Correlating structural, magnetic, and luminescence properties with the cation distribution of Co0.5Zn0.5+xFe2–xO4 nanoferrite

Abstract

Structural, magnetic, and luminescence properties have been investigated for Co0.5Zn0.5+xFe2−xO4 nanoferrite (0.0≤x≤0.4, with a step increment of 0.1) prepared by citrate autocombustion method. X-ray diffraction (XRD) patterns and Fourier-transform infrared (FTIR) spectra proved the formation of a pure cubic spinel phase for all AP samples. Although the ionic radius of Zn2+ is larger than that of either Fe3+ or Co2+, Rietveld analysis showed that the lattice parameter mostly decreases with increasing Zn substitution. The crystallite size of AP samples decreases gradually with increasing Zn substitution from 16 to 10nm, which is confirmed with high-resolution (HRTEM) micrographs. Magnetic parameters such as saturation magnetization, coercivity, and remanent field obtained from vibrating sample magnetometry (VSM) revealed a strong dependence on the cation distribution being proposed according to the experimental data of XRD, FTIR, and VSM. The cation distribution indicated that introduced nonstoichiometry is compensated by oxidizing Co2+ into Co3+, which explains the trend of the lattice parameter with increasing x. The distribution of Fe3+ ions between octahedral and tetrahedral sites was further confirmed by photoluminescence (PL) emission spectra.