JPS6220304A - Ferrimagnetic garnet of ce-ca system - Google Patents

Abstract

PURPOSE:To enable inexpensive sintering at low temperature of the same degree or below as usual, by partially substituting cerium and calcium for yttrium of YIG. CONSTITUTION:General ferrimagnetic ceramics is formed with such a composition as shown in the formula. When it is formed, an oxide of each composition element, or the powder of a material, such as a carbonate, oxalate or hydroxide compound, which can be an oxide easily by pyrolysis, is weighed, then crushed and mixed in wet by a tumbling ball mill, and kept at a temperature of 1,125-1,225 deg.C for 3hr. The material thus prepared is cooled down rapidly and calcined temporarily. After the temporary calcination, it is subjected to wet ball-mill fine crushing again by the tumbling ball mill and dried. Thereafter a 3% polyvinyl alcohol water solution of 10wt%, which is an integrating agent, is added to the powder, mixed uniformly therewith, and then the mixture thus obtained is subjected to pressure molding by a mold and calcined for 8hr at a temperature of 1,280 deg.C-1,440 deg.C. Thus, ferrimagnetic garnet of a Ce-Ca system ferrimagnet is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a Ca
-Ca-based ferrimagnetic garnet.

[Conventional technology]

The main characteristics required for ferrimagnetic materials used in microwave communication circuit elements are low magnetic and dielectric loss and small temperature changes in saturation magnetization value, in other words, high temperature. It is. Furthermore, from an industrial standpoint, it is desirable that it can be supplied at low cost. The ferrimagnetic material currently used in microwave circuit elements is yttrium-iron garnet called YiG (represented by the compositional formula Y s F 9 s 012).

), and its greatest feature is that both the ferromagnetic resonance absorption half-maximum value (ΔH), which indicates magnetic loss, and the dielectric loss (−δρ), which indicates dielectric loss, are small.

However, the raw material of YIG, yttrium oxide, is expensive, and it is difficult to obtain the desired excellent properties.

9. It is necessary to sinter at a high temperature. There was an industrial problem.

Therefore, as shown in Journal of Applied Physics, Vol. 3, 1969, pp. 929-937, 1) Yttrium is synthesized as shown in the composition formula YCexF85012.
There is a garnet that is converted to 1 by x ram alone, but in this case,
The solid solubility limit of cerium to form a single garnet group is approximately! △H of magnetic loss narrowly in the range of <0.15~01B
In addition, the sintering temperature increases with X, and the sintering temperature is also high, which is the same as that of YIG. Furthermore, replacing yttrium with calcium alone has the problem that, even if only for a small amount, the valence balance of ions in the garnet becomes unbalanced, resulting in poor magnetic properties.

This invention was made to solve these problems, and without impairing the excellent properties of YIG2, for example, a cheaper raw material can be used as a part of the expensive yttrium oxide. The purpose of the present invention is to obtain an inexpensive Co-Ca-based ferrimagnetic garnet using easily available materials that can be sintered at a lower temperature than the average temperature.

[Means for solving problems]

The Ce-'Ca-based ferrimagnetic garnet of this invention is.

General formula % Formula % where o(x(0,54, o<y<054 ax-o,
1s<y<x).

[For production]

The fact that yttrium in YIG in this invention is partially replaced with cerium and calcium makes it possible to use compounds such as cesium oxide and calcium hydroxide, which are cheaper than yttrium oxide, as raw materials, making it cheaper and moreover, It is possible to sinter at a lower temperature than that of .

〔Example〕

The polycrystalline sample was obtained through a common manufacturing process for ferrimagnetic ceramics. That is, the composition formula is YCe
Raw material powders that can easily become oxides by thermal decomposition such as oxides, carbonates, oxalates, and hydroxide compounds of each -x-y constituent element are weighed and wet-pulverized and mixed in a 9-turn ball mill so that xCayFe5012 is obtained. 1125
The mausoleum was kept at ~1225℃ for 3 hours.

It was rapidly cooled and pre-fired. After pre-calcination, wet ball mill pulverization is performed again using a rotary ball mill. After drying, add 10 tbsp of 3-tivolivinyl alcohol aqueous solution as a binder to the dried powder, mix uniformly with the powder, and then press-mold with a mold.
After firing at 1280°C to 1440°C for 8 hours, the Ce-Ca-based ferrimagnetic garnet of the example of this invention was obtained by furnace cooling, and the Curie temperature (TC) and the saturation magnetization value at room temperature (
4πMs) and ΔH2−δ at a measurement frequency of 10 GHz.
We measured ε. The results are shown in the table.

In the table, the sample name, Am, 2 to 1 polycrystalline YI (), as seen in flat 1 (, fired at 1440°C, i, 7
'Ht, @stand, ΔTT -450e, tAllδ
<2×1c1. Although it shows excellent characteristics,
When the firing temperature is lowered to 1400°C as shown in Figure 2,
Sintering becomes insufficient, resulting in an increase in ΔH. Furthermore, as seen in 1.3 and 4.5, in the C8-China-German substitution, when Ce company X exceeds o and val, ΔH increases rapidly.

On the other hand, trial A of the embodiments of this invention marked with 7
6, 7, 8, and 9 have excellent characteristics comparable to or superior to YIG in both Curie point and ΔH2-δ, although there is a slight decrease in the saturation magnetization value even when the Co frog I exceeds 1) and 18. Although it has.

When the value exceeds 054, the characteristics deteriorate as seen in A10. Also, Ce and Ca are 8゜12.13,
As seen on 14.15.

■-〇, 18kuY＜,,! -δ1 beyond the range of
or ΔH increases rapidly. From the above.

0<x(:0.54, 0(y(O,54,x-0,1
There must be a range of 8<J<X.

[Effects of the Invention] As explained above in Invention V1, the general formula % (where 0<χ<:o, 54, o<y<054°x-ols<y<x) is used. As a result, it is possible to obtain an inexpensive Ce--Ca based ferrimagnetic 1''t gal-net which can be sintered at a lower temperature comparable to that of conventional products without impairing the excellent properties of YIG.

Claims (1)

[Claims] General formula Y_3_-_x_-_yCe_xCa_yFe_5O_
1_2 (however, 0<x≦0.54, 0<y≦0.54,
A Ce-Ca-based ferrimagnetic garnet represented by x-0.18≦y<x.