JPS6026069B2 - Lithium-germanium ferrite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a saturation magnetization (4 NB) of 400 Gauss to 4 Gauss.
The present invention relates to a lithium-germanium ferrite used in microwave circuit elements in the range of 300 Gauss.

The characteristics required of a microwave circuit element are that it has 4mMs necessary to avoid low magnetic field loss, has small magnetic loss and dielectric loss, has a high Curie temperature Tc, and has a small temperature change of 4mMs. Currently used materials for microwave circuit elements include Y-Fe garnet, Mn
-Mg-based ferrite, Ni-based ferrite, etc.

Y-Fe-based garnet has a Curie temperature of 280° C. or less, and as a broadband microwave circuit element above HZ of frequency band 1, it may have the drawback that it has a large temperature change of 4 mms and is not highly stable. Furthermore, Mn--Mg ferrite and Ni-based ferrite have drawbacks such as a large dielectric loss or a small magnetic loss, resulting in a low Curie temperature and a large temperature change of 4 mMs.
The present invention aims to improve these drawbacks by using Lio. fe2
．． 5 was partially replaced with W and Cr. 5xFe
2.5-,. The present invention provides an Lj-W ferrite represented by the chemical composition formula: Li-based ferrite generally has a high Curie temperature (Lio.5F
Tc at e2.504 and 660°C) 4 Ms at around room temperature
Although it has an excellent feature of small temperature change, it has drawbacks such as lack of oxygen and easy evaporation of Li during firing, and increased dielectric loss due to the production of Fe20 ions.
However, Li〇. In the case of Cr, in the composition formula of zue2.5-lengthJ3y04, a product with length n6d 1×10-3 can be obtained with a substitution range of 0.01 mm and 0.6 mm. However, C
If only r is used, Δday is very large, making it difficult to put it into practical use. However, by simultaneous substitution with Ge, it is possible to reduce Δday while keeping tan61 small. The following will be explained based on examples. Li Small 5xFe2.5-
、． 5-x- Based on the chemical composition formula of eXCry04, weighed the raw materials of Li2C03, Fe203, and Cr203, mixed them with alcohol as a dispersion medium in a steel ball mill, pre-calcined them for 75 minutes, pulverized them, and mixed them with a binder. 10
Firing was carried out in oxygen at 00 to 1200 qo. The specific measurement was carried out using a magnetic balance with a Curie temperature of 4mMs and a disk-shaped sample with a thickness of 0.2-0.3 mm and a thickness of 12-14 mm.9. and HZ TE,. It was determined by the perturbation method using a two-cavity resonator. △Day is 9. Measured by reaction method at $HZ. Reference example Li ship Fe2.5-yCry04 composition with Cr substitution 1
Table 1 shows the properties when the samples were annealed at 200° C. in 100°C oxygen and then annealed at 200°C.

As shown in Table 1, a high Curie temperature can be obtained at a low temperature of 4mMs, and a very small temperature change of 4mMs can be obtained near room temperature.

However, when y<0.05, tan6' becomes as large as 8×10-3, and the effective range of the present invention is 0.05 mm and y×0.6. However, with only Cr substitution, there is a mirror direction in which Δday becomes large, which is not practical. An example in which snakes are simultaneously replaced for the purpose of improving these is shown below. Example Lio. 5
Ten o. Scales Fe2.5-,. 5x-X history. Table 2 shows the characteristics when Cr and W were simultaneously substituted in the composition of Cry04, fired at 1200° C. in yuzu oxygen, and then annealed for 850 minutes and 1 hour.

Tables 2 and above As shown in Table 2, it can be seen that due to Q substitution, the number of △ days tends to decrease, and it is improved during the middle of the day.

At x=0.2, the number of Δ days is less than half that of x=0, and the effectiveness of Q substitution is clear. Besides, tan6 rice is 10-4
Of order and small value. It can thus be seen that the composition of the present invention functions as a microwave/millimeter wave ferrite having a high Curie temperature and a small temperature change of 4mMs.
However, if x>0.9, the Curie temperature will be the same as that of pond-based ferrite, which has long-lasting properties, and the effectiveness will be lost.

When the Curie temperature is high, the saturation magnetic flux density (4mMs
) The temperature change is small around room temperature. Therefore, in order to obtain characteristics with a small temperature change of 4mMs, it is necessary to increase the Curie temperature. Spinel crystal Ni-Zn ferrite used as microwave ferrite, Mn-
The Mg-based ferrite used is 4mMs (1500~5
In the range of 0.000 Gauss), the temperature of the four ships was 0.18%/℃ or more, even for small sharks.

The ferrite of the present invention has a high Curie temperature and a relatively high Curie temperature within the range of 4 mNs used, and a small temperature change of 4 mms. For example, in Table 2, x:0.05 y=
The temperature change of 4-layer Ms with a composition of 0.5 is 0.060%/℃
, x=0.1, y=0.1 shows a value of 0.0 spot %/00. Furthermore, when x<0.02, the substitution effect is not significant.

Claims (1)

[Claims] 1 Li_0_・_5_+_0_・_5xFe_2_・
A chemical composition formula represented by _5_-_1_・_5x-yGe_xCr_yO_4, 0.02≦x≦0.9, 0.
A lithium-germanium ferrite characterized by having a composition in the range of 01≦y≦0.6.