JP2002338339A - Method for manufacturing oxide magnetic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an oxide magnetic material which can heighten return loss and can reveal excellent electric wave absorbing performance even at high frequency band. SOLUTION: The ferrite powder of MnZn base, NiZn base, MgZn base or the like and nonmagnetic powder (industrial potter's clay) which contains silica, alumina, alkali or the like and is measured at a prescribed amount are dry blended by a blender so as to attain a prescribed blending ratio to manufacture blended powder. Molding pressure is applied to the blended powder to mold a prescribed shape, then obtained molding is fired at a set top temperature for a prescribed time in air or in an atmosphere to manufacture a sintered compact. Obtained sintered compact is processed to a prescribed shape to manufacture an oxide magnetic material. The sintered compact can heighten return loss to >=20 dB at a broad band extending from several tens MHz to several GHz by adjusting thickness, for example, and can be favorably used as an electric wave absorber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oxide magnetic material, and more specifically, to a method of absorbing radio waves by mixing a ferrite powder with a non-magnetic powder such as silica, alumina, or an alkali. The present invention relates to an improvement in a method of manufacturing an oxide magnetic material for improving and improving characteristics.

[0002]

BACKGROUND OF THE INVENTION Ferrite materials such as MnZn-based, NiZn-based, and MgZn-based are used, for example, in various cores. Further, such a ferrite material may be applied to a magnetic tile, a radio wave absorber and the like.

However, when the radio wave absorption characteristics (reflection attenuation) are evaluated, the return loss can be increased in a relatively low frequency band with the conventional ferrite-based magnetic material, and the preferable characteristics as a radio wave absorber can be obtained. When the frequency band is high, the return loss becomes low, and it cannot be applied to a radio wave absorber in such a frequency band.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to solve the above-mentioned problems, to increase the return loss even in a high frequency band, and to obtain good radio wave absorption characteristics. An object of the present invention is to provide a method for producing an oxide magnetic material that can be expressed.

[0005]

In order to achieve the above-mentioned object, a method of manufacturing an oxide magnetic material according to the present invention comprises mixing a ferrite powder with a non-magnetic powder containing silica, alumina and alkali. Then, a mixed powder was produced, then granulated and conditioned, then molded and fired.

According to the results obtained from the experimental results, as described above, silica, alumina,
The sintered body made by mixing non-magnetic powder containing alkali, granulating, conditioning, molding, and sintering has the characteristics of the mixed materials interacting with each other, and has a high return loss even in a high frequency band. It was confirmed that good radio wave absorption characteristics could be exhibited.

The ferrite powder contains 50% Fe ₂ O _3.
~ 58 mol%, MnO is 12 ~ 47 mol%, ZnO is 3
To 30 mol%. This range is M
This is a range in which high characteristics can be obtained as nZn-based ferrite.

In this case, the firing is preferably performed at a temperature of 900 to 1200 ° C. in the air or the atmosphere. 1200
If the temperature exceeds ℃, the sample will melt and lose its shape,
If the temperature is lower than 900 ° C., the strength and various properties of the sintered body cannot be sufficiently obtained, so that the above-mentioned temperature range is preferable.

Further, the ferrite powder is made of Fe ₂ O ₃
43 to 50 mol%, ZnO 10 to 35 mol%, Cu
The composition may be such that O is 3 to 15 mol% and the balance is NiO. This range is a range in which high characteristics can be obtained as the NiZn-based ferrite.

In this case, the calcination is carried out at a temperature of 800 in the atmosphere.
It is good to carry out at １1100 ° C. If the temperature exceeds 1100 ° C., the sample melts and the shape cannot be maintained. If the temperature is lower than 800 ° C., the strength and various properties of the sintered body cannot be sufficiently obtained.

As another composition, the ferrite powder contains 46 to 49 mol% of Fe ₂ O _{3 and} 24 of MgO.
２７27 mol%, ZnO 18２１21 mol%, MnO 4
A composition of about 7 mol% and CuO of 1 to 4 mol% may be employed. This range is a range in which high characteristics can be obtained as the MgZn-based ferrite.

In this case, the firing is carried out at 900 ° C. in the atmosphere.
It is good to carry out at -1200 ° C. If the temperature is higher than 1200 ° C., the sample is melted and the shape cannot be maintained. If the temperature is lower than 900 ° C., the strength and various properties of the sintered body cannot be sufficiently obtained.

On the other hand, the particle diameter of the ferrite powder is 1
It is good to be 000 μm or less. Most of the particle diameter of the ferrite powder containing the aggregate is 1000 μm or less,
If the particle size is larger than this, it is crushed to flatten the
This is because it is necessary to perform classification.

Further, the nonmagnetic powder has a silica component of 3%.
It is preferable that the composition is 0 to 85 wt%, the alumina component is 10 to 45 wt%, and the alkali component is 5 to 25 wt%.
That is, when the alumina component exceeds the above range, the moldability deteriorates, and when the alumina component falls below the range, the strength decreases. The same applies to the silica component. Further, when the alkali component exceeds the above range, the strength decreases, and when the alkali component is below the range, the firing temperature increases and the energy cost spent for firing increases. Therefore, the above range is preferable.

In order to lower the firing temperature, MgO, C is used as the alkali component constituting the non-magnetic powder.
aO, K ₂ O, and Na ₂ O are preferably used. Furthermore, the particle diameter of the non-magnetic powder is preferably 500 μm or less.
That is, if it exceeds 500 μm, the kneadability when mixed with the ferrite powder is reduced, resulting in poor moldability.

The non-magnetic powder preferably contains an organic binder in an amount of 0.1% by weight or more. That is, by mixing the non-magnetic powder, molding can be performed without an organic binder, but the inclusion of the binder improves the bonding during molding. More preferably, the content is about 1 to 2% by weight. Note that, when the content is increased, the organic binder flies at the time of firing, so that the number of cavities generated in the sintered body increases. Therefore, in order to produce a porous sintered body, it is preferable to increase the content (2 wt% or more). In addition, as the non-magnetic powder that satisfies the above-described conditions, for example,
There is industrial clay.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. First, as a first embodiment of the present invention,
An example of a method for manufacturing an oxide magnetic material using a MnZn-based ferrite material will be described.

First, a MnZn ferrite powder (FDK)
A predetermined amount of nonmagnetic powder is weighed and dry-mixed with a mixer to obtain a predetermined mixing ratio. Thereby, a mixed powder is produced. Non-magnetic powder
Industrial clay containing silica, alumina and alkali.

Next, a pressure 2 for forming the mixed powder
Ton / cm ² is added to form a toroidal ring shape, and thereafter, sintering is performed at a top temperature of 1100 ° C. for 1 hour in the air to produce a sintered body. Then, the obtained sintered body was toroidally shaped (outer diameter: 7 mm, inner diameter: 3 mm,
(Thickness: 3 mm) to produce a sample (oxide magnetic material).

In order to demonstrate the effects of the above manufacturing method, various samples were manufactured under different manufacturing conditions, and the high frequency characteristics of each sample were measured. Specifically, a coaxial tube (outer diameter: 7 mm, inner diameter: 3 mm) serving as an S-parameter measurement jig and a vector network analyzer are used. Then, with the sample set in the coaxial tube, 30 MHz to 6 GHz
The S ₁₁ (complex reflectance) and S ₂₁ (complex transmittance) parameters are measured in the frequency band of z, and from these values, the material constant of the sample, that is, the complex relative permeability (μ _r ) and the complex relative permittivity (ε _r) ). Next, the obtained material constants are substituted into the following equations (1) and (2) to obtain the return loss (Retur).
n Loss) was obtained, and the radio wave absorption characteristics were evaluated based on the return loss (RL).

[0021]

(Equation 1)

Next, the manufacturing conditions of the sample will be described.
Nonmagnetic powder (industrial clay) comprises a kaolin mineral _{(Al 2 O 3, 2SiO 2} · 2H 2 O) is a plastic component,
The crystal structure is a layered structure made of Al or Si ions. Further, it contains silica as a skeleton component for improving mechanical strength and a glass layer component for promoting porcelain formation and compaction at a high temperature.

Further, the non-magnetic powder contains 0.1 wt% or more of an organic binder. This is for improving the bonding property at the time of molding, and preferably contains, for example, about 1 to 2% by weight. The specific composition is as shown in Table 1 below. Here, three types of nonmagnetic powder a, nonmagnetic powder b, and nonmagnetic powder c were used by changing the composition ratio.

[0024]

[Table 1]

The three types of non-magnetic powder are hexagonal plate-like or flake-like particles each having a thickness and a diameter of several μm to several tens μm. Each of them has a particle size distribution (60 μm or less) shown in FIGS. The average particle diameter of the non-magnetic powder a shown in FIG. 1 was 10.9 μm, the non-magnetic powder b shown in FIG. 2 was 11.3 μm, and the non-magnetic powder c shown in FIG. 3 was 14.7 μm. Was.

The MnZn-based ferrite powder is composed of the basic components Fe ₂ O ₃ , MnO, and ZnO, and contains other minor components. The specific composition is 50 to 58 mol% of Fe ₂ O _{3, 12} to 47 mol% of MnO, ZnO
Is 3 to 30 mol%, and the particle diameter is 1000 μm or less.

As the mixed powder, the amount of the MnZn ferrite powder is 90 wt%, 80 wt%, 70 wt%.
%, 60 wt%, and 50 wt%.

The return loss of each sample was obtained as shown in FIGS. 4 to 6 show the experimental results (reflection attenuation characteristics) when the thickness was fixed at 20 mm and the amount of MnZn ferrite powder was changed as a parameter. In each figure, the HT21 material was manufactured by FDK Corporation. Is a conventional material. As is clear from the figures, the HT21 material is VH
While the return loss characteristics were excellent in the F band, it was confirmed that in each sample of the present embodiment, a return loss of 20 dB or more was obtained in the UHF band. In addition, it can be seen that by changing the mixing amount, the band of reflection attenuation (radio wave absorption) can be changed, and the radio wave absorption characteristics can be appropriately developed in a desired frequency band.

FIGS. 7 to 9 show the return loss characteristics when the mixing amount of the MnZn ferrite powder is fixed at 70 wt% and the thickness of the sample is changed as a parameter. As shown in the figure, the thickness of the sample is variable (1 cm).
５5 cm), it is possible to change the band of reflection attenuation (radio wave absorption) from several tens of MHz to several GHz,
It can be seen that the radio wave absorption characteristics can be appropriately developed in a desired frequency band.

As described above, according to the present invention, good radio wave absorption characteristics can be obtained in a high frequency band, and the radio wave absorption band can be appropriately set in a wide band. This is because the complex relative permeability of ferrite powder and the complex relative permittivity of non-magnetic powder (industrial porcelain) containing a large amount of alkali components, and the properties of the compound reacted after firing express proper conditions. it is conceivable that.

Next, a second embodiment of the present invention will be described. In this embodiment, based on the first embodiment described above, the manufacturing conditions of the sintered body, that is, the sintering process is performed not in the atmosphere but in the atmosphere.

That is, similarly to the first embodiment, a MnZn-based ferrite powder (made by FDK Corporation: 7
A predetermined amount of the H10 material) and the nonmagnetic powder are weighed, and dry-mixed by a mixer to obtain a predetermined mixing ratio. This allows
Produce a mixed powder. The non-magnetic powder is an industrial clay containing silica, alumina, alkali or the like.

Next, a pressure 2 for molding the mixed powder
ton / cm ² , and formed into a toroidal ring shape.
C. for 1 hour to produce a sintered body.

At this time, as shown in FIG. 10, the atmosphere firing is performed at a top temperature of 110 ° C. at a temperature rate of 300 ° C./hr.
After heating to 0 ° C. and keeping the top temperature of 1100 ° C. for 1 hour, the temperature was set to return to room temperature at a temperature rate of 300 ° C./hr. The atmosphere is set at atmospheric temperature while the temperature is raised from room temperature to 600 ° C.
During the temperature increase, the atmosphere is set to an N ₂ + O ₂ atmosphere, and when the temperature is maintained at 1100 ° C., the atmosphere is set to a 4 to 14% Po ₂ atmosphere.
An atmosphere of N ₂ + O ₂ was used during the temperature decrease to 0 ° C., and the atmosphere was used during the temperature decrease from 900 ° C. to room temperature. Then, the obtained sintered body was toroidally shaped (outer diameter: 7 mm, inner diameter: 3 mm, thickness: 3
mm) to produce a sample (oxide magnetic material).

In order to demonstrate the effects of the above manufacturing method, various samples were manufactured under different manufacturing conditions, and the high frequency characteristics of each sample were measured. The procedure of this characteristic measurement is the same as that of the first embodiment, and the description is omitted.

The sample manufacturing conditions are the same as in the first embodiment. In other words, non-magnetic powder (industrial clay)
It contains silica, alumina, alkali and the like. As shown in Table 1, the silica component is 30 to 85 wt%, the alumina component is 10 to 45 wt%, the alkali component is 5 to 25 wt%,
The organic binder component has a composition of 0.1 to 2% by weight.

The MnZn ferrite powder contains 50 to 58 mol% of Fe ₂ O _{3, 12} to 47 mol% of MnO and 3 to 30 mol% of ZnO as basic components, and has a particle diameter of 1000 μm or less. And

The return loss of each sample is shown in FIGS.
Was obtained as shown. As a result, as shown in FIGS. 11 to 13, which are the experimental results when the mixing amount of the MnZn ferrite powder was changed, it was confirmed that each sample of the present embodiment had excellent radio wave absorption characteristics in the VHF band. Was.

FIGS. 14 to 16 are graphs showing the return loss characteristics when the thickness of the sample is changed. As shown in the figure, by varying the thickness of the sample (1 cm to 5 cm), the band of reflection attenuation (radio wave absorption) can be changed from the VHF band to the vicinity of the UHF band. Absorption characteristics can be appropriately developed.

Therefore, according to the present embodiment, similar to the first embodiment, good radio wave absorption characteristics can be obtained in a high frequency band, and the band setting of the radio wave absorption can be appropriately set in a wide band. It is.

Next, a third embodiment of the present invention will be described. This embodiment is an example of a method for manufacturing an oxide magnetic material using a NiZn-based ferrite material. The basic processing procedure is the same as that of the MnZn ferrite material.

First, as in the first embodiment, NiZn
A predetermined amount of a system ferrite powder (manufactured by FDK Corporation: L59 material) and a non-magnetic powder are weighed and dry-mixed by a mixer to obtain a predetermined mixing ratio. Thereby, a mixed powder is produced. The non-magnetic powder is an industrial clay containing silica, alumina, alkali or the like.

Next, a pressure 2 for molding the mixed powder was used.
Ton / cm ² is added to form a toroidal ring shape, and thereafter, sintering is performed at a top temperature of 1100 ° C. for 1 hour in the air to produce a sintered body. Then, the obtained sintered body was toroidally shaped (outer diameter: 7 mm, inner diameter: 3 mm,
(Thickness: 3 mm) to produce a sample (oxide magnetic material).

In order to demonstrate the effects of the above manufacturing method, various samples were manufactured under different manufacturing conditions, and the high frequency characteristics of each sample were measured. The procedure of the characteristic measurement is the same as that of the first embodiment, and the description is omitted.

The sample manufacturing conditions are the same as in the first embodiment. In other words, non-magnetic powder (industrial clay)
It contains silica, alumina, alkali and the like. As shown in Table 1, the silica component is 30 to 85 wt%, the alumina component is 10 to 45 wt%, the alkali component is 5 to 25 wt%,
The organic binder component has a composition of 0.1 to 2% by weight.

The NiZn ferrite powder contains 43 to 50 mol% of Fe ₂ O ₃ , 10 to 35 mol% of ZnO, and ₃ to 15 mol% of CuO as basic components.
The balance is NiO composition, and the particle size is 1000 μm.
It is as follows.

The return loss of each sample was obtained in the same manner as in the first embodiment. As a result, it was confirmed that in each sample of the present embodiment, a return loss of 10 dB or more was obtained in a band of several hundred MHz to several GHz.

Also, by changing the thickness of the sample,
You can change the band of return attenuation (radio wave absorption),
It has been confirmed that radio wave absorption characteristics can be appropriately expressed in a desired frequency band.

Therefore, similarly to the first embodiment, good radio wave absorption characteristics can be obtained in a high frequency band, and the radio wave absorption band can be appropriately set in a wide band.

Next, a fourth embodiment of the present invention will be described. This embodiment is an example of a method for manufacturing an oxide magnetic material using an MgZn-based ferrite material. The basic processing procedure is the same as that of the MnZn ferrite material.

First, as in the first embodiment, MgZn
A predetermined amount of a system ferrite powder (HD12 material manufactured by FDK Corporation) and a nonmagnetic powder are weighed and dry-mixed by a mixer to obtain a predetermined mixing ratio. Thus, a mixed powder is produced. The non-magnetic powder is an industrial clay containing silica, alumina, alkali or the like.

Next, a pressure 2 for molding the mixed powder was used.
Ton / cm ² is added to form a toroidal ring shape, and thereafter, sintering is performed at a top temperature of 1200 ° C. for 1 hour in the atmosphere to produce a sintered body. Then, the obtained sintered body was toroidally shaped (outer diameter: 7 mm, inner diameter: 3 mm,
(Thickness: 3 mm) to produce a sample (oxide magnetic material).

In order to demonstrate the effect of the above manufacturing method, various samples were manufactured under different manufacturing conditions, and the high frequency characteristics of each sample were measured. The procedure of this characteristic measurement is the same as that of the first embodiment, and the description is omitted.

The sample manufacturing conditions are the same as in the first embodiment. In other words, non-magnetic powder (industrial clay)
It contains silica, alumina, alkali and the like. As shown in Table 1, the silica component is 30 to 85 wt%, the alumina component is 10 to 45 wt%, the alkali component is 5 to 25 wt%,
The organic binder component has a composition of 0.1 to 2% by weight.

The MgZn-based ferrite powder contains 46 to 49 mol% of Fe ₂ O ₃ , 24 to 27 mol% of MgO, 18 to 21 mol% of ZnO, and MnO as basic components.
Is 4 to 7 mol%, CuO is 1 to 4 mol%, and the particle size is 1000 μm or less.

The return loss of each sample was obtained in the same manner as in the first embodiment. As a result, it was confirmed that in each sample of the present embodiment, a return loss of 10 dB or more was obtained in a band of several hundred MHz to several GHz.

By changing the thickness of the sample,
You can change the band of return attenuation (radio wave absorption),
It has been confirmed that radio wave absorption characteristics can be appropriately expressed in a desired frequency band.

Therefore, similarly to the first embodiment, good radio wave absorption characteristics can be obtained in a high frequency band, and the band setting of the radio wave absorption can be appropriately set in a wide band.

[0059]

As described above, in the method for manufacturing an oxide magnetic material according to the present invention, the MnZn-based, NiZn-based, MgZ
A non-magnetic powder (industrial porcelain) containing silica, alumina, alkali, or the like is weighed to a predetermined amount to an n-type ferrite powder to produce a mixed powder, and a molding pressure is applied to the mixed powder. It is formed into a predetermined shape, and then fired at a set top temperature for a predetermined time in the air or atmosphere to produce a sintered body. Therefore, the obtained sintered body (oxide magnetic material)
Is obtained by making the characteristics of the mixed materials interact with each other, so that the return loss can be made high even in a high frequency band, and good radio wave absorption characteristics are exhibited.

Further, the band of the radio wave absorption can be appropriately set in a wide band by making use of the characteristics of the mixed materials, and it can be preferably used as a radio wave absorber.

[Brief description of the drawings]

FIG. 1 is a graph showing a particle size distribution of a non-magnetic powder a.

FIG. 2 is a graph showing a particle size distribution of a non-magnetic powder b.

FIG. 3 is a graph showing a particle size distribution of a nonmagnetic powder c.

FIG. 4 is a graph showing the reflection attenuation characteristics of a sample (mixing amount variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder a and baking them in the air.

FIG. 5 is a graph showing the reflection attenuation characteristics of a sample (mixing amount variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder b and firing the mixture in the air.

FIG. 6 is a graph showing the reflection attenuation characteristics of a sample (mixing amount variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder c and firing the mixture in the air.

FIG. 7 is a graph showing the return loss characteristics of a sample (thickness variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder a and firing the mixture in the air.

FIG. 8 is a graph showing the reflection attenuation characteristics of a sample (thickness variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder b and firing the mixture in the air.

FIG. 9 is a graph showing the return loss characteristics of a sample (thickness variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder c and firing the mixture in the air.

FIG. 10 is a time chart for explaining operation conditions of atmosphere firing.

FIG. 11 is a graph showing the reflection attenuation characteristics of a sample (mixing amount variable) obtained by mixing an MnZn-based ferrite material and a non-magnetic powder a and firing in an atmosphere.

FIG. 12 is a graph showing the reflection attenuation characteristics of a sample (mixing amount variable) obtained by mixing a MnZn-based ferrite material and a non-magnetic powder b and firing in an atmosphere.

FIG. 13 is a graph showing the reflection attenuation characteristics of a sample (mixing amount variable) obtained by mixing an MnZn-based ferrite material and a nonmagnetic powder c and firing in an atmosphere.

FIG. 14 is a graph showing the reflection attenuation characteristics of a sample (thickness variable) obtained by mixing an MnZn-based ferrite material and a non-magnetic powder a and firing in an atmosphere.

FIG. 15 is a graph showing the reflection attenuation characteristics of a sample (thickness variable) obtained by mixing an MnZn-based ferrite material and a non-magnetic powder b and firing in an atmosphere.

FIG. 16 is a graph showing the reflection attenuation characteristics of a sample (thickness variable) obtained by mixing an MnZn-based ferrite material and a nonmagnetic powder c and firing in an atmosphere.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) C04B 35/26 L (72) Inventor Tetsushi Akiyama 5-36-11 Shimbashi, Minato-ku, Tokyo FD F-term (reference) in K.K. Co., Ltd.

Claims (12)

[Claims] 1. A ferrite powder comprising silica, alumina,
A method for producing an oxide magnetic material, comprising mixing a nonmagnetic powder containing an alkali to produce a mixed powder, then granulating and controlling the humidity, molding and firing. 2. The ferrite powder according to claim 1, wherein the Fe ₂ O ₃ is 5%.
2. A composition comprising 0 to 58 mol%, MnO of 12 to 47 mol%, and ZnO of 3 to 30 mol%.
3. The method for producing an oxide magnetic material according to item 1. 3. The ferrite powder according to claim 1, wherein the Fe ₂ O ₃ is 4%.
The method for producing an oxide magnetic material according to claim 1, wherein the composition is 3 to 50 mol%, ZnO is 10 to 35 mol%, CuO is 3 to 15 mol%, and the balance is NiO. 4. The ferrite powder according to claim 1, wherein the powder contains 4% Fe ₂ O _3.
6 to 49 mol%, MgO 24 to 27 mol%, ZnO 18 to 21 mol%, MnO 4 to 7 mol%, CuO 1
The method for producing an oxide magnetic material according to claim 1, wherein the composition has a composition of 4 mol% to 4 mol%. 5. The ferrite powder having a particle size of 100
The method for producing an oxide magnetic material according to claim 1, wherein the thickness is 0 μm or less. 6. The non-magnetic powder, wherein the silica component is 30 to
The method for producing an oxide magnetic material according to any one of claims 1 to 5, wherein the composition has a composition of 85 wt%, an alumina component of 10 to 45 wt%, and an alkali component of 5 to 25 wt%. 7. The alkali component is MgO, CaO,
K 2 _O, the production method of the oxide magnetic material according to any one of claims 1 6, characterized in that either Na 2 _O. 8. The non-magnetic powder has a particle diameter of 500 μm.
The method for producing an oxide magnetic material according to claim 1, wherein: 9. The non-magnetic powder according to claim 1, wherein the non-magnetic powder contains 0.1 wt% or more of an organic binder.
3. The method for producing an oxide magnetic material according to item 1. 10. The method for producing an oxide magnetic material according to claim 2, wherein the calcination is performed at a temperature of 900 to 1200 ° C. in the air or the atmosphere. 11. The sintering is carried out in the atmosphere at a temperature of 800 to 800.
The method for producing an oxide magnetic material according to claim 3, wherein the method is performed at 1100 ° C. 12. The sintering is performed in the atmosphere at a temperature of 900 to 900.
The method for producing an oxide magnetic material according to claim 4, wherein the method is performed at 1200 ° C.