Low temperature Mössbauer spectroscopic studies on Sm³⁺ doped Zn-Mn ferrites

For the first time, we report on the low temperature Mössbauer spectroscopic study of Zn²⁺_0.5Mn²⁺_0.5Sm³⁺_xFe³⁺_2−xO₄ (where x = 0.01–0.05) prepared by the modified solution combustion method using a mixture of urea and glucose as a fuel. The Mössbauer spectroscopy at room and low temperatures was applied to understand the magnetic properties of the samples. The room temperature Mössbauer spectroscopy results suggest that the occupation of the octahedral sites by Sm³⁺ ions leads to the distortion enhancement of ⁵⁷Fe nuclei environments, which leads to an increase in quadrupole splitting Δ values of D2 and D3 doublets. The low temperature Mössbauer spectroscopy results indicate that the presence of Sm³⁺ ions in the octahedron sites causes the decrease in the number of Fe–O–Fe chains. The transformation of Mössbauer spectra doublets into Zeeman sextets is accompanied by a significant decrease in the magnitude I_M of Mössbauer spectra intensity within the 0–1.2 mm/s velocity range normalized to its value at 300 K. This drop in the temperature dependence of I_M allows one to obtain the magnetic phase transition temperature T_M from the Mössbauer experiment.