Li_2O-Fe_2O_3一Bi_2O_3系アモルファスフェライトの合成と物性

概要

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Ferromagnetic amorphous oxides were prepared by rapidly quenching the molten antiferomagnetic ferrite BiFeO_3 containing lithium oxide. The composition range giving an amorphous phase in the system of Bi_2O_3-Li_20-Fe2O_3 was found to contain more than 30mol% Bi_2O_3. Composition within this range gave X-ray amorphous phase on quenching were confirmed to be an amorphous by X-ray diffraction analysis. Especially, the crystallization emperature of the composition 20 Li_2O・30 Bi_2O_3・50 Fe_2 O_3 was observed 430°, 580° and 730℃ by differential thermal analysis. The saturation magnetization and coercive force of this amorphous oxide were about 13 emu/g at 15 k Oe and about 100 Oe at room temperature, respectively. The thermomagnetic curve showed irreversible change and the curve was slanted near the Curie point. Extrapolation gave the Curie temperature at 563 ℃. <57>^Fe Mossbauer absorption spectra indicated that the amorphous phase is composed of two phases paramagnetic and ferromagnetic having small particles. X-ray photo spectroscopy spectra showed that Fe^<3+> ions exist in both states of 6-coordinate site and 4-coordinate plus 6-coordinate sites.
社団法人日本セラミックス協会の論文
1990-05-01