JPH10188220A - Soft magnetic alloy thin film, magnetic head and magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a soft magnetic alloy plating film having high electric resistivity while maintaining a high saturation magnetic flux density and relatively low soft magnetostrictive constant by using a magnetic core material added with Cr, Mo, W, etc., for a Co-Ni-Fe alloy. SOLUTION: The electric resistivity of the soft magnetic alloy thin film formed by adding <=5wt.% at least one kind of the elements selected from Cr, Mo and W to a Cox Niy Fez alloy (65<=x<=85, 10<=y<=25, 5<=z<=25wt.%) may be enhanced up to about 60μΩcm while that saturation magnetic flux density of >=1.3T and the magnetostrictive constant of <=+20/10<7> are maintained. The soft magnetic alloy thin film is manufactured from a plating bath prepd. by adding <=0.7g/l, in total, Cr, Mo and W ions to a plating high bath contg. bivalent Co, Ni and Fe ions respectively at rations of 6 to 15g/l, 10 to 30g/l, 0.5 to 2.5g/l and contg. a stress relieving agent and surfactant. The thin film is applied as an upper magnetic pole 15 to the magnetic head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a soft magnetic alloy thin film, a magnetic head, and a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art In recent years, as the recording density of magnetic disk devices has increased, a thin film magnetic head capable of recording on a medium having a high coercive force has been required. For that purpose, it is necessary to use a material having a high saturation magnetic flux density and excellent high-frequency characteristics as a core material of the magnetic head. As a current thin-film magnetic head material, permalloy (78 wt% Ni-Fe alloy) is known, but since the saturation magnetic flux density is as low as 1.0 T and the electric resistivity is as low as about 20 μΩcm, eddy current loss is large. In addition, there is a problem that the recording magnetic field intensity in a high frequency region is reduced. Other materials include a Co-based amorphous material and Sendust (Fe-Al-Si alloy).
Amorphous materials are thermally unstable and Sendust is 500
Since a heat treatment of about ° C. is required, there is a problem in the magnetic head process, and it has not been put to practical use.

As disclosed in Japanese Patent Application No. Hei 7-16666, as a material having a high saturation magnetic flux density and a recording magnetic field strength which does not decrease at high frequencies, a material prepared by plating is used.
６０60 wt% Ni—Fe alloy. Ni-Fe alloys have a high saturation magnetic flux density of 1.4 T or more. Also,
Since the electric resistivity is as high as 30 μΩcm or more and the eddy current loss is small, the magnetic permeability at high frequencies is high. However, Ni
The -Fe alloy has a high magnetostriction constant of 50/10 ^7, and it is difficult to obtain a good magnetic domain structure due to stress when the core is formed.

Further, Japanese Patent Application Laid-Open Nos. 64-8605 and 62-2569
No. 89, JP-A-6-89422 or JP-A-4-43989, there are Co-Ni-Fe alloys of various compositions produced by plating. The Co—Ni—Fe plated alloy has a high saturation magnetic flux density, and the magnetostriction constant also becomes low depending on the composition. However, since the electric resistivity is low, the eddy current loss is large, and the magnetic permeability at a high frequency decreases.

JP-A-2-29095 or JP-A-2-290
No. 995 discloses that the Co composition is 2 in order to reduce magnetostriction.
Cr of less than 3 at% and Mo of less than 6 at% are added to a Co-Ni-Fe alloy of about 0 at%. However, the magnetostriction of these films is 50 to 70 even when Cr or Mo is added.
It is as high as / 10 ⁷ .

[0006]

A magnetic disk drive having a high magnetic recording density has a high saturation magnetic flux density,
In addition, it is necessary to use a thin film magnetic head using a material that does not reduce the recording magnetic field strength at high frequencies. Co _x Ni _y Fe _z alloy (65 ≦ x ≦ 85 produced by a plating method,
10 ≦ y ≦ 25, 5 ≦ z ≦ 25 wt%) has a high saturation magnetic flux density of 1.6 T or more and a magnetostriction constant of +20/10.
Relatively low at ⁷ or less. However, the electric resistivity is 20 μΩcm
Therefore, the eddy current loss increases and the magnetic permeability at high frequencies decreases.

[0007] The purpose of this study is to provide a solution to the problem of Co-Ni-Fe plating films.

[0008]

Means for Solving the Problems The present inventor conducted a sincere study on a magnetic core material in a thin-film magnetic head, and as a result, by adding Cr, Mo, W, etc. to a Co-Ni-Fe alloy, a high cost was obtained. The present inventors have found that a soft magnetic alloy plating film having a high electric resistivity can be obtained while maintaining a saturated magnetic flux density and a relatively low magnetostriction constant, and have completed the present invention.

That is, the amounts of divalent Co, Ni and Fe ions are 6 to 15 g / l, 10 to 30 g / l, and 0.1, respectively.
Co _x Ni _y Fe prepared from a plating bath obtained by adding a total of 0.7 g / l or less of Cr, Mo and W ions to a plating bath of 5 to 2.5 g / l and a stress relaxing agent and a surfactant.
_z alloy (65 ≦ x ≦ 85, 10 ≦ y ≦ 25, 5 ≦ z ≦ 25
wt%), a soft magnetic alloy thin film to which at least one element selected from Cr, Mo, and W is added in an amount of less than 5 wt% has a saturation magnetic flux density of 1.3 T or more and a magnetostriction constant of +
The electric resistivity is about 60μ while keeping 20/10 ⁷ or less.
Can be as high as Ωcm.

A thin-film magnetic head using a plated soft magnetic film containing Co-Ni-Fe as a main component exhibits high frequency characteristics. Further, by using the thin film magnetic head, a magnetic recording / reproducing apparatus having a high magnetic recording density can be obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.
This will be described more specifically with reference to the figures and tables.

(Example 1) 80% by weight of 0.1 μm thickness
A Co—Ni—Fe—Mo alloy was produced on a glass substrate on which a Ni—Fe electrode film was formed, using a plating bath shown in Table 1.

[0013]

[Table 1]

The plating conditions at the time of fabrication are as follows: pH: 3.
0, bath temperature 30 ° C., current density 15 mA / cm ² . At this time, the Co-Ni-
The composition of Fe was 71 wt%, 18 wt%, 11
wt%. The Mo composition was changed by the amount of sodium molybdate added.

FIG. 1 shows changes in saturation magnetic flux density and magnetostriction constant with respect to the amount of Mo added. As shown in the figure, the saturation magnetic flux density decreases as Mo is added, but the magnetostriction constant is almost constant. FIG. 2 shows a change in electric resistivity with respect to the amount of Mo added. The electric resistivity increases as the amount of Mo added increases. As described above, by increasing Mo, the electric resistivity increases while maintaining the low magnetostriction constant, but the saturation magnetic flux density decreases. In order for the saturation magnetic flux density to be 1.3 T or more, the Mo amount is preferably 5 wt% or less. Further, in order for the saturation magnetic flux density to be 1.6 T or more, the Mo amount is more preferably 2 wt% or less.

In this embodiment, the case where Mo is added has been described. However, similar effects can be obtained by using Cr and W.

(Embodiment 2) Using a method similar to that of Embodiment 1, a Co-Ni-Fe-X (X = M
(o, Cr, W) magnetic films were prepared. Table 2 shows the characteristics of these magnetic films.

[0018]

[Table 2]

As shown in the table, by adding Mo, Cr, and W, the saturation magnetic flux density was not greatly reduced.
Electric resistivity can be increased. FIG. 3 shows the frequency dependence of the magnetic permeability of these magnetic films. As shown, M
The addition of o, Cr, and W increases the magnetic permeability at high frequencies.

(Embodiment 3) Using the magnetic plating film shown in Embodiment 1, a recording / reproducing separation type head was manufactured. The structure of the magnetic head is shown below. FIG. 4 is a perspective view when a part of the magnetic head is cut. The portion where the magnetoresistive film 11 is sandwiched between the shield layers 12 and 13 functions as a reproducing head. The shield layer 13 also functions as the lower magnetic pole of the recording head, and the portion of the shield layer 13 and the upper magnetic pole 15 sandwiching the coil 14 functions as a recording head. Upper magnetic pole 15
Was manufactured using a frame plating method. In addition, the material of the upper magnetic pole is 72 wt% Co-16w described in Example 1.
A t% Ni-9wt% Fe-3wt% Mo magnetic film was used.
Cu was used for the electrode 17 of the magnetoresistive film 11.

Hereinafter, a method of manufacturing the head will be described.

A sintered body mainly composed of Al ₂ O ₃ .TiC was used as a substrate 16 for the slider. Permalloy (80 wt% Ni-Fe alloy) containing nitrogen formed by a sputtering method was used for the shield layers 12 and 13. The thickness of each magnetic film was as follows. Upper and lower shield layers 12, 13
Was 2.0 μm, the upper magnetic pole 15 was 3.0 μm, and the gap material between the layers was Al ₂ O ₃ formed by sputtering.
The thickness of the gap layer was 0.2 μm between the shield layer and the magnetoresistive element, and 0.4 μm between the recording magnetic poles. As the magnetoresistive film 11, a permalloy film having a thickness of 20 nm was used. Cu having a thickness of 1 μm was used for the coil 14.

Recording and reproduction were performed using the thin-film magnetic head described above. The medium is Co-C with a coercive force of 2500 Oe.
An r-Pt alloy was used. The spacing between the head and the medium was 45 nm. FIG. 5 shows that the recording current is 4
The change of the overwrite with respect to the recording frequency at 0 mA is shown. At the same time, for comparison, the results of using a Co-18 wt% Ni-9 wt% Fe film to which Mo was not added for the upper magnetic pole are also shown. As shown in the figure, Mo is added to Co-Ni-Fe.
In a magnetic head using a magnetic film to which is added, excellent overwrite characteristics of −40 dB or more are obtained even at a recording frequency of 90 MHz. This is probably because the magnetic head according to the present invention was used.

In the present embodiment, the upper shield layer 13 is formed by a sputtering method, but may be formed by a plating method.

(Embodiment 4) A magnetic disk drive was manufactured using the magnetic head of the present invention described in Embodiment 3. FIG. 6 is an explanatory diagram of the structure of the magnetic disk drive.

The recording layer of the magnetic recording medium 21 has 2500
A material made of a Co-Cr-Pt alloy having a coercive force of Oe was used. The track width of the recording head of the magnetic head 23 was 2.3 μm, and the track width of the reproducing head was 1.7 μm. The magnetic core material of the recording head in the magnetic head 23 has a higher resistance, a higher saturation magnetic flux density, and a better magnetic domain structure of the magnetic poles as compared with a recording head using a conventional permalloy. A corresponding magnetic disk device can be manufactured. The magnetic head of the present invention
This is effective for a magnetic recording / reproducing apparatus having a maximum recording frequency of 90 MHz or more.

[0027]

According to the present invention, Co _x N produced by an electroplating method.
i _y Fe _z alloy (65 ≦ x ≦ 80,15 ≦ y ≦ 25,8
≦ z ≦ 25 wt%), the electric resistivity can be increased while maintaining a high saturation magnetic flux density and a relatively low magnetostriction constant by adding 5 wt% or less of Mo, W, and Cr. By using a soft magnetic thin film produced by this plating method for a magnetic head, a recording head having a maximum recording frequency of 90 MHz or more can be produced. Further, by using the recording head, a high-performance magnetic recording / reproducing apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing changes in saturation magnetic flux density and magnetostriction constant with respect to the amount of Mo added to a Co—Ni—Fe alloy.

FIG. 2 is a graph showing a change in electric resistivity with respect to the amount of Mo added to a Co—Ni—Fe alloy.

FIG. 3 is a graph showing frequency characteristics of magnetic permeability in a Co—Ni—Fe film to which Cr, Mo, and W are added.

FIG. 4 is a perspective view of a magnetic head according to the present invention.

FIG. 5 is a graph showing overwrite characteristics with respect to a recording frequency in the magnetic head of the present invention.

FIG. 6 is a perspective view of the magnetic disk drive of the present invention.

[Explanation of symbols]

11 ... Magnetoresistance effect film, 12, 13 ... Shield layer, 14
... coils, 15 ... upper magnetic poles, 16 ... substrates, 17 ... electrodes.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shunichi Narumi 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. System Division

Claims (5)

[Claims] 1. A Co _x Ni _y Fe _z alloy (65 ≦ x ≦ 85,1
0 ≦ y ≦ 25,5 ≦ z ≦ 25 wt%), Cr, Mo, W
A soft magnetic alloy thin film to which at least one element selected from the group consisting of 5 wt% or less is added, and wherein the magnetic alloy thin film is produced by an electroplating method. 2. The method according to claim 1, wherein the divalent Co, Ni, F
e ion amount is 6 to 15 g / l, 10 to 30 g /
1, 0.5 to 2.5 g / l and a plating bath containing 0.7 g / l or less of Cr, Mo, and W ions in an electroplating bath containing a stress relaxing agent and a surfactant. Soft magnetic alloy thin film. 3. A lower magnetic film, formed on the lower magnetic film, having one end in contact with one end of the lower magnetic film, and the other end facing the other end of the lower magnetic layer via a magnetic gap. ,
An upper magnetic film forming a magnetic circuit, a thin-film magnetic head comprising a coil having a predetermined number of turns intersecting with a magnetic core through a film electrically insulated between the two magnetic films, wherein the upper magnetic layer and 2. The method according to claim 1, wherein at least one of the lower magnetic layers is formed of a material.
A thin-film magnetic head formed of the soft magnetic alloy thin film according to claim 2. 4. A composite magnetic head in which the thin-film magnetic head according to claim 3 and a magnetoresistive element are combined. 5. A magnetic recording / reproducing apparatus equipped with the thin-film magnetic head according to claim 3.