Relationship between Crystal Structure and Magnetostrictive Properties of Cu<sub>0.8</sub>Co<sub>0.2</sub>Fe<sub>2</sub>O<sub>4</sub>

The relationship between crystal structure and magnetostrictive properties of Cu0.8Co0.2Fe2O4 was investigated. Although the as-synthesized Cu0.8Co0.2Fe2O4 sample showed a tetragonal spinel structure, a cubic spinel structure was obtained by heating at 1033 K and subsequent quenching. The as-synthesized sample was strained moderately by the application of magnetic fields. The magnetic field dependence of strain magnitude showed moderate changes without a saturation below 2.4 T. On the other hand, the sample quenched from 1033 K strained more sensitively by the application of magnetic fields in comparison with the as-synthesized sample and the magnitude of strain showed a maximum at approximately 0.2 T. Therefore, magnetostrictive properties of Cu0.8Co0.2Fe2O4 are strongly related to its crystal structure.