Magnetic and structural properties of Cu_1-xCo_xFe₂O₄ nanoparticles prepared by a modified solgel method

A series of Cobalt substituted copper ferrite (Cu_1-xCo_xFe₂O₄) nanoparticles (x=0.0.1,0.2,0.4,0.6,0.8 and 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 group I41/amd) to cubic (space group Fd3m) phase is exhibited with the substitution of Cu²⁺ by Co²⁺. The crystallite size of samples varies from 18-32nm 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 300K and 5K over a field range of ±100kOe. 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 300K and 5K The variation of coercivity and magnetocrystalline anisotropy have been studied and the correlation between these parameters are investigated.