Preparation and characterization of tin-doped spinel ferrite

The chemical preparation of a tin-doped spinel ferrite via the co-precipitation method rendered a sample containing 48.2 mass% Fe3+, 11.8 mass% Fe2+ and 13.0 mass% Sn. Powder X-ray diffractometry data collected with synchrotron radiation source revealed the co-existence of two crystallographic phases: one with cubic (spatial group, Fd3m) spinel and other with trigonal-hexagonal (R3¯c) structure. 57Fe Mössbauer spectroscopy analysis confirmed the occurrence of two tin-doped phases, with relative spectral areas of 50.6% and 49.4%; deduced chemical structures of these two phases correspond to (Fe3+,Fe2+)2.44Sn0.434+⊕0.13O4 and α-Fe1.883+Sn0.124+O3, (⊕, cation vacancy), respectively. The measured value for saturation magnetization σ = 30 J T−1 kg−1 for this sample leads to a Sn4+-ferrite with σ = 60 J T−1 kg−1. The magnetic hyperfine field detected with 119Sn Mössbauer spectroscopy was interpreted as being due to a supertransferred magnetic moment from iron cations to Sn4+ in octahedral sites of these iron oxides lattices.