Mössbauer and magnetic study of Mn²⁺- and Cr ³⁺-substituted spinel magnesioferrites of the composition Mg _1-xMn_xFe_2-2xCr_2xO₄

Chromium and manganese co-substituted spinel magnesioferrites of the composition Mg_1-xMn_xFe_2-2xCr_2xO ₄ (x=0.0, 0.1, 0.2, 0.3, and 0.5) were investigated with X-ray diffraction (XRD), Mössbauer spectroscopy and magnetic measurements. The cation distribution inferred suggests that Mn²⁺ and Cr³⁺ ions dominantly occupy the A- and B-sites respectively. The gradual decrease of the hyperfine fields and Curie temperatures with increasing x reflects a gradual weakening in the AB exchange interaction. Mössbauer data of the sample with x = 0.5 is suggestive of cation clustering and/or superparamagnetism. The magnetization data is suggestive of Yafet-Kittel-type canted magnetism.