JPH0775206B2 - Microwave / millimeter wave magnetic composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a magnetic material composition used in a high frequency region such as a microwave and a millimeter wave.

<Prior Art> Conventionally, Mn-Mg ferrite, Ni-Zn ferrite, YIG ferrite, lithium ferrite and the like have been used as high frequency magnetic material.

These are excellent materials with saturation magnetization (4πMs) values of 500-4000 Gauss.

Among them, especially lithium ferrite has 4πMs of 3700
Since it is as large as Gaussian and has a high Curie point (Tc) near 650 ° C, the temperature change rate near room temperature of 4πMs is small, so it is a material that can be applied to circuit elements such as highly stable isolators and circulators. is there.

<Problems to be Solved by the Invention> However, lithium ferrite has a drawback that losses such as ferromagnetic resonance absorption half-value width (ΔH) and dielectric loss (tan δe) are larger than those of other ferrites for microwaves and millimeter waves. have.

For example, pure lithium ferrite Li _0.5 Fe _2.5 O ₄ has ΔH
And tan δe at a frequency of 10 GHz are as large as 500 Oersted or more and 0.01 or more, respectively, and often cannot be used for actual microwave / millimeter wave circuit elements.

The present invention has been made in view of the above problems, and a part of Li _0.5 Fe _2.5 O ₄ is replaced with Zn to increase 4πMs so that it can be used in a high frequency band, and the amount of Zn 4πMs can be set to an arbitrary value by appropriately changing the value, and PbO is added to contain ΔH and tan.
It is an object of the present invention to provide a microwave / millimeter wave magnetic material material having an improved δe.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the magnetic substance composition for microwave / millimeter wave of the present invention is Li _x Fe _y Zn _z O _{0.5 + y + 0.5z} (where _{x + y + z = 1} ), x, y,
z is 0.10 ≦ x ≦ 0.21, 0.77 ≦ y ≦ 0.88, 0.02 ≦
It is characterized in that the main component is a composition in the range of z ≦ 0.13, and 0.01 mol% or more and 0.5 mol% or less of lead oxide represented by the form of PbO is added thereto.

<Operation> According to the present invention, 4πMs can be arbitrarily set within the range of 3900 to 5100 gauss, and therefore, a material having a value of 4πMs most suitable for the frequency used can be selected.

According to the present invention, a material having a higher value of 4πMs than other ferrites for microwave and millimeter waves can be obtained.
It is suitable for use in 30GH _z or ultra high frequency band.

Further, according to the present invention, since Tc is high, the temperature change rate of 4πMs near room temperature is small, and further, ΔH and tan δ
It is possible to obtain a magnetic material having a sufficiently small e and good microwave / millimeter wave characteristics.

Regarding the above-mentioned objects, features, and advantages of the present invention,
Examples will be described below with reference to the drawings.

Example First, as raw materials, high-purity Li ₂ CO ₃ , Fe ₂ O ₃ , ZnO, and
Prepared PbO. These raw materials were weighed so that the composition shown in Table 1 was obtained, and wet mixed with a ball mill for 16 hours using ethyl alcohol as a dispersion medium. After this mixture was dried, it was calcined at 850 ° C. for 2 hours to obtain a calcined product. This calcined product was put into a ball mill together with ethyl alcohol and an organic binder, and wet-milled for 16 hours. The pulverized product was dried and then granulated through a 50-mesh net, and the obtained powder was molded into a 3 mm × 3 mm × 20 mm prism at a pressure of 2000 kg / cm ² . After this molded product was fired at 1050-1200 ℃ for 2 hours, it was machined to form a sphere with a diameter of 1.3 mm and a diameter of 1.3 mm and a length of 16 mm
A cylindrical sample of was obtained.

For the obtained spherical sample, 4πMs and Tc were measured using a vibrating magnetometer, and ΔH at 10 GHz was measured in a TE106 cavity resonator.

Further, ε and tan δe at 10 GHz were measured for the cylindrical sample in the TM010 cavity resonator by using the displacement method. The results are shown in Table 1.

Incidentally, the * mark in Table 1 is out of the scope of the present invention, and all other items are within the scope of the present invention.

Furthermore, the results of the experimental examples shown in Table 1 are shown as Li _x Fe _y Zn _z O
_It is shown in the three-component composition diagram showing the composition ratio of _{0.5 + y + 0.5z} . The numbers in this figure represent the sample numbers. In this drawing, a region showing a composition ratio within the scope of the invention is shown by a triangle having vertices A, B and C.

Next, the reason why the composition range of the present invention is limited will be described.

Samples Nos. 1, 6, 11, 16, 21 and 26, in which the amount of PbO added is 0.01 mol% or less, have ΔH and tan δe.
Is not suitable for practical use.

In addition, as in sample numbers 5, 10, 15, 20, 25 and 30, Pb
If the amount of O added exceeds 0.5 mol%, tan δe becomes large, which is not preferable.

For samples with z of 0.02 or less, such as sample numbers 31 and 32,
This is excluded from the scope of the present invention because it has no effect of improving 4πMs by Zn.

If x is 0.10 or less, like sample numbers 33 and 34,
ΔH is large and Tc is low, so that the temperature change rate of 4πMs is large, which is not preferable.

If y is 0.77 or less like sample numbers 35 and 36, Δ
H and tan δe increase, which is not preferable.

On the other hand, the magnetic composition of the present invention has sufficiently small ΔH and tan δe, and has a high Tc.
Further, the magnetic material composition of the present invention has a larger value of 4πMs than other magnetic materials for microwaves and millimeter waves, and thus can be used in a frequency band higher than those magnetic materials.

Further, by appropriately changing x, y and z represented by the chemical formula of Li _x Fe _y Zn _z O _{0.5 + y + 0.5z} within the scope of the present invention, the value of 4πMs can be freely selected from 3900 to 5100 gauss. Therefore, it is possible to obtain the value of 4πMs most suitable for the frequency used.

[Brief description of drawings]

The drawing is a three-component composition diagram showing the composition ratio of Li _x Fe _y Zn _z O _{0.5 + y + 0.5z in} the microwave / millimeter wave magnetic material composition according to the present invention.

Claims (1)

[Claims] 1. Li _x Fe _y Zn _z O _{0.5 + y + 0.5z} (where _{x + y + z =
In the} composition represented by ₁ ), x, y and z are respectively
0.10 ≤ x ≤ 0.21, 0.77 ≤ y ≤ 0.88, 0.02 ≤ z ≤ 0.13 is the main component, and lead oxide expressed in the form of PbO is added by 0.01 mol% or more and 0.5 mol% or less. A magnetic substance composition for microwaves and millimeter waves.