JPS58213860A - Heat treatment of amorphous magnetic film - Google Patents

Abstract

PURPOSE:To improve the soft magnetic characteristics of an amorphous magnetic film formed on a substrate, by heat-treating the film in a magnetic field applied in a prescribed direction and by further heat treating the film while rotating the magnetic field in the film. CONSTITUTION:An amorphous magnetic film whose crystallization temp. is below the Curie temp. is formed on the surface of a substrate 3, the substrate 3 is mounted on a heater 1 in a container 4, and the container 4 is evacuated. A stationary magnetic field is applied to the film from magnets 5 placed at the outside of the container 4 in the direction perpendicular to the direction in which the magnetic permeability is measured, and the film is heated from room temp. to 300 deg.C in 30min with the heater 1 and held for about 15min. The magnets 5 are then rotated through a yoke 6, and while applying a rotating magnetic field to the film, the film is slowly cooled from 300 deg.C to room temp. in about 60min to improve the soft magnetic characteristics of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heat treating an amorphous magnetic film.

Due to the recent development of liquid super-quenching method? It is hoped that an amorphous magnetic alloy with an IJ-bond shape can be obtained. These are 2 bases.
2. After heat treatment at a temperature below the crystallization temperature Tx, quenching in water near room temperature in a trench,
It is known that excellent soft magnetic properties can be obtained. However, depending on the material, there are amorphous magnetic alloys whose Tx is lower than Tc, and therefore cannot be subjected to the heat treatment described above. The inventor first annealed materials that satisfied the conditions of T x (T c
4), or (1) a combination of annealing in a magnetic field perpendicular to the ribbon surface and annealing in a rotating magnetic field (JP-A-56) On the other hand, unlike the liquid ultra-quenching method described above, vapor deposition and Research on forming an amorphous film on a substrate using a gas quenching method such as sputtering and using this as a composite material is also gaining momentum.However, since the materials generally used for the substrate are ceramic or glass, As in the case of the amorphous ribbon obtained by the liquid quenching method described above, it is not possible to quench it in water after heat treatment. If a substrate such as metal is used, it will not crack even if it is rapidly cooled, but peeling will occur easily due to the difference in thermal expansion coefficient between the substrate and the amorphous film. For devices in the high frequency range, it is preferable not to use metal materials for the substrate.Furthermore, since the film thickness is generally small, it is recommended to combine annealing in a magnetic field perpendicular to the film surface and annealing in a rotating magnetic field as described above. is difficult to adopt because the demagnetizing field coefficient becomes extremely steep in the direction perpendicular to the plane, and a magnetic field of the same magnitude as the saturation magnetization B8 of the amorphous magnetic film is required.
This is because it is not very practical.

Note that it is sufficient that the rotational speed of the rotating magnetic field is about 1 Or, p, m or more, and desirably about 10 Or, p, m from the viewpoint of the configuration of the apparatus.

The present invention aims to solve the above-mentioned problems and provide a heat treatment method that significantly improves the soft magnetic properties of an amorphous magnetic film formed on a substrate. In other words,
We have discovered that the soft magnetic properties can be significantly improved by applying a magnetic field in one predetermined direction and heat-treating the material, followed by in-plane heat treatment in a rotating magnetic field. The present invention is based on such knowledge.

The method of the present invention will be explained in detail below.

A device as shown in FIG. 1 that can rotate or fix a magnetic field within the plane of a film was fabricated, and heat treatment experiments were conducted. In the figure, 1 is a heater, 1' is its extraction electrode, 2 is a thermocouple, and 2' is its extraction electrode. This heater 1
A substrate 3 having an amorphous film formed on its main surface is placed thereon, and heat treatment is performed while reducing the pressure in a container 4 surrounded by a quartz tube with a vacuum pump. The external magnetic field is applied by magnet 5. The magnetic gap is 6 m, and sample 3 has 1000 in-plane
A magnetic field of 0e is applied. The magnet 6 is attached to the yoke 6, and by rotating the yoke 6 with a motor (not shown), a rotating magnetic field is applied within the sample surface. 7 is a circle.

Hereinafter, specific examples of the present invention and comparative examples will be explained.
The effects of the present invention are shown.

Comparative Example 1 Fe2 with a thickness of 3 μm was deposited on a glass substrate by the 5 Baco sputtering method.
An amorphous alloy b film having a composition of C083,514,5 (Tx=460°C, Tc: 550°C) was formed. This amorphous alloy film was subjected to 10 Torr in a stationary state.
A magnetic field was applied for 2 e minutes in a vacuum at 30° C. for heat treatment, and then the material was slowly cooled in a magnetic field at room temperature. The frequency characteristics of the magnetic permeability μ of the heat-treated film were measured. in this case,
There were two types of magnetic fields for measuring μ: 1 moe and 10 moe. Regarding the measurement direction, two types of measurements were conducted: an easy axis direction parallel to the magnetic field direction during annealing in a magnetic field, and a hard axis direction perpendicular to the magnetic field direction. The results are shown in FIG. In the figure, μ,
, (1), μyo00 is the measurement magnetic field level (1
mOe or 1°moe) and the measurement direction (parallel I or perpendicular) are indicated by subscripts.

It is clear from Figure 2 that the frequency characteristics of magnetic permeability μ [1), μ, 01 measured in the easy axis direction are generally poor, and that of magnetic permeability μ (1), μ, μ, 00 measured in the hard axis direction are generally poor. Although the frequency characteristics are good, the magnetic permeability is low. In addition, the magnetic permeability in the easy axis direction changes greatly depending on the measuring magnetic field, and there is a problem in that the initial magnetic permeability is particularly low.

Comparative Example 2 Thickness 2p fabricated on a glass substrate by sputtering method
An amorphous film having a composition of Fe Co Nb 2 83.6 14.5 m was formed. This amorphous film is heated to 1O-3Torr'
) Heat treatment was performed in vacuum at 30° C. for 20 minutes using the apparatus shown in FIG. 1 while rotating the magnetic field at 100 r, p, m, and then slowly cooled to room temperature while rotating with the magnetic field. Magnetic permeability μφ(1) of the heat-treated membrane.

The frequency characteristics of μφ00 are shown in FIG. 3 (the subscript φ means heat treatment in a rotating magnetic field, and the number in parentheses indicates the measured magnetic field (unit: moe)).

As is clear from Fig. 3, although the magnetic permeability is good at the time of f and high when the measured magnetic field is large, the initial permeability μφ(1
) was only slightly improved compared to Comparative Example 1, which is not sufficient.

Example 1 Next, the fixed magnetic field heat treatment method performed in Comparative Example 1 and Comparative Example 2
The same amorphous alloy film was heat treated by combining the heat treatment method in a rotating magnetic field performed in 7.

The pattern of the heat treatment method is shown in FIG.

Pattern A is from room temperature to 300℃ with a fixed magnetic field.
The temperature was raised over 30 minutes to 300°C, held at 300°C for 16 minutes, then the magnetic field was rotated for 15 minutes, and the magnetic field was rotated for 60 minutes to cool down to room temperature. However, pattern B is a pattern in which the application order of the fixed magnetic field and the rotating magnetic field is reversed in pattern A, that is, heat treatment is performed in the rotating magnetic field, further heat treatment is performed in the fixed magnetic field, and then cooling is performed. FIG. 5 shows the frequency characteristics of the magnetic permeability of the sample obtained by the heat treatment method of pattern A. In the figure, the subscript of magnetic permeability μ means exactly the same thing as above. As is clear from the figure, the samples heat-treated using a combination of a fixed magnetic field direction perpendicular to the permeability measurement direction and a rotating magnetic field have magnetic permeability μ↓, φ(1), μμ,
It can be seen that the φOQ is high, the frequency characteristics are good, and there is no dependence on the measured magnetic field, which is extremely excellent. On the other hand, when a fixed magnetic field in a direction parallel to the permeability measurement direction is used, the initial permeability is insufficient, and the frequency characteristics and measurement magnetic field dependence of magnetic permeability are also poor.

Next, when a heat treatment experiment was conducted using pattern B, almost the same results as shown in FIG. 6 were obtained. Further, similar experiments were conducted by changing the heat treatment temperature and heat treatment time in a rotating magnetic field and a fixed magnetic field. As expected, the longer the heat treatment time and the higher the heat treatment temperature, the more the characteristics of each heat treatment will be emphasized, and the results shown in Figure 5 emphasize this. It was found that the results approached those shown in FIG. 2 or 3 depending on the heat treatment.

Next, we investigated the dependence of the initial magnetic permeability, which is an important factor, on the measurement direction within the film plane. The heat treatment was carried out according to pattern A in FIG.
The test was conducted on an amorphous alloy film having a composition of b14.5. The initial magnetic permeability μ at 4 hours in the plane of this alloy film was measured using the angle θ between the magnetic field direction of heat treatment in a fixed magnetic field and the measurement direction as a parameter. The results are shown in FIG. 6 on page 9. As is clear from the figure, the magnetic permeability is high when the above-mentioned angle θ is in the range of 900° to 45°, and it can be seen that the angles θ should not be parallel to each other.

Example 2 Amorphous alloy films with a thickness of 2 pm having various crystallization temperatures Tx and Curie point Tc were subjected to heat treatment in a rotating magnetic field similar to Comparative Example 2 for comparison. , a total of 4 magnetic permeabilities of 1 m0e were measured.

The results are summarized in the table below.

The experimental results shown in the table show that the present invention is extremely effective particularly for amorphous alloy films in which Tc is higher than Tx.

10. As can be seen from the examples shown above, the present invention is an extremely effective heat treatment method for improving the characteristics of amorphous magnetic films.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the structure of a magnetic field heat treatment apparatus for carrying out the method of the present invention, FIGS. 2, 3, and 6.
The figure shows an amorphous alloy film F e 2 COs 3. esNb
14.5 is a diagram showing the frequency characteristics of magnetic permeability μ after various heat treatments, FIG. 4 is a diagram showing representative examples of treatment patterns based on the heat treatment method of the present invention, and FIG. 6 is a diagram showing the frequency characteristics of magnetic permeability μ after various heat treatments of the present invention. FIG. 2 is a diagram showing the dependence of magnetic permeability μ (4 layers, 1 m0e) on the measurement direction within the plane of an amorphous alloy film. 1... Heater, 3... Substrate on which the amorphous film is attached on the main surface, 4... Container, 6...
・Magnet, 6. River... 11 Rotatable yoke. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
For illustration Shira A O χ (MHz) Fig. 3 711i number (opening) Fig. 5 Me supervisor 1 he Gobetsu ≦ (ko (/bu H7) No. 6
Figure)': (4MH2,/IFθe) θ-45'/(1" tJ6 t
σσθ

Claims (1)

[Claims] (1) Heat treatment of an amorphous film formed on a substrate in a magnetic field fixed in one direction within the plane of the amorphous film at a temperature below its crystallization temperature, and rotation within the plane of the amorphous film. 1. A method for heat treatment of an amorphous magnetic film, characterized by carrying out heat treatment in a magnetic field in combination. Heat treatment method for magnetic film. heat treatment method.