Structural analysis and magnetic properties of biphasic chromium-substituted copper ferrites

Abstract

Nano CuFe2−xCrxO4 ferrite has been prepared by citrate autocombustion method. The impact of heat treatment and Cr contents on the structural phases and parameters were studied by tracing X-ray diffraction (XRD) patterns. As-prepared samples were found to contain a major cubic CuFe2O4 phase associated with minorities of CuO and tetragonal CuFe2O4 phases. Upon annealing at 600 °C, the content of tetragonal phase increased while CuO phase disappeared. On the other hand, replacing Fe by Cr in the CuFe2−xCrxO4 system reduces the formation of the tetragonal phase. Carrying out Rietveld analysis, the phase percentage and lattice parameters of both phases as well as the crystallite size were correlated with Cr content. Moreover, the change of the inversion occupancy parameter and the degree of tetragonality were studied in detail. Finally, magnetic properties including saturation magnetization and coercive field of the annealed samples, and their dependence on the degree of tetragonality and crystallite size, were elaborated using vibrating sample magnetometry (VSM).