JP2000191368A - Magnetic material for high-frequency and high-frequency irreversible circuit element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic material which has an extremely small δH value and embodies high electric resistance and arbitrary 4 πMs by specifying the ratio of the Y site and Fe site of YIG ferrite to a specific range and substituting a part of Fe with Mn or Al. SOLUTION: The composition is represented by formulas (3.01<=A<=3.08, 0<=B<=0.5, 0<=C<=0.009). The composition purity is preferably 99 to 99.99%, the relative sintering density 95 to 99.9% and the average crystal grain size 5 to 50 μm. As a result, δH is <=7 (Oe), more adequately <=5 (Oe) and the low- loss garnet magnetic material for high-frequencies having the high resistance of >=1010 (Ω/cm) in a room temp. is obtained. In addition, 4 πMs may be arbitrarily set within a range of 100 to 1800 gauss and the material having 4 πMs suitable for the use frequency is selectable. Further, the insertion loss of the irreversible circuit element for high-frequencies may be confined to <=-0.8 (db), more adequately <=-0.5 (db). This element is adequate for isolators, circulators, gyrators, or the like, in high-frequency circuits of microwaves, milliwaves, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a garnet-based magnetic material used for high-frequency circuit components such as microwaves and millimeter waves, and a high-frequency nonreciprocal circuit device manufactured using the same.

[0002]

2. Description of the Related Art In recent years, as seen in the market expansion of satellite communications and mobile communications, high-speed and high-density applications in the information and communication fields have been progressing, and higher frequencies have been used. As a magnetic material used at such a high frequency, the electrical resistivity is high,
A garnet-based magnetic material having a small loss at a high frequency has attracted attention. For high-frequency signal processing, there are non-reciprocal circuit elements such as isolators, circulators, and gyrators that use the gyromagnetic effect of a magnetic substance to transmit signals in only one direction. A system magnetic material is used.

A garnet-based magnetic material is usually used as a single crystal thin film or a polycrystalline sintered body. The single crystal is produced by using a single crystal of GGG (gadolinium, gallium, garnet) made by the pulling method as a substrate.
It is generally manufactured as a thin film at a temperature of about 900 ° C by the (Liquid Phase Epitaxy) method. Although the sample produced by this method has a small magnetic resonance half width ΔH, it is disadvantageous in that it takes too much time to produce a sample having a thickness such as used in an isolator or the like, and is expensive.

[0004] On the other hand, since the polycrystal is produced as a normal ceramic sintered body, ΔH is at least one order of magnitude larger than that of a single crystal, but a sample of any size can be easily produced and compared with a single crystal. It is much cheaper, and this polycrystal is used for circulators and isolators.

In general, the characteristics required for high frequency magnetic materials such as microwaves and millimeter waves have a predetermined saturation magnetization of 4πMs according to the frequency to be used, a high Curie temperature Tc, and a half-value of ferromagnetic resonance absorption. It is necessary that the width ΔH is small and the dielectric loss is small. Of these, ΔH is a value representing the magnetic loss, which has the greatest effect on the loss of the device and needs to be particularly reduced.

As such a garnet-based high-frequency magnetic material, YIG ferrite represented by the general formula of Y _A Fe _8-A O ₁₂ is used, but its production method is difficult and the stoichiometric composition Y ₂ O ₃ 37.5 mol%, even Fe ₂ O ₃ 62.5 mol% of the composition of (Y ₃ Fe ₅ O ₁₂₎ was estimated at 0.5 mol% results in heterogeneous phase, delta
H is said to be extremely large.

According to Japanese Patent Publication No. 60-55970, when the mixing ratios of the raw materials Y ₂ O ₃ and Fe ₂ O ₃ are 38.63 to 39.45 mol% and 61.37 to 60.55 mol%, respectively, that is, Y _A
It is shown that when Fe _8-A O ₁₂ (3.09 ≦ A ≦ 3.16), there is no foreign phase and the ferromagnetic resonance absorption half width ΔH can be reduced.

In Japanese Patent No. 2504273, a part of Fe is
It has been shown that extremely small ΔH can be realized by adding Co and Zr while substituting with Mn.

[0009]

However, garnet-based magnetic materials are not suitable for practical use due to the delicate composition of ΔH and the electric resistance value that affects the dielectric loss, and the relative sintering density and fluctuation of the average crystal grain size. It has the disadvantage that it becomes large enough to cause problems.

Further, it is difficult to adjust the saturation magnetization 4πMs to an arbitrary value in accordance with the frequency to be used without deteriorating ΔH or electric resistance. Could not be satisfied.

[0011]

SUMMARY OF THE INVENTION The present invention _{is, Y A Fe 8-A O} 12
In the YIG ferrite represented by the general formula, the ratio of the Y site to the Fe site is fixed to a very limited narrow range, a part of Fe is replaced with Mn, more preferably, the composition purity, relative sintering. By limiting the density and the average crystal grain size, an extremely small value of ΔH can be realized, and a high-frequency magnetic material having a higher electric resistance can be provided. In addition, a part of Fe was replaced with Al so that 4 πMs could be set to an arbitrary value while realizing high electric resistance.

The garnet-based high-frequency magnetic material of the present invention has a composition represented by Y _A (Fe _1-BC Al _B Mn _C ) _8-A O _{12 in} which A, B and C are each in the range of 3.01 ≦ A ≦ 3.08, 0 ≤
B ≦ 0.5, 0 ≦ C ≦ 0.009.

Preferably, the composition has a purity of 99-9.
9.99%, a relative sintered density of 95 to 99.9%, and an average crystal grain size of 5 to 50 μm.

That is, the present invention satisfies a predetermined composition purity, a relative sintered density and an average crystal grain size with respect to a magnetic material composed of YIG ferrite, so that ΔH is 7 (Oe) or less.
Preferably, a low-loss garnet-based high-frequency magnetic material having a high resistance of not more than 5 (Oe) and not less than 10 ¹⁰ (Ω · cm) at room temperature is obtained. In addition, 4 πMs can be set arbitrarily in the range of 100 to 1800 Gauss, and
A material having πMs can be selected. Further, the insertion loss of the high-frequency nonreciprocal circuit element is -0.8 (db) or less, preferably -0.5
(db) or less.

In the present invention, the reasons for setting the composition ratio of the components to the above range are as follows. A range 3.01 ≦ A
The reason for ≦ 3.08 is that when A is less than 3.01, the electric resistance value decreases and the dielectric loss decreases. When A exceeds 3.08, ΔH becomes large. The range of B is set to 0 ≦ B ≦ 0.5 because, in this range, it has a high resistance value and 4πMs is 100 to 19
It can be set arbitrarily in the range of 00 Gauss, but if it exceeds 0.5, ΔH becomes large. C range 0 ≤ C ≤ 0.009
The reason is that in this range, ΔH is not deteriorated,
Although it has the effect of preventing the resistance value from decreasing and reducing the dielectric loss,
If it exceeds 0.009, ΔH will deteriorate.

Further, according to the present invention, the composition purity is 99 to 99.99%
The reason for the following is that if the content is less than 99%, the property is deteriorated due to the non-magnetic material. On the other hand, in order to obtain 99.99%, it is very difficult in terms of material purification.

The composition purity in the present invention refers to the content of Y _A (Fe _1-BC Al _B Mn _C ) _8-A O _{12 in} the final sintered body. Element oxide, SiO ₂ , Al ₂ O ₃ , MgO, CaO, K ₂ O, Cr ₂ O ₃ , ZrO ₂ ,
ZnO, Bi ₂ O ₃ , S, In ₂ O ₃ , V ₂ O ₅ , NiO and the like may each be contained in a range of less than 0.05 part by weight.

In the present invention, the relative sintering density is 95-99.9.
The reason for the percentage is that if it is less than 95%, the effective magnetic material occupation ratio becomes low, and the magnetic characteristics such as ΔH deteriorate. On the other hand, if the content exceeds 99.9%, a special sintering method such as a hot press method is required, which leads to a decrease in productivity and an increase in cost. The relative sintering density is the ratio of the density of the actual sintered body to the theoretical density.

In the present invention, the average crystal grain size is 5 to 50 μm.
The reason is that if it is less than 5 μm, the ΔH characteristic deteriorates and the
If the thickness exceeds μm, ΔH becomes worse and the electric resistance decreases.

In the method for producing a garnet-based high-frequency magnetic material of the present invention, the main ingredients are prepared so as to be in the above-mentioned range, pulverized and mixed by a vibration mill or a ball mill, and then calcined. The powder is obtained by pulverizing the powder with a ball mill, adding a binder, granulating the powder, forming the obtained powder into a predetermined shape by press molding, and firing at a temperature in the range of 1400 to 1600 ° C. It is more preferable to anneal (refire) in the range of 1000 to 1250 ° C. when the temperature of firing is lowered.

Further, the present invention is characterized in that a disc or a substrate processed into a predetermined shape is formed by using the above-mentioned garnet-based high-frequency magnetic material to form a non-reciprocal circuit device. Specifically, it can be suitably used for isolators, circulators, gyrators, and the like in high-frequency circuits such as microwaves and millimeter waves.

[0022]

EXAMPLE 1 A main component composed of Y ₂ O ₃ , Fe ₂ O ₃ , Al ₂ O ₃ and MnO having a purity of 99% or more was changed as shown in Table 1, and mixed with a vibration mill or a ball mill. And calcined at 1000 ° C to 1200 ° C. After pulverizing the calcined powder with a ball mill, adding a predetermined binder and granulating, forming into a circular or columnar shape by compression molding, and firing this molded body at 1400 ° C. to 1600 ° C.,
Annealed (refired) at 1000 ° C. to 1200 ° C. when the temperature was lowered to obtain a sintered body. The relative sintered density of the obtained sintered body was 95% or more, and the average crystal grain size was 5 to 50 μm.

With respect to the obtained sintered body, 4 πMs was measured using a vibration magnetometer, and ΔH at 3 GHz was measured in a spherical sample measuring TE _10n resonator. The resistance value is JI
The measurement was performed according to the standard of SC-2141.

Further, a lumped constant type isolator for 1.9 (GHz) was fabricated and measured for insertion loss. Regarding the insertion loss of the present embodiment, as a representative of the high-frequency non-reciprocal circuit element,
The lumped constant type isolator will be described as an example, but the present invention is not limited to this, and the same effect can be obtained in other types of high-frequency nonreciprocal circuit devices.

The results are as shown in Table 1. From these results, in the composition represented by the composition formula Y _A (Fe _1-BC Al _B Mn _C ) _8-A O ₁₂ , in the case where A is less than 3.01 (No. 1 to 3),
ΔH is large and electric resistance is low. On the other hand, in the case where A exceeded 3.08 (Nos. 5 to 7), only ΔH was large. Also, B
ΔH was large even when the ratio exceeded 0.5 (Nos. 3, 4, and 7). Also, ΔH was large even when C exceeded 0.009 (Nos. 14 and 17).

On the other hand, the embodiment of the present invention in which the value of A is 3.01 to 3.08, the value of B is 0 to 0.5, and the value of C is 0 to 0.009
(Nos. 8 to 13, 15, 16), ΔH was as low as 7 (Oe) or less,
The electrical resistance was as high as 10 ¹⁰ (Ω · cm) or more. Also, by setting the value of B to be 0 to 0.5, 4πMs could be set arbitrarily from 100 to 1800 while maintaining the desired ΔH and electric resistance.
It was also found that by setting the value of C to 0 to 0.009, the electric resistance could be further increased while maintaining the desired ΔH.

Next, according to the insertion loss results obtained by incorporating these garnet-based high-frequency magnetic materials into an isolator, in the present invention (Nos. 8 to 13, 15, and 16), the loss is as small as -0.5 (db) or less. I understood. It should be noted that the same result was obtained with other types of high-frequency nonreciprocal circuit devices.

[0028]

[Table 1]

Example 2 Next, the composition was fixed to A _3.05 (Fe _0.745 Al _0.25 Mn _0.005 ) _4.95 O ₁₂ , and the composition purity, relative sintered density and average crystal grain size were determined as shown in Table 2.
And the other conditions were the same as in Example 1 above to obtain a circular or columnar sintered body.

The obtained sintered body was measured for ΔH, 4πMs, electric resistance and insertion loss in the same manner as in Example 1, and the results are as shown in Table 2.

From these results, those having a composition purity of less than 99%
(No.18,19), those with a relative sintering density of less than 95% (No.18, 2)
0), having an average crystal grain size of less than 5 μm (No. 25, 26, 2
8,29), ΔH was 8 (Oe) or more, and both were large. Further, those having an average crystal grain size exceeding 50 μm (No. 31, 3
In (2), ΔH was large and the electric resistance was as low as 10 ⁸ (Ω · cm) or less.

On the other hand, the composition purity is 99 to 99.99%, the relative sintering density is 95 to 99.9%, and the average crystal grain size is 5 to 99.99%.
In the examples (Nos. 21 to 24, 27, and 30) of 50 μm, it was found that the electric resistance was as low as 10 ¹⁰ (Ω · cm) and the ΔH was as low as 7 (Oe) or less.

Next, according to the insertion loss results obtained by incorporating these garnet-based high-frequency magnetic materials into an isolator, in the present invention (Nos. 21 to 24, 27, and 30), the loss was as small as -0.5 (db) or less. I understood. It should be noted that the same result was obtained with other types of high-frequency nonreciprocal circuit devices.

[0034]

[Table 2]

[0035]

As described above, according to the present invention, Y _A (Fe
_1-BC Al _B Mn _C) in the composition represented by _8-A O _{12, A}
, B and C are respectively 3.01 ≦ A ≦ 3.08, 0 ≦ B ≦ 0.5
, 0 ≦ C ≦ 0.009, and the composition purity is 99 to 99.99%
By setting the relative sintering density to 95 to 99.9% and the average crystal grain size to 5 to 50 μm, 4πMs becomes 100 to 1800.
In any range of (G), ΔH can be reduced to 7 (Oe) or less while maintaining electric resistance of 10 ¹⁰ (Ω · cm) or more.

The use of the high-frequency magnetic material makes it possible to increase the frequency and reduce the loss of non-reciprocal circuit devices such as isolators, circulators and gyrators. Therefore, if this non-reciprocal circuit device is used in a high-frequency circuit, it can contribute to the increase in the frequency of various information and communication devices.

Claims (3)

[Claims] In a composition represented by Y _A (Fe _1-BC Al _B Mn _C ) _8-A O ₁₂ , each of A, B and C is 3.01 ≦ A ≦ 3.0
8, a magnetic material for high frequency, wherein 0 ≦ B ≦ 0.5 and 0 ≦ C ≦ 0.009. 2. The high frequency device according to claim 1, wherein the content of the main component is 99 to 99.99%, the relative sintered density is 95 to 99.9%, and the average crystal grain size is 5 to 50 μm. Magnetic material. 3. A high frequency non-reciprocal circuit device using the magnetic material according to claim 1 or 2.