Effect of thermally-induced cationic redistribution on the structural and magnetic properties of Cu-substituted zinc ferrite.

Cationic redistribution in spinel ferrite systems greatly influences the magnetic ordering and the associated phenomena. Here, the effect of the synthesis condition on the cationic redistribution and its correlation with the magnetic properties were explored in the Cu²⁺substituted ZnFe₂O₄spinel ferrite. X-ray photoelectron spectroscopy and x-ray diffraction studies reveal that the variation of sintering temperature redistributes the cations between tetrahedral and octahedral sublattices. Results from low field dc-magnetic susceptibility measurements show that the susceptibility increases with decreasing sintering temperature of the sample. Furthermore, the ac-susceptibility results suggest that the sample sintered at 1048 K (1148 K) exhibits spin-glass behavior with a glass transition temperature of ∼49.2 K (47.1 K) and a cluster-glass behavior at a higher temperature of ∼317 K (330 K), characteristics that are absent in the sample sintered at 1248 K. The sample annealed at 1048 K exhibits a magnetocaloric effect with a maximum isothermal entropy change of ∼1.21 J kg^-1K^-1atμ0H=5T.