Effect of Heat Treatment on Magnetic Properties of Ferrimagnetic Zinc Ferrite Prepared by Rapidly Quenching Method
- Resource Type
- Journal Article
- Authors
- K. HIRAO; K. TANAKA; M. MAKITA; N. SOGA
- Source
- Journal of the Magnetics Society of Japan. 1998, 22(S_1_ISFA_97)77
- Subject
- Language
- English
- ISSN
- 0285-0192
1880-4004
We have examined the effect of heat treatment temperature and time on magnetic properties of rapidly quenched oxides with compositions close to ZnFe2O4. These oxides show high magnetization even at room temperature as we reported previously. In particular, attention is focused on oxide with nominal composition of 60ZnO•40Fe2O3. It is suggested that the high magnetization is brought about by iron ion clusters with Zn2+ ions occupying octahedral sites as well as solid solution of Fe3O4 in ZnFe2O4. As the heat treatment temperature increases, the room temperature magnetization decreases sluggishly below 500°C and decreases sharply above 600°C when the heat treatment time is 2 h. It is proposed that the decrease of magnetization below 500°C corresponds to disappearance of iron ion clusters while the rapid decrease of magnetization above 600°C is caused by oxidation of Fe2+ to form ZnFe2O4 with normal spinel structure.