Synthesis and structural studies on Ni0.5+x Zn0.5Cu x Fe2?2x O4

The mixed ferrites of Ni–Zn–Cu are synthesized using ceramic double sintering technique. Cu and Ni are substituted in steps of x=0.1 at the interstitial sites of Fe. Powders of mixed ferrites of Ni–Zn–Cu are studied using XRD. The mixed ferrites show a single phase and face center cubic structure for all concentrations. The substitution of Cu and Ni are confirmed from the variation of lattice constant. The cation distribution in the A and B sites of the ferrites is estimated. Mixed ferrites of Ni–Zn–Cu are characterized using a.c. conductivity and magnetic susceptibility methods. The variation of activation energy, magnetic moment and Curie temperature with concentration of Fe ions explains the alterations of the energy levels of d bands. Hopping of charge carriers and the presence of different ionic states of Ni, Cu, and Fe ions are discussed using the FTIR and EPR spectra.