Low temperature Mössbauer study of gallium substitution for iron in manganese-ferrite

The effect of gallium substitution on the magnetic hyperfine field of manganese-ferrite at 20 K has been studied by Mössbauer spectroscopy. It was found that the value of the magnetic hyperfine field decreases when a small concentration x of Ga3+ ions replaces the Fe3+ ions in MnFe2−xGaxO4. An increase in the magnetic hyperfine field was observed when the amount x of gallium increased (x ≥ 0.4). No spin canting was observed and all the samples had a collinear structure. The variation of the magnetic hyperfine field with gallium concentration is explained qualitatively on the basis of supertransferred hyperfine interaction.