JPH02302007A - Magnetic head manufacturing method - Google Patents

Abstract

PURPOSE:To easily control an easy axis of magnetization and an anisotropic magnetic filed by a method wherein, while a magnetic field is being applied in such a way that a uniaxial magnetic anisotropy is in a direction nearly orthogonal to a desired easy axis of magnetization, a heat treatment is executed and, after that, while the magnetic field is being applied in a direction nearly parallel to the desired easy axis of magnetization, the heat treatment is executed. CONSTITUTION:When a magnetic field is applied in a direction perpendicular to an easy axis of magnetization and a heat treatment is executed, an anisotropic magnetic field is reduced with an increase in time when the holding time is smaller than t1 or t1'. In this case, the easy axis of magnetization conserves an initial direction 3. When the holding time becomes larger then t1 or t1', the anisotropic magnetic field is increased with an increase in the holding time. The easy axis of magnetization is a direction of an arrow 4 and becomes parallel to a magnetic-field application direction 2. Consequently, when this is applied to a magnetic head, it is required to set that the direction 4 corresponds to a desired easy axis of magnetization. In this case, a heat treatment must be executed in a magnetic field in order to set the easy axis of magnetization to a direction orthogonal to the desired direction in a previous stage.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic head using an amorphous magnetic alloy as a magnetic core material, and particularly relates to a method of manufacturing a magnetic head using an amorphous magnetic alloy as a magnetic core material. 'rJ is a method of manufacturing a magnetic head that can
[Prior Art] In general, in amorphous magnetic alloys, the origin of magnetic anisotropy is the directional ordered arrangement of magnetic atoms, and its behavior upon heat treatment in a unidirectional magnetic field is The following is known.

■As the heat treatment temperature increases, the anisotropic magnetic field decreases and the magnetic permeability increases. ■When heat treatment is performed under the same conditions, the anisotropic magnetic field increases as the saturation magnetic flux density increases, resulting in permeability. While the magnetic flux decreases, the crystallization temperature of amorphous magnetic alloys decreases with increasing saturation magnetic flux density.

As explained above, when heat treatment is performed in a unidirectional magnetic field, the lower limit of the anisotropic magnetic field or the upper limit of magnetic permeability is
determined by the crystallization temperature). As the saturation magnetic flux density increases, the lower limit of the anisotropic magnetic field increases and the upper limit of magnetic permeability decreases.

When an amorphous magnetic alloy with a high saturation magnetic flux density is used as a magnetic core material, this situation causes a decrease in reproduction efficiency due to insufficient magnetic permeability, which poses a serious problem for magnetic heads. For example, communication technical report MR8
4-52 (1984), a method is known in which heat treatment is performed in a rotating magnetic field to impart magnetic anisotropy.

[Problem to be solved by the invention]

Although the method of heat treatment in a rotating magnetic field described above has the advantage of being able to obtain a small anisotropic magnetic field or a large magnetic permeability without being restricted by the crystallization temperature, it has the following problems. 〇■ It is difficult to control the axis of easy magnetization and the anisotropic magnetic field, and the reproducibility is poor.

■ Mass production is poor because the sample is rotated.

In particular, the above problem (■) is a fatal problem for magnetic heads. In other words, as is well known, it is necessary to impart magnetic anisotropy to the magnetic core so that the direction of magnetic flux propagation is the direction of maximum magnetic permeability. Therefore, it is necessary that the direction of the axis of easy magnetization is perpendicular to the direction of magnetic flux propagation, and controlling this direction is an equally or more important factor than increasing magnetic permeability. Furthermore, in the completed state of the magnetic head, it is necessary to take into account the disturbance of the axis of easy magnetization due to the inverse magnetostriction effect. It is necessary to take this into consideration and control the anisotropic magnetic field to an optimal value. However, the above-described method of imparting magnetic anisotropy by performing heat treatment in a rotating magnetic field has a major problem in that it is difficult to control the axis of easy magnetization and to control the anisotropic magnetic field to an optimum value.

Therefore, the technical problem to be solved by the present invention is to solve the above-mentioned problems of the prior art. The purpose of this invention is to provide a method for manufacturing the same.

[Means to solve the problem]

The above objects of the present invention are: In a method of manufacturing a magnetic head using a magnetic core made of an amorphous magnetic alloy having uniaxial magnetic anisotropy, the uniaxial magnetic anisotropy applies a magnetic field approximately perpendicular to the desired axis of easy magnetization. The first step is to perform heat treatment while applying the magnetization, and then the second step is to perform heat treatment while applying a magnetic field in the direction substantially parallel to the desired axis of easy magnetization. This is achieved by

[Effect]

The operation of the present invention will be explained using the second example and FIG. 3. FIG. 2 is a diagram for explaining the magnetic field application direction, easy magnetization axis direction, etc. when an amorphous magnetic alloy is heat treated in a unidirectional magnetic field. In the figure, 1 is an amorphous magnetic alloy material;
2 is an arrow indicating the direction of magnetic field application, 3 is an arrow indicating the initial easy axis direction of magnetization, and 4 is an arrow indicating the easy axis direction of magnetization after heat treatment in a magnetic field for a sufficiently long time. Figure 3 is a graph showing the relationship between the heat treatment holding time in a unidirectional magnetic field and the anisotropic magnetic field. In the figure, 5 represents the relationship between the holding time at a high heat treatment temperature and the anisotropic magnetic field. Irf characteristic line 6 is a characteristic line showing the relationship between holding time and anisotropic magnetic field at low heat treatment temperature, which is the result when heat treatment is performed by applying a magnetic field sufficient to saturate magnetization. It is shown. In addition,
A negative anisotropy field corresponds to when the easy axis direction coincides with arrow 3, i.e. the initial easy axis direction, and a positive anisotropy field corresponds to when the easy axis direction coincides with arrow 4, i.e. This corresponds to the case where the magnetic field application direction 2 coincides with the magnetic field application direction 2.

As shown in FIGS. 2 and 6, when heat treatment is performed by applying a magnetic field in a direction perpendicular to the axis of easy magnetization, the holding time is tl or 1. In this case, the direction of the easy axis of magnetization maintains the initial direction 5. In this case, the anisotropic magnetic field decreases with increasing time. However, when the holding time exceeds tl or 1,/, the anisotropic magnetic field increases with increasing holding time. In this case, the easy axis direction of magnetization is the direction of arrow 40, which is parallel to the magnetic field application direction 2.

As shown in Figure 3, the rate of change of the anisotropic magnetic field is large when the holding time is short, approaches 0 (zero) K as the holding time increases, and then decreases as the heat treatment temperature increases. In Fig. 5, for example, if the anisotropic magnetic field is increased to 1
Let us consider the case where it is controlled to 1.5. As shown in the figure, the same anisotropic magnetic field is applied at a high heat treatment temperature for a holding time t2 to t3, and at a low heat treatment temperature t4 to t3.
, obtained in both cases. The difference between the two is
The difference in the easy axis direction of magnetization is that the former is orthogonal to the direction of the applied magnetic field, and the latter is parallel. Furthermore, as is clear from the figure, (tz~15)<<(14~ts), and the retention time margin of the latter is significantly larger than that of the former. This shows that the latter condition is more suitable than the former as a method of controlling the desired anisotropic magnetic field. Therefore, when applied to a magnetic head, direction 4 is the one that facilitates the desired magnetization. It is necessary to set it so that it corresponds to the axial direction. In this case, it is necessary to perform heat treatment in a magnetic field in order to set the direction of the axis of easy magnetization perpendicular to the desired direction in the previous step (◇), then perform heat treatment in a unidirectional magnetic field in the following two steps. As a result, the direction of the axis of easy magnetization and the magnitude of the anisotropic magnetic field can be controlled with good reproducibility.

First step: Heat treatment is performed by applying a magnetic field in a direction perpendicular to the desired axis of easy magnetization.

Second step: A magnetic field is applied in a direction parallel to the desired axis of easy magnetization, and heat treatment is performed.

In addition, compared to the heat treatment temperature of the first stage (first step),
The lower the heat treatment temperature in the second stage (second step) and the larger the difference, the smaller the rate of change of the anisotropic magnetic field with respect to the holding time, and the greater the holding time margin. The present invention is illustrated in FIG. 1 and will be explained based on the nine actual flows. FIG. 1 schematically shows the relationship between the magnetic head and the direction of magnetic field application during heat treatment in a magnetic field.

In the figure, 11 is a non-magnetic ceramic member (4!!
Part thickness: ltmm), 12 is CoNbZr amorphous magnetic alloy thin film (saturation magnetic flux density: 195Tll!I thickness 20μ
m), 13 is a medium sliding surface, 14 is a nonmagnetic gap material (thickness 213 μm) made of S i 02 film, 15 is a winding window, and the CoN'bZr amorphous magnetic alloy thin film 12 is made nonmagnetic. The cores, which are arranged and formed like a sandwich between the ceramic members 11, are joined, and the CoNbZ
r The amorphous magnetic alloy thin film 12 constitutes a closed magnetic path, and an operating gap is formed at the front ◇ Also, 16
indicates the desired axis of easy magnetization, 17 indicates the direction of magnetic field application during the first stage of heat treatment in a magnetic field, and 18 indicates the direction of magnetic field application during the second stage of heat treatment in a magnetic field.

After processing the head into the shape shown in Figure 1, first, the magnetic field strength R: *
The first step of heat treatment in a magnetic field was performed under the conditions of oxoe + temperature [: 430° C. and holding time: 30 minutes].

Then magnetic field strength zoKOee temperature = 400°C.

A second stage heat treatment in a magnetic field was performed under conditions of a holding time of 81 hours.

A coil was wrapped around a magnetic head that had been heat-treated in a two-step unidirectional magnetic field as described above, and the head electromagnetic conversion characteristics were evaluated, and the results showed that the characteristics varied compared to a conventional magnetic head that was heat-treated in a rotating magnetic field. The width is small and the regeneration efficiency is 1~
An improvement of 2aB was observed.

In addition, in the above-mentioned example, heat treatment in a magnetic field was performed in the final step after forming the magnetic head shape, but it does not necessarily have to be done in the final step, and the same effect may be obtained even if it is performed in an intermediate step. Needless to say, it is also possible to apply various shapes of the magnetic head, materials of the amorphous magnetic alloy, etc. other than those of the embodiments.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reproducibly and stably control the axis of easy magnetization and the magnitude of the anisotropic magnetic field, and the magnetism made of the seeded crystalline magnetic alloy is In a morale head using a core, the effect that contributes to improving its characteristics is remarkable.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing the magnetic field heat treatment process of a magnetic head according to an embodiment of the present invention, and FIG. 2 shows the direction of magnetic field application and magnetization when an amorphous magnetic alloy is heat treated in a unidirectional magnetic field. An explanatory diagram showing the easy axis direction, and FIG. 6 is an explanatory diagram showing a graph of the relationship between the heat treatment holding time in a unidirectional magnetic field and the anisotropic magnetic field.0 1...Amorphous magnetic alloy material, 2...Arrow indicating the direction of magnetic field application, 3...Arrow indicating the initial easy axis direction of magnetization, 4
...Arrow indicating the axis of easy magnetization after heat treatment in a magnetic field for a sufficiently long time, 5...Characteristic line showing the relationship between holding time at high heat treatment temperature and anisotropic magnetic field, 6... Characteristic line showing the relationship between holding time and anisotropic magnetic field at low heat treatment temperature, 11...Nonmagnetic ceramic member, 12...C
oNbZr amorphous magnetic alloy thin film, 15... Medium sliding surface, 14... Nonmagnetic gap material, 15... Winding window,
16... Arrow indicating the desired axis of easy magnetization, 17...
An arrow indicating the direction of magnetic field application during the first stage magnetic field heat treatment,
1B...An arrow indicating the direction of magnetic field application during the second stage magnetic field heat treatment. Agent: Patent Attorney Katsuo Ogawa, 1., 2) Niri + 1:1lJth Ceramic Parts, 12:Co
11bZr non! iS1% combination t'*a13-Amu hood ♂ moving surface, 14:1 gourd ■ main gear soft) end +5:4 for Ujutsu @,
16:7 arrow indicating direction of axis, 17:
In the magnetic field of the 11th flame, the pressure of the 1st chapter of the Bogin territory is 1 uniformity, and the size is v4.
Daji L 18: 2nd fmcn, Kinutu Shimanaka Ryo Me V! θH
Ri4f one side arrow showing the leap. Figure 2 Otsu No. 51 yen]

Claims (4)

[Claims] 1. A method for manufacturing a magnetic head using a magnetic core made of an amorphous magnetic alloy having uniaxial magnetic anisotropy, characterized in that the uniaxial magnetic anisotropy is imparted by multiple heat treatments in a unidirectional magnetic field. A method of manufacturing a magnetic head. 2. 2. The magnetic field heat treatment step according to claim 1,
A first step of performing heat treatment while applying a magnetic field in a direction substantially perpendicular to the desired axis of easy magnetization, and then heat treatment while applying a magnetic field in a direction substantially parallel to the direction of the desired axis of easy magnetization. A method of manufacturing a magnetic head, comprising: a second step of performing. 3. 3. The method of manufacturing a magnetic head according to claim 2, wherein the heat treatment temperature in the first step is higher than the heat treatment temperature in the second step. 4. 3. The method of manufacturing a magnetic head according to claim 2, wherein the heat treatment time in the first step is shorter than the heat treatment time in the second step.