JP2006013549A - Control method for magnetic anisotropy of magnetic thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soft magnetic thin film that shows high permeability and low loss in high-frequency waves and that can be effectively applied to a surface magnetic element, such as a surface inductor and surface transformer. <P>SOLUTION: The main feature of the control method for the magnetic anisotropy of a magnetic thin film are as follows. First, a magnetic thin film and protective layer are formed on a substrate. Then, thermal treatment is carried out, while impressing magnetic field in parallel with the film surface of the foregoing magnetic thin film. As a result, the amount of local anisotropic dispersion is made very small. After that, thermal treatment is carried out, while impressing magnetic field perpendicularly to the film surface of the foregoing magnetic thin film. Finally, induced magnetic anisotropy containing components in the film surface is introduced unparallely to the film surface of the magnetic thin film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a soft magnetic thin film used for planar magnetic elements such as planar inductors and planar transformers.

  In recent years, various electronic devices have been actively miniaturized. However, downsizing of the power supply unit of electronic equipment is delayed compared with that. For this reason, the volume ratio which a power supply part occupies for the whole apparatus is only increasing. The downsizing of electronic equipment is largely due to the use of LSIs for various circuits, but such miniaturization and integration of magnetic parts such as inductors and transformers that are essential for the power supply unit have been delayed, which is the main reason for the increase in volume ratio. It has become.

  In order to solve this problem, a planar magnetic element in which a planar coil and a magnetic body are combined has been proposed, and studies on its performance have been advanced. Magnetic thin films used for these magnetic elements are required to have high magnetic permeability and low loss in a high frequency region of 1 MHz or higher. Further, in order to design an optimum magnetic element, a thin film whose magnetic permeability is controlled to a specific value is required. These requirements are common to other magnetic elements such as thin film magnetic heads.

  In the high frequency region, the magnetic permeability is mainly provided by the rotational magnetization process. For this reason, excitation in the hard axis direction is important, and high-frequency permeability and high-frequency loss in the hard axis direction are important physical properties. The high-frequency magnetic permeability is a quantity that is intricately related to various physical properties of the sample, and the one having the highest correlation includes the anisotropic magnetic field and the amount of local anisotropic dispersion. The high-frequency magnetic permeability changes approximately in proportion to the reciprocal of the anisotropic magnetic field, and decreases as the amount of anisotropic dispersion increases.

  Conventionally, various methods have been studied in order to obtain a magnetic film having a controlled anisotropic magnetic field. For example, a method that uses shape anisotropy by processing a film into a specific shape, a method that uses a substructure such as a columnar structure by oblique deposition, etc., preferential orientation obtained by substrate selection and film formation condition control There are a method using the magnetocrystalline anisotropy of a film or an epitaxially grown film, a method using lamination or a combination with different types of magnetic materials, a method using film formation in a magnetic field or a heat treatment in a magnetic field, or a method combining these.

  Among these, as the heat treatment in a magnetic field, a direct-current magnetic field heat treatment method in which a magnetic field is applied in one direction in the film surface, a rotating magnetic field heat treatment method in which the magnetic field direction is rotated in the film surface, and the like are known. The DC magnetic field heat treatment method is a method for inducing uniaxial anisotropy while preventing the magnetic domains from sticking. The heat treatment method in a rotating magnetic field is a method for reducing the in-plane anisotropy of the sample. These heat treatments are particularly effective for controlling magnetic anisotropy in a system in which structural anisotropy is induced according to the theory of directional ordered arrangement.

  However, the following problems occur when trying to realize high magnetic permeability and low loss of the magnetic thin film by these methods.

  The magnetic anisotropy imparted by the heat treatment in the in-plane DC magnetic field is mainly determined by the temperature of the heat treatment and does not depend positively on the magnitude of the applied magnetic field. In general, the magnitude of this anisotropy is a value inherent to the sample and decreases with an increase in the heat treatment temperature, so that the controllability of the anisotropic magnetic field is not good. Especially in the amorphous system where the crystallization temperature is lower than the Curie temperature, it is difficult to make the magnetic anisotropy smaller than the magnetic anisotropy just below the crystallization temperature, and it is impossible to cope with the case where higher magnetic permeability is required. There is. Even in amorphous systems where the relationship between crystallinity, Curie temperature and crystallization temperature is reversed, when applied to magnetic elements such as thin-film inductors and magnetic heads, restrictions such as the heat resistance temperature of materials other than magnetic materials Therefore, a low anisotropic magnetic field corresponding to a desired high permeability may not be achieved.

  Heat treatment in a rotating magnetic field is a method that can reduce the macroscopic anisotropy before the heat treatment to zero in principle. In that respect, the controllability of the anisotropic magnetic field is superior to the heat treatment in the in-plane DC magnetic field. In reality, in many cases, a desired high-frequency magnetic permeability is obtained by controlling an anisotropic magnetic field by appropriately combining in-plane DC magnetic field heat treatment and rotating magnetic field heat treatment. However, in this method, when exciting at a high frequency in the macroscopically hard axis direction, there is a possibility that the microscopically local excitation is in the easy axis direction, resulting in deterioration of high frequency characteristics and an increase in loss. May be invited. In addition, high frequency characteristics may be impaired by local anisotropic dispersion distributed in the plane.

  As described above, a magnetic element compatible with miniaturization requires a soft magnetic material having high permeability and low loss, and a soft element that achieves both low loss and a small anisotropic magnetic field within a limited temperature range. It is required to obtain a magnetic thin film with good controllability.

  An object of the present invention is to provide a soft magnetic thin film in which in-plane anisotropic magnetic field is easily controlled in a limited temperature range, and anisotropy is induced that enables high permeability and low loss at high frequencies. It is to provide.

  The method for controlling the magnetic anisotropy of a magnetic thin film according to the present invention comprises forming a magnetic thin film and a protective film on a substrate, performing a heat treatment while applying a magnetic field parallel to the film surface of the magnetic thin film, After the amount of dispersion is extremely small, heat treatment is performed while applying a magnetic field in a direction perpendicular to the film surface of the magnetic thin film, and induced magnetic anisotropy containing in-film components non-parallel to the film surface of the magnetic thin film. It is characterized by introducing sex.

  The magnetic thin film that is the subject of the present invention is a soft magnetic thin film that does not have a substructure such as a columnar structure and that can induce structural anisotropy according to a directional ordered array.

  According to the present invention, it is possible to provide a soft magnetic thin film exhibiting high magnetic permeability and low loss at high frequencies, and can be effectively applied to planar magnetic elements such as planar inductors and planar transformers.

Hereinafter, the present invention will be described in more detail with reference to FIGS. FIG. 1A is a perspective view showing a soft magnetic thin film having an easy magnetization axis in a direction forming an angle β with respect to the film surface, and FIG. 1B is a view showing polar coordinates of magnetization vectors. 2A is an explanatory diagram showing the direction of the magnetization vector I, and FIG. 2B is an explanatory diagram showing the direction of the effective magnetic field. In these figures, K ₀ is a uniaxial anisotropic energy of induced magnetic anisotropy by heat treatment in a magnetic field, I is a magnetization vector, H _d is a demagnetizing field, H _ex is an external magnetic field, and H _eff is an effective magnetic field. In FIG. 1A, K ₀ is expressed as a vector parallel to the easy axis direction.

In a system that does not have a three-dimensional anisotropic structure such as a columnar structure and can induce structural anisotropy according to the theory of directional ordered arrangement, as shown in FIGS. The easy axis direction of magnetic anisotropy induced by heat treatment in a magnetic field or film formation in a magnetic field coincides with the direction of the magnetization vector I at the time of heat treatment or film formation. Further, as shown in FIGS. 2A and 2B, the direction of the magnetization vector I is substantially the same as the direction of the effective magnetic field H _eff . As shown in FIG. 2B, the effective magnetic field H _eff is a vector composition of the external magnetic field H _ex and the demagnetizing field H _d . Here, H _d = −I sin φ / μ ₀ . Therefore, there is a difference in the magnitude of the induced magnetic anisotropy energy constant K ₀ regardless of whether the direction of the effective magnetic field H _eff is parallel to, perpendicular to the film surface, or an intermediate inclined direction. The direction of the easy axis of magnetization is parallel to the direction of the effective magnetic field H _eff .

As shown in FIG. 2B, a DC magnetic field sufficiently larger than the demagnetizing field H _d is applied as the external magnetic field H _{ex in} the direction of the angle α with respect to the film surface or the substrate surface. In contrast, when heat treatment or film formation is performed so that an effective magnetic field H _eff is generated in the direction of angle β, induced anisotropy due to structural anisotropy is formed in the direction of angle β with respect to the film surface. The difference between α and β approaches zero as the external DC magnetic field H _ex is larger than the demagnetizing field H _d . However, in a soft magnetic material that generates a magnetic field induced directional ordered array and has sufficient saturation magnetization, the effect of shape anisotropy is generally larger than that of induced anisotropy. Can obtain a soft magnetic thin film whose in-plane is an easily magnetized surface. Therefore, the in-plane easy axis direction is preserved in the initial in-plane anisotropy easy axis direction.

The in-plane uniaxial anisotropy constant K _pl in which the easy axis of magnetization is induced in the direction of the angle β with respect to the film surface can be derived as follows. Here, as shown in FIG. 1B, the magnetic anisotropy energy E ₀ when the magnetization vector I is in the direction (θ, φ) can be expressed as a function of the direction of the magnetization vector I as follows.

Considering the in-plane magnetic anisotropy, θ = π / 2 is always established, and therefore equation (1) can be written as follows.

As is clear from the equation (2), K ₀ cos ² β in parentheses acts as an in-plane apparent uniaxial magnetic anisotropy constant, and the direction of θ = 0, π is the easy axis direction of magnetization. . That is, the x-axis direction in the figure is the easy magnetization axis direction, and the in-plane uniaxial anisotropy constant K _pl = K ₀ cos ² β.

Among these, a case where heat treatment or film formation is performed in a DC magnetic field in a direction perpendicular to the film surface will be described with reference to FIG. In FIG. 3, it is assumed that the in-plane magnetic anisotropy K _pl is induced by the prior in-plane DC magnetic field heat treatment (which may be caused by the film formation method). Further, K _pd represents magnetic anisotropy by heat treatment in a DC magnetic field in a direction perpendicular to the film surface, and e _DO represents an easy magnetization axis of induced magnetic anisotropy by directional ordered arrangement.

Similar to the discussion above, when a sufficiently large DC magnetic field is applied as the external magnetic field _Hex compared to the demagnetizing field _Hd in the direction perpendicular to the film surface, the induced anisotropy due to the structural anisotropy is perpendicular to the film surface. Formed in any direction. For this reason, even if the in-plane magnetic anisotropy exists due to the directional regular arrangement resulting from the pre-in-plane DC magnetic field heat treatment, the in-plane anisotropy decreases as the heat treatment time elapses. This is because the magnetic anisotropy is a regularity parameter of the directional regular arrangement, and the regularity in the film surface decreases as the regularity in the direction perpendicular to the film surface grows. As shown in FIG. 3, ideally, the anisotropy in the film plane can be reduced to 0 by performing heat treatment for a time sufficient to reach the equilibrium state. Therefore, the magnitude of the in-plane anisotropy can be controlled by controlling the heat treatment time.

As described above, the in-plane uniaxial anisotropy constant K _pl = K ₀ cos ² β in the magnetic thin film of the present invention. Therefore, as shown in FIG. 4, by changing the angle β formed between the direction of easy magnetization of the induced magnetic anisotropy by the directional regular array and the film surface from π / 2 to 0, apparent uniaxial magnetism in the plane is obtained. soft magnetic thin film which is controlled from the anisotropy energy K _pl is 0 to K ₀ is obtained. Regarding the angle β, even a simple experimental device can be set to a desired value with sufficiently good accuracy. This indicates that a film in which magnetic anisotropy is induced non-parallel to the film surface can realize a smaller in-plane anisotropic magnetic field than a film in which magnetic anisotropy is induced parallel to the film surface. means.

This effect can also be shown as shown in FIG. This figure shows the control range of the magnitude of the in-plane magnetic anisotropy energy for the magnetic thin film according to the present invention and the conventional magnetic thin film. In this figure, the minimum value of the uniaxial anisotropy energy introduced parallel to the surface due to the structural anisotropy according to the directional ordered arrangement when the heat treatment in the direct current magnetic field is performed in the film surface is represented by K _0min . . On the other hand, the control range of the magnitude | size of the induced magnetic anisotropy energy in the surface of the soft-magnetic thin film which has a magnetization easy axis | shaft of induction magnetic anisotropy non-parallel to the film surface based on this invention is shown. It can be seen that the present invention can cope with smaller in-plane anisotropy and can cope with higher magnetic permeability.

  Next, consider a case where the magnetic thin film is excited at a high frequency in the in-plane hard axis direction. In the heat treatment process for obtaining the magnetic thin film of the present invention, no effective magnetic field is generated in the in-plane hard axis direction. This means that, from a statistical mechanical point of view, the local microscopic easy magnetization axis is very unlikely to be generated parallel to the macroscopic in-plane magnetization hard axis direction. Further, in the present invention, unlike the heat treatment in the rotating magnetic field, since there is almost no dispersion of the original induced magnetic anisotropy orientation, the amount of local anisotropy dispersion can be made extremely small.

  FIG. 6 schematically shows the frequency characteristics of the real part and imaginary part of the complex permeability. In this figure, the solid line represents the magnetic thin film of the present invention, and the broken line represents the magnetic thin film that has been heat-treated in a rotating magnetic field. The imaginary part of the complex permeability is an amount proportional to the loss per loop. As shown in FIG. 6, even in the case of a soft magnetic thin film that macroscopically shows the same in-plane anisotropic magnetic field, the present invention can realize a lower loss than that subjected to heat treatment in a rotating magnetic field. .

  As described above, according to the present invention, an in-plane anisotropic magnetic field can be controlled by heat treatment or film formation in a DC magnetic field that is not parallel to the film surface, and a minute in-plane corresponding to a desired high permeability can be controlled. A magnetic thin film having an anisotropic magnetic field and having anisotropic dispersion removed can be obtained. As a result, high magnetic permeability and low loss can be realized when high-frequency excitation is performed in the hard axis direction.

  Examples of the present invention will be described below.

  In the following examples and comparative examples, samples made of an amorphous CoZrNb thin film produced by an RF magnetron sputtering method were used. The main film forming conditions are as follows.

-Target: Co ₈₄ Zr _6.2 Nb _9.8 (casting composition), 3 inch diameter-Substrate rotation speed: 19.5 rpm
Substrate: amorphous SiO ₂ (thermal oxidation, 0.8 μm thickness) / Si wafer (100), 5 inch diameter Substrate temperature: 39 to 55 ° C.
・ Achieving vacuum: 1-3 × 10 −4 Pa
Sputtering conditions RF power: 10.5 W / cm ²
Atmosphere: Ar flow (0.20 Pa)
Deposition time: 68 min
Under the above conditions, a CoZrNb thin film having a thickness of 2.0 μm was obtained. Subsequently, amorphous SiO ₂ (1 μm thick) was immediately laminated as a protective film with the same apparatus without breaking the vacuum. The saturation magnetization of this sample was 1.0 T at 20 ° C. and 0.6 T at 450 ° C. The crystallization temperature of this sample was 500 ° C.

Example 1
The sample was subjected to heat treatment in a vacuum by applying a DC magnetic field in the direction of an angle α (α = 30 °, 45 °, 60 °, 65 °, 70 °, 75 °, 90 °) with respect to the film surface. . As the heat treatment apparatus, a vibrating sample magnetometer (manufactured by Toei Kogyo Co., Ltd., trade name VSM-5) was used. The magnetometer is used by utilizing an electromagnet (maximum applied magnetic field 20 kOe) attached to the apparatus, and a magnetization vector film by an external magnetic field larger than a strong demagnetizing field (6 to 10 kOe) in a direction perpendicular to the film surface. This is to control the angle β with respect to the surface. The applied magnetic field was 15 kOe, the heat treatment temperature was 450 ° C., and the heat treatment time was 10 min.

Example 2
The sample was vacuum-sealed in a quartz tube, and heat treatment was performed by applying a DC magnetic field of 2 kOe parallel to the film surface. The heat treatment temperature was 450 ° C. By this heat treatment, the anisotropic dispersion immediately after film formation is removed, and an amorphous CoZrNb thin film in which uniform uniaxial magnetic anisotropy is induced in the plane is obtained.

  This sample was heat-treated in a vacuum using the same apparatus as in Example 1 while applying a DC magnetic field perpendicular to the film surface. The applied magnetic field was 13 kOe, the heat treatment temperature was 350 ° C., 400 ° C. or 450 ° C., and the heat treatment time was 10 min.

Comparative Example 1
Using the same apparatus as in Example 1, the sample was heat-treated in an in-plane DC magnetic field. At this time, the heat treatment temperature was variously changed from 350 ° C. to just below 500 ° C. which is the crystallization temperature of the sample. Other conditions are the same as those in the first embodiment.

Comparative Example 2
Using the same apparatus as in Example 1, the sample was heat-treated in an in-plane DC magnetic field. Other conditions are the same as those in the first embodiment. Thereafter, in-plane rotating magnetic field heat treatment was performed in a vacuum atmosphere using a rotary magnetic field heat treatment furnace manufactured by Naruse Kagaku Kikai. The in-plane applied magnetic field was 0.3 kOe, the rotation speed was 100 rpm, and the heat treatment temperature was variously changed from 350 ° C. to 500 ° C.

  Hereinafter, the result of examining the characteristics of these magnetic thin films will be described.

  First, for the magnetic thin film of Example 2, after the first stage in-plane DC magnetic field heat treatment, the magnetization curves were measured in the in-plane easy axis direction and the hard axis direction, respectively. FIG. 12 shows a magnetization curve in the hard axis direction, and FIG. 13 shows a magnetization curve in the easy axis direction. Each figure shows two types of magnetization curves of applied magnetic fields of 10 Oe and 250 Oe. The horizontal axis is an externally applied magnetic field display. These are full-loop magnetized ring lines, but since the coercive force is very small, little reciprocal hysteresis is observed. It should be noted that a magnetic field of 2 Oe is required to be almost saturated even in the easy axis direction, which is due to the influence of the demagnetizing field. The in-plane anisotropic magnetic field can be evaluated from the difference between the saturation magnetic fields in these two directions, and it can be seen that a good soft magnetic thin film is obtained.

  FIG. 7 shows the dependence of the in-plane anisotropic magnetic field Hk on the applied magnetic field angle α during the heat treatment for the magnetic thin film of Example 1. As is clear from this figure, the in-plane anisotropic magnetic field Hk decreases as the angle α increases. FIG. 8 is a re-display of FIG. 7 with the horizontal axis representing the effective magnetic field angle during heat treatment, that is, the angle β of the easy axis of magnetic anisotropy formed during heat treatment with respect to the film surface. In this figure, theoretical predicted values are also shown with broken lines. The measured value of the dependence of the in-plane anisotropic magnetic field Hk on the angle β is in good agreement with the theoretically predicted value. From this, it is understood that the anisotropic magnetic field in the film surface can be well controlled by the heat treatment in the DC magnetic field that is not parallel to the film surface.

  FIG. 9 shows the dependence of the coercive force Hc in the in-plane hard axis direction on the angle α of the magnetic thin film of Example 1. From this figure, it can be confirmed that the coercive force does not deteriorate in the soft magnetic thin film in which the easy magnetization axis is induced in a direction non-parallel to the film surface. In particular, the soft magnetic thin film obtained under the condition of α = 90 ° C. has a very small coercive force of 1 mOe or less.

  FIG. 10 shows the dependency of the high-frequency permeability imaginary part μ ″ on the high-frequency permeability real part μ ′ when the magnetic thin films of Example 1 and Comparative Example 2 are excited in the hard axis direction at a frequency of 10 MHz. In the figure, the solid line is Example 1, and the broken line is Comparative Example 2. This figure also shows calculated values of eddy current loss predicted from values such as resistivity and film thickness. As is apparent from this figure, the loss in Example 1 is smaller than that in Comparative Example 2, and there is almost no influence of hysteresis loss other than eddy current loss and other abnormal losses. From this, it can be confirmed that in the system in which the induced magnetic anisotropy inclined to the film surface according to the present invention is imparted, good magnetization difficult axis excitation is performed.

  Next, using the soft magnetic thin film (β = 50 °) of Example 1 and the soft magnetic thin film (β = 0 °) of Comparative Example 1 having induced magnetic anisotropy parallel to the film surface, thin film inductors were respectively formed. Produced. FIG. 11 shows the frequency characteristics of the inductance L and quality factor Q of these thin film inductors. In the figure, the solid line is Example 1, and the broken line is Comparative Example 1. As is clear from this figure, in Example 1, higher L is obtained than in Comparative Example 1, and no deterioration of Q is recognized.

  FIG. 14 shows the heat treatment temperature dependence of the in-plane anisotropic magnetic field Hk for the magnetic thin films of Example 2 (after two-step heat treatment) and Comparative Example 1. In the figure, the solid line is Example 2, and the broken line is Comparative Example 1. Although an in-plane anisotropic magnetic field Hk tends to decrease with increasing heat treatment temperature, Example 2 has a smaller in-plane anisotropic magnetic field than Comparative Example 1.

  FIG. 15 shows the heat treatment temperature dependence of the coercive force Hc in the in-plane hard axis direction for the magnetic thin films of Example 2 (after two-step heat treatment) and Comparative Example 2. In the figure, the solid line is Example 2, and the broken line is Comparative Example 2. In Example 2, Hc decreases as the heat treatment temperature increases. On the other hand, in Comparative Example 2, Hc increases as the heat treatment temperature increases. When an ideal single magnetic domain is excited in the hard axis direction, no coercive force is generated in the rotational magnetization process. Therefore, it is estimated that the increase in coercive force in Comparative Example 2 corresponds to an increase in the amount of local anisotropic dispersion.

  14 and 15, it can be seen that in Example 2, the in-plane anisotropic magnetic field can be reduced while avoiding an increase in coercive force.

  FIG. 16 shows the dependence of tan δ on the high-frequency permeability real part μ ′ when the magnetic thin films of Example 2 (after two-stage heat treatment) and Comparative Example 2 are excited in the hard axis direction at a frequency of 10 MHz. In the figure, the solid line is Example 2, and the broken line is Comparative Example 2. As is apparent from this figure, the loss in Example 2 is smaller than that in Comparative Example 2. Further, in Comparative Example 2, hysteresis loss at high frequencies is increased due to the increase in the coercive force described above.

  In the above embodiment, heat treatment is performed after the magnetic thin film is formed. However, by forming the magnetic thin film in a DC magnetic field that is non-parallel to the substrate surface, an easy magnetization axis that is non-parallel to the film surface is formed. May be.

(A) is a perspective view which shows the magnetic thin film which has a magnetization easy axis in the direction which makes angle (beta) with respect to the film surface based on this invention, (b) is a figure which shows the polar coordinate display of a magnetization vector. (A) is explanatory drawing which shows the direction of a magnetization vector, (b) is explanatory drawing which shows the direction of an effective magnetic field. Explanatory drawing which shows the change of the direction of the easy axis of magnetization of induced magnetic anisotropy by a directional regular arrangement with time passage when heat-treating in a DC magnetic field in a direction perpendicular to the film surface of the magnetic thin film. Shows the dependence on the effective field angle β during the heat treatment of K _pl / K ₀ for magnetic thin film according to the present invention. The figure which shows the control range of the magnitude | size of an in-plane magnetic anisotropy energy about the magnetic thin film which concerns on this invention, and the magnetic thin film heat-processed in the conventional in-plane DC magnetic field. The figure which shows the frequency characteristic of the real part and imaginary part of a complex magnetic permeability about the magnetic thin film which performed the magnetic thin film which concerns on this invention, and the conventional heat processing in an in-plane rotating magnetic field. The figure which shows the dependence with respect to the applied magnetic field angle (alpha) at the time of the heat processing of the in-plane anisotropic magnetic field Hk about the magnetic thin film of Example 1. FIG. The figure which shows the dependence with respect to the effective magnetic field angle (beta) at the time of the heat processing of the in-plane anisotropic magnetic field Hk about the magnetic thin film of Example 1. FIG. The figure which shows the dependence with respect to the applied magnetic field angle (alpha) of the coercive force Hc of the in-plane hard magnetization direction about the magnetic thin film of Example 1. FIG. The figure which shows the dependence with respect to the high frequency magnetic permeability real part μ 'of the high frequency magnetic permeability imaginary part μ' 'at the time of exciting the magnetic thin film of Example 1 and Comparative Example 2 in the hard axis direction at a frequency of 10 MHz. The figure which shows the frequency characteristic of the inductance L and quality factor Q of the thin film inductor produced using the magnetic thin film of Example 1 and Comparative Example 1. FIG. The figure which shows the magnetization curve of the hard-magnetization-axis direction after the 1st step heat processing about the magnetic thin film of Example 2. FIG. The figure which shows the magnetization curve of the magnetization easy axis direction after the 1st step heat processing about the magnetic thin film of Example 2. FIG. The figure which shows the heat processing temperature dependence of the in-plane anisotropic magnetic field Hk about the magnetic thin film of Example 2 and Comparative Example 1. FIG. The figure which shows the heat processing temperature dependence of the coercive force Hc of the in-plane hard axis direction about the magnetic thin film of Example 2 and the comparative example 2. FIG. The figure which shows the dependence with respect to the high frequency magnetic permeability real part (mu ') of tan-delta at the time of exciting in the hard-axis direction at a frequency of 10 MHz about the magnetic thin film of Example 2 and Comparative Example 2. FIG.

Claims (2)

  A magnetic thin film and a protective film are formed on a substrate, and heat treatment is performed while applying a magnetic field in parallel to the film surface of the magnetic thin film to reduce the amount of local anisotropy extremely, and then the film surface of the magnetic thin film is formed. Magnetic anisotropy of a magnetic thin film characterized in that heat treatment is performed while applying a magnetic field in a vertical direction to introduce induced magnetic anisotropy including in-film components non-parallel to the film surface of the magnetic thin film. Sex control method.   2. The method for controlling magnetic anisotropy of a magnetic thin film according to claim 1, wherein the magnetic thin film is an amorphous magnetic thin film.

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