MAGNETIC DOMAIN BEHAVIOR OF CU-CO SPINEL FERRITE SYSTEM

Ferrimagnetic oxides may contain single domain or multidomain particles and they convert into superparamagnetic state near the Curie temperture. To explore the existance of these particles Cu-Co mixed spinel ferrites were prepared by standard ceramic technique. The structural aspects of samples were characterised by X-Ray Diffraction and magnetic measurement. All the studied compounds were crystalline and single phase. The hysteresis parameters were found by vibrating sample magnetometer. The low field a.c. susceptibility measurements were carried out from 300K to Curie temperature, and the normalized susceptibility was plotted as a function of temperature. The variation in susceptibility was attributed to the transition from single or multidomain to superparamagnetic particle state. The observed results are explained on the basis of magnetic particles, grain size and magnetic anisotropy of the system.