higher saturation magnetic flux density (Bs) is required.

As one of the magnetic plating films satisfying the requirements for the magnetic properties, there is a Co-Ni-Fe alloy.

Regarding the magnetic properties of the bulk material of this Co—Ni—Fe alloy, see RMBozorth, Ferromagnetism, 19
51 (D. Van Nostrand Company, Inc.). According to FIG. 5-84 described therein, the coercive force (Hc) decreases only in the composition with a small amount of Co, and particularly, Hc <0.3 Oe is limited to a small composition range. Understand.

[0008] JP-B-63-53277 discloses an electroplating bath composition of a cobalt-nickel-iron alloy, which is used for electroplating to obtain a low coercive force and a high saturation magnetization. (4πMs), and 0
Alternatively, a cobalt-nickel-iron alloy coating having a slightly negative magnetostriction is shown to be obtained. In this case, it is described that the coercive force (Hc) is 2 Oe or less. In the case of the CoNiFe coating (about 80:10:10) shown in the example, 4πMs = 16 kG and Hc = 1.5 Oe are obtained. Although 4πMs is almost twice the value of Permalloy, the coercive force is considerably higher than that of Permalloy, and the soft magnetic characteristics are inferior.

US Pat. No. 5,011,581 (corresponding to Japanese Patent Application Laid-Open No. 2-138716) discloses a method for producing a high saturation magnetic flux density alloy thin film by an electrodeposition method. As shown in the membrane samples of the examples, Bs is 10500 to 185.
Although it is high in the range of 00G, Hc is 10 Oe at the minimum, and the soft magnetic properties are not sufficient.

Japanese Patent Application Laid-Open No. 2-68906 discloses F
e, Co and Ni as main components, Fe is 20 to 75 at%,
Co is 5-45 at%, Ni is 20-70 at%, and the (220) plane or (1) of the face-centered cubic lattice structure is used as the thin film surface.
11) A high saturation magnetic flux density soft magnetic film in which the plane is preferentially plane-oriented is disclosed. As a method for producing the film, a vapor deposition method and an electrodeposition method are shown. In the examples, the sample prepared by the electrodeposition method is Fe ₂₉ Co ₇ Ni ₆₄ of (111) orientation (the numerical value is
at%), only Hc is 2.5 Oe, and the soft magnetic properties are not sufficient.

A Co-Fe-Ni film having excellent corrosion resistance and a high saturation magnetic flux density is reported in 7pF-15 of the 16th Annual Meeting of the Japan Society of Applied Magnetics. %, Fe = 20-30 wt%, N
A plated soft magnetic film having a composition of i = 20 to 30 wt% is shown. This has a high Bs of 19 kG or more, but has a magnetic permeability (μ) of about 600 to 700,
It is estimated that the coercive force is large and lower than that of Permalloy.

From the above, it is desired to obtain a Co-Fe-Ni-based soft magnetic thin film having a high Bs and a low Hc by electroplating.

[0013]

The object of the present invention is usually to provide a solution of not more than 0.5 Oe, especially not more than 0.3 Oe, and more preferably not more than 0.2 Oe.
An object of the present invention is to provide a soft magnetic thin film having a low coercive force of Oe or less and a high saturation magnetic flux density.

[0014]

The above object is achieved by the following constitutions (1) to (5). (1) aCo-bNi-cFe [where a, b and c are the ratios (wt%) of Co, Ni and Fe, respectively]
Which satisfies the following relationships: a = 28 to 75 wt%, b = 16 to 60 wt%, c = 9 to 42 wt%, and a + b + c = 100 wt%. Having a composition represented by the following formula, and mainly having a face-centered cubic phase, and at least two phases having different crystal structures whose body-centered cubic phase is confirmed by electron diffraction. Soft magnetic thin film. (2) The soft magnetic thin film according to (1), which is heat-treated after the film formation. (3) The soft magnetic thin film according to (2), wherein the temperature of the heat treatment is 240 to 370 ° C. (4) The soft magnetic thin film according to any one of (1) to (3), wherein the sulfur content in the film is 1000 ppm or less. (5) A magnetic inductive MR head having the soft magnetic thin film according to any one of (1) to (4).

[0015]

[Specific Configuration] Hereinafter, a specific configuration of the present invention will be described in detail.

The soft magnetic thin film of the present invention contains Co, Ni and Fe. This soft magnetic thin film contains mainly a face-centered cubic phase and a small amount of a body-centered cubic (bcc) phase.

[0017]

When the soft magnetic thin film of the present invention mainly contains the fcc phase and contains a small amount of the bcc phase, the bc
When the peak intensity of the c (110) plane is I (110), I (200) / I (111) ≧ 0.1, preferably I (200) / I (111) ≧ 0.15, And I (110) / I (111) ≦ 0.1. In this case, normally, I (200) / I (111) ≦ 1, preferably I (200) / I (111) ≦ 0.2. In this case, I (200) / I (111)> 0.
When it is 2, the coercive force tends to increase.

The existence of the bcc phase can be confirmed by electron beam diffraction. Even when the bcc phase is confirmed by electron beam diffraction, when a general-purpose X-ray diffractometer is used, I (110) is used. In some cases, / I (111) = 0 and its existence cannot be confirmed. This is because X-ray diffraction is generally less sensitive than electron beam diffraction. In the present invention, if a bcc phase can be confirmed by electron beam diffraction, I (11
0) / I (111) = 0. Since the preferred composition range in the present invention is a composition range immediately before the bcc phase starts eutectoid, a very small amount of the bcc phase, which cannot be detected by a general-purpose X-ray diffractometer, is locally segregated, and high characteristics are obtained. It is thought that it has been obtained. Specifically, fc
A low coercive force should be obtained because the bcc phase precipitates at the grain boundaries of the crystal grains composed of the c phase, which promotes particle separation or changes in the direction in which the sum of crystal magnetic anisotropy decreases. Conceivable. On the other hand, I (110) / I (1
If 11)> 0.1, it is considered that the coercive force increases because the bcc phase itself is growing crystals or the influence of the crystal magnetic anisotropy of the bcc phase increases.

In the present invention, a Co—Ni—Fe soft magnetic thin film having a low coercive force and a high saturation magnetic flux density can be obtained by setting the structure of the crystal phase and the orientation of the crystal plane as described above.
In particular, the coercive force (Hc) is 0.5 Oe or less, preferably 0.5 Oe.
3 Oe or less, more preferably 0.2 Oe or less, particularly preferably 0.1 Oe or less can be realized, and exhibit extremely good soft magnetic properties. The saturation magnetic flux density (Bs) is about 13 to 20 kG.

Therefore, the soft magnetic thin film of the present invention is extremely useful as a magnetic thin film for a thin film head or a thin film transformer. In particular, the effect of improving the overwrite characteristics of the inductive MR head and the effect of improving the recording density by reducing the shield layer can be expected.

On the other hand, when the main phase is another crystal phase, Hc becomes high. Also, I (110) / I
When the bcc phase is mixed to the extent that (111)> 0.1 or when the fcc phase is the main phase, I (200) / I (1
11) If <0.1, Hc increases and good soft magnetic characteristics cannot be obtained (see FIG. 1). FIG. 1 shows f
What is indicated as cc + bcc is I (110) / I
(111)> 0.1.

In the present invention, in order to obtain a particularly desired structure, it is preferable to use permalloy as a base film. For example, if copper is used as a base film, a desired crystal structure cannot be obtained even with a film having the same composition, so that the soft magnetic characteristics deteriorate.
The thickness of the permalloy underlayer is usually 400 to 1000A.
Degree.

The soft magnetic thin film of the present invention preferably has the following composition in order to obtain a low Hc.

ACo-bNi-cFe In the above, a + b + c = 100 wt% and a = 2
8 to 75 wt%, further 30 to 60 wt%, especially 35 to
45 wt% is preferred, b = 16 to 56 wt%, and 2
0 to 50% by weight, particularly preferably 25 to 35% by weight, c =
9 to 42 wt%, furthermore 10 to 40 wt%, especially 25 to
Preferably it is 35% by weight.

The above a = 28-75 wt%, b = 1
The composition range represented by 6 to 56 wt% and c = 9 to 42 wt% is a region surrounded by a line connecting points A, B, C, and D shown in FIG. Hc of 0.5 Oe or less, especially 0.4 Oe or less is obtained.

The above a = 30 to 60 wt%, b = 2
The composition range represented by 0 to 50 wt% and c = 10 to 40 wt% is a region surrounded by a line connecting points E, F, G, H, I, and J shown in FIG. 0.3 in area
Hc less than Oe is obtained. Further, a = 35 to 45 wt%
, B = 25 to 35 wt%, and c = 25 to 35 wt%, the composition ranges indicated by points K, L, M, N, O, P shown in FIG.
Are enclosed by lines connecting the lines as shown in the figure. In these regions, Hc of 0.2 Oe or less is obtained. Therefore, in the above composition formula, if a, b, and c become too large or too small, it becomes difficult to obtain a low Hc.

The soft magnetic thin film of the present invention is preferably produced by an electroplating method, and the above film characteristics can be realized by selecting a plating bath composition, plating conditions and the like. It is also excellent in mass productivity. Furthermore, the plating bath used in the present invention has good stability.

Incidentally, Japanese Patent Laid-Open Publication No.
The table shows an Fe ₃₀ Co ₄₀ Ni ₃₀ film having a thickness of 1.9 μm formed by the sputtering method. This film is fc
c (1), but I (200) / I (111) is about 0.1
22, which is outside the scope of the present invention. No. 1 of the publication
The table describes that the coercive force of the thin film having the same composition is 0.42 Oe, which is higher than that of the thin film having the same composition in the present invention.

As will be described later, in the present invention, the coercive force can be further reduced by subjecting the fcc single-phase film to a heat treatment to precipitate a small amount of the bcc phase. It is described that time annealing is performed. However, the publication does not disclose that a bcc phase is precipitated by annealing and coercive force is lowered. FIG. 4 (A) and FIG. 4 (B) show changes in the average crystal grain size and the coercive force before and after annealing. The magnetic force increases after annealing. In this publication, the coercive force is decreased by annealing because the thin film formed by the sputtering method has a relatively large crystal grain size.

Table 3 of the publication discloses Fe ₃₀ Co ₄₀ Ni.
There is described a multilayer film in which ₃₀ films and 200 Fe ₈₆ Si ₁₄ films are stacked in each case. In this multilayer film, I (200) / I
(111) is about 0.15, and after annealing is about 0.15.
However, there is no example in which I (200) / I (111) ≦ 0.2 is obtained in a single-layer film which is easy to manufacture.

Further, an example of Japanese Patent Application Laid-Open No. 2-68906 discloses an electrodeposition film in which the (111) plane of the fcc structure is preferentially plane-oriented. However, since it differs from that of the present invention in plane orientation, a low coercive force as in the present invention cannot be realized. The publication also discloses that the (111) plane and (20)
Although a sputter-deposited film in which the (0) plane is preferentially oriented is also disclosed, it is different from the present invention because the sputter-deposition method or the plane orientation ratio is out of the range of the present invention. It is described that characteristics cannot be obtained.

Also, US Pat. No. 5,011,581 (Japanese Patent Laid-Open No. 2-138716) does not suggest any crystal structure or plane orientation, and cannot realize a low coercive force as in the present invention.

[0034]

As described above, the soft magnetic thin film of the present invention is preferably prepared by electroplating using permalloy as a base film. The plating bath used at this time contains Co ions, Fe ions, and Ni ions. The concentrations of Co ions, Fe ions, and Ni ions in the plating bath may be appropriately selected depending on the intended film composition and the like. Usually, the concentrations of Co ions, Fe ions, and Ni ions are each 0.01%. It is preferred to be from mol / liter to the solubility limit. If the concentration of each metal ion is low, the rate of metal deposition tends to decrease, which is not practical. C
The source of each ion of o, Fe, and Ni is preferably selected from water-soluble salts such as sulfate, sulfamate, acetate, and nitrate, and sulfate is particularly preferably used because it is inexpensive. . In addition, Co ions and Fe ions can be naturally dissolved by immersing a metal in a plating bath,
It can also be supplied by dissolving the anode by electrolysis.

The pH of the plating bath is 2 to 10, especially 2.5 to
Preferably, the bath temperature is 10 to 80 ° C,
Particularly, the temperature is preferably set to 35 to 45 ° C. P of plating bath
By setting H and the temperature in the above ranges, a good plating film can be obtained. On the other hand, when the pH decreases, the metal deposition rate decreases, and when the pH increases, the working environment deteriorates due to the generation of ammonia gas and the like. Further, when the bath temperature is lowered, the deposition rate of the metal is lowered, and when the bath temperature is raised, the stability of the bath cannot be obtained.

The plating bath may contain an organic brightener. Saccharin is preferred as the organic brightener. It is sufficient if the addition amount is 0.5 g / L or more, but it is preferably 1 to 6 g / L in consideration of consumption during use. In addition, the plating bath may appropriately contain a surfactant such as sodium lauryl sulfate, a component added to a normal electroplating bath such as boric acid, and ammonium chloride. Further, an organic acid ion, a reducing agent, a chelating agent and the like may be appropriately added as a stabilizer. Under general conditions, trivalent Fe ions precipitate, which is not preferable. However, when a stabilizer such as citric acid or tartaric acid or a chelating agent (complex forming agent) is added, not only precipitation does not occur, but also Hc decreases. Therefore, it is preferable that trivalent Fe ions be present in the bath.

Incidentally, fine particles and hydroxide in the plating bath may be removed by continuous filtering.

The anode is preferably an insoluble TiPt or ferrite electrode from the viewpoint of removing fine particles. However, since an oxidation reaction occurs at the anode, it is desirable to separate the cathode from the cathode by, for example, an ion exchange membrane.

The current density during film formation is 0.5 to 4.0 A / dm.
^2, and more preferably 0.5 to ^{2 A} / dm ² . By setting the current density within the above range, a good plating film can be obtained. In contrast, when the current density decreases, the metal deposition rate decreases,
When the current density increases, the particle size of the metal particles in the film increases and Hc decreases. In addition to the direct current, an alternating current combined type that performs pulse electrolysis and cathode dissolution is also possible.

As a solvent for the plating bath, non-aqueous solvents such as methyl alcohol, dimethylformamide, ethyl alcohol, propylene carbide, and molten salts can be used in addition to ordinary water.

In the soft magnetic thin film of the present invention, Co, Fe, N
Cu, Cr, Sn, Rh, P
One or more elements selected from d, Mn, P, B, Zn, Sn, Pt and the like may be contained. Content is 3
It is preferable to be not more than wt%.

It should be noted that the film may contain trace amounts of C and S, but these materials have a great influence on the magnetic properties, and thus care must be taken. Specifically, both are 1000pp
m or less.

The soft magnetic thin film of the present invention is preferably provided with uniaxial anisotropy in a target direction. As a method for imparting uniaxial anisotropy, film formation in a magnetic field or annealing in a magnetic field after the film formation can be used. As the film formation in a magnetic field, a method of forming a film in a constant DC magnetic field is generally used. However, in the soft magnetic thin film of the present invention, the anisotropic magnetic field Hk is often too large, and in order to obtain high magnetic permeability, it is often required to optimize Hk. As a method of optimizing Hk, a method of forming a film in an orthogonal magnetic field, annealing in a rotating magnetic field, or making the magnetic field directions in film formation in a DC magnetic field and annealing in a DC magnetic field in-plane orthogonal is effective. Film formation in an orthogonal magnetic field can be performed by generating a magnetic field with a coil and applying a current alternately. Further, when a permanent magnet is used, it becomes possible by rotating the cathode by 90 °. Since the saturation magnetostriction value often increases in the positive direction during annealing, it is preferable to form a film so that the saturation magnetostriction value after annealing becomes a desired value. In order to reduce Barkhausen noise of the thin film magnetic head, it is necessary to keep the saturation magnetostriction value of the soft magnetic thin film at a small negative value. For this purpose,
The film is designed to have a slightly large negative magnetostriction during film formation and a small negative value after annealing. It is also effective to perform the in-plane orthogonal magnetic field application heat treatment a plurality of times to control the anisotropy to improve the magnetic permeability and control the magnetic domain structure.
By making the magnetic domain structure suitable, it is possible to reduce Barkhausen noise when a device is formed.

In the present invention, the fcc phase and a small amount of b
The cc phase may be co-deposited, but it is difficult to co-deposit a small amount of bcc phase in the above composition range. Therefore, usually, after forming an fcc single phase thin film, a small amount of bcc phase is deposited by heat treatment. Preferably. The annealing in a magnetic field described above can be used for this heat treatment.
The holding temperature during the heat treatment is preferably from 240 to 370.
° C, more preferably 280-350 ° C. If the heat treatment temperature is too low, the bcc phase does not precipitate.
The amount of phase precipitation becomes too large, and the coercive force increases. The heat treatment time is preferably from 0.1 to 10 hours.

The thickness of the soft magnetic thin film of the present invention may be appropriately determined according to the purpose, and is not particularly limited. To obtain a low coercive force, the thickness is usually about 0.5 to 10 μm. The thickness is preferably about 0.5 to 4.5 μm when applied to a thin film magnetic head, and about 3 to 7 μm when applied to a thin film transformer.

The soft magnetic thin film of the present invention can be applied to various magnetic devices in addition to a thin film magnetic head and a thin film transformer. Further, applications utilizing low coercive force and large magnetostriction (λs) are expected.

[0048]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

Example 1 A substrate having a thickness of 50 A made of titanium and 500 A made of permalloy by sputtering was used on a Corning 7059 glass having a thickness of 10 mm × 10 mm × 0.7 mm. 1N-hydrochloric acid (normal temperature) as plating pretreatment
After immersion for 30 seconds and washing with water, a soft magnetic thin film sample was formed under the following plating conditions. As a sample for measuring a saturated magnetostriction value, a substrate obtained by separately treating a glass plate having a thickness of 0.1 mm and performing the same treatment as the above substrate was used.

An auxiliary cathode made of a copper plate was provided around the substrate in the plating bath. The overall shape of the cathode was a 3 inch disk, and a 4 inch diameter TiPt plate was used for the anode. A paddle having a triangular cross section was used for stirring, and paddle stirring was performed at a position 2 mm from the cathode at a cycle of 60 times / minute. The plating solution had the following composition, and the total amount was about 7 liters.

Plating bath composition (per liter) Cobalt sulfate heptahydrate 0-20 g Nickel sulfate hexahydrate 0-50 g Ferrous sulfate heptahydrate 0-20 g Boric acid 25 g Ammonium chloride 15 g Saccharin 2 g Surface activity Agent trace

The plating bath temperature was 40 ° C., the plating bath pH was 2.8, the current density was 1.5 A / dm ² , the plating time was 5 minutes, and electroplating was performed while applying a DC magnetic field of 300 Oe. A soft magnetic thin film sample having a thickness of 1.2 μm was obtained.
In this case, various compositions were obtained by changing the concentration ratio of metal ions in the bath. In addition, for some samples, a 2 kOe magnetic field was applied in the film plane and in a direction perpendicular to the magnetic field application direction during film formation at a temperature of 300 ° C. in a vacuum heat treatment furnace for the purpose of anisotropic magnetic field control. Annealing was performed for 30 minutes.

The following measurement was performed for each of the obtained samples.

(Composition) The composition was measured using a fluorescent X-ray analyzer and ICP.

(Coercive force Hc) Measured at 60 Hz with an AC BH tracer.

(Saturation magnetic flux density Bs) Measured by VSM.

(Saturation magnetostriction value)
It was measured in a magnetic field of 0 Oe.

(Permeability) 5 MHz by the figure 8 coil method,
It was measured at 3 mOe.

(X-ray diffraction) Cu-Kα ray (50 kV, 40
mA) was used to determine the peak intensity of each surface.

FIG. 1 shows a sample selected to explain the relationship between the crystal phase and the plane orientation ratio and Hc. From FIG. 1, it can be seen that when fcc is single-phase and I (200) / I (111) is 0.1 to 0.2, Hc is 0.5 Oe or less in all cases, and almost 0.1 Oe or less in 0.15 or more. It can be seen that Hc of On the other hand, the sample in which the bcc phase is mixed and the sample in which I (200) / I (111) is less than 0.1 have a high Hc. Note that, in FIG. 1, all the samples having I (200) / I (111) of 0.1 to 0.2 have the composition in the area ABCD in FIG.
In these samples, the bcc phase is (110)
This was confirmed by the appearance of diffraction peaks on the (211) plane, the (211) plane, and the (211) plane. In FIG. 1, what is indicated as fcc + bcc is I (110) / I (111)> 0.1. In FIG. 1, what is indicated as fcc is I (1
10) / I (111) = 0.

FIGS. 2 and 3 show samples selected for explaining the relationship between the composition and Hc. In the ternary composition diagram of FIG. 2, samples having Hc of 0.3 Oe or less are plotted, and among the samples plotted in FIG. Plotted. FIGS. 2 and 3 also plot samples of Co = 0, which are permalloy compositions and Bs
Was as low as less than 10 kG. On the other hand, the sample of the present invention, which is a three-component system, had an extremely high Bs of 13 to 20 kG.

Detailed characteristics of an example of the sample of the present invention plotted in FIG. 3 are shown below.

Film composition Co = 40 wt%, Fe = 28 wt%
, Ni = 32 wt% crystalline phase fcc phase + bcc phase plane orientation ratio I (200) of the trace / I (111) = 0.19, I
(110) / I (111) = 0 Magnetic properties after annealing Hc = 0.05 Oe, Bs = 17
kG, Hk = 5 Oe, μ = 3500 The bcc phase has an accelerating voltage of 200 kV and a limited visual field of 5 μm
Was confirmed by electron diffraction.

The C content in the above sample was 850 ppm,
The S content was 550 ppm.

<Example 2> Co = 38 wt%, Fe = 28
A thin film sample containing wt% and Ni = 34 wt% was formed in the same manner as in Example 1. Next, annealing was performed at the holding temperature shown in Table 1. The annealing conditions other than the holding temperature were the same as in Example 1. X for each sample after annealing
Line diffraction was performed, and I (200) / I (111) and I (200)
(110) / I (111) was determined, and electron beam diffraction was performed to examine the presence or absence of the bcc phase. The conditions for X-ray diffraction and electron beam diffraction were the same as in Example 1. Further, the Hc of these samples was measured. For comparison, the same measurement was performed on a sample that was not subjected to annealing. Table 1 shows the results.

[0066]

[Table 1]

From Table 1, it can be seen from the X-ray diffraction that I (110)
/ I (111) = 0, and it is determined that the phase is fcc single phase, it can be seen from electron beam diffraction that fcc + bcc can be confirmed. It can be seen that when the bcc phase exists and I (110) / I (111) ≦ 0.1, an extremely low Hc can be obtained.

[0068]

According to the present invention, a soft magnetic thin film having a low Hc and a high Bs can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing the dependence of Hc on the crystal phase and the plane orientation ratio.

FIG. 2 is a ternary composition diagram showing a range of a film composition from which low Hc can be obtained.

FIG. 3 is a ternary composition diagram showing a range of a film composition from which a low Hc can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yuichi Sato 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-1-8605 (JP, A) JP-A-2 -68906 (JP, A) JP-A-62-160708 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25D 3/00-7/12 G11B 5/31-5/325 H01F 10/00-10/30 H01F 41/14-41/28

Claims (5)

(57) [Claims] 1. aCo-bNi-cFe [where a,
b and c represent the ratios (wt%) of Co, Ni and Fe, respectively, satisfying the following relationships: a = 28 to 75 wt%, b = 16 to 60 wt%, c = 9 to 42 wt%, and a + b + c = 100 wt% I do. Having a composition represented by the following formula, and mainly having a face-centered cubic phase, and at least two phases having different crystal structures in which a body-centered cubic phase is confirmed by electron diffraction. Soft magnetic thin film. 2. The soft magnetic thin film according to claim 1, wherein said soft magnetic thin film is heat-treated after said film formation. 3. The soft magnetic thin film according to claim 2, wherein the temperature of the heat treatment is 240 to 370 ° C. 4. The soft magnetic thin film according to claim 1, wherein the sulfur content in the film is 1000 ppm or less. 5. A magnetic inductive MR head having the soft magnetic thin film according to claim 1.