On the enhanced coercive field and anisotropy observed in cobalt substituted copper ferrite nanoparticles prepared by a modified sol-gel method

A series of cobalt substituted Copper ferrite (Cu_1−xCo_xFe₂O₄₎ nanoparticles (x = 0,0.1,0.2,0.4,0.6,0.8and 1) are prepared by a modified sol-gel auto combustion method. The structural analysis carried out by the X-ray powder diffraction technique shows a structural transition from tetragonal(space groupI41/amd) to cubic(space groupFd3m) phase is exhibited with the substitution of Cu²⁺ by Co²⁺. The crystallite size of samples varies from 18 to 32 nm while an increase in the lattice parameter is observed with cobalt substitution. Magnetic hysteresis loop measurements have been performed using Vibrating Sample Magnetometer (VSM) at 300 K and 5 K over a field range of±100 kOe. Saturation magnetization shows an increasing pattern with cobalt concentration and attains a maximum value 76.13 emu/g and 82.528 emu/g for x = 0.8 sample at 300 K and 5 K The variation of coercivity and magnetocrystalline anisotropy have been studied and the correlation between these parameters are investigated.