Abstract
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 Ga
3+ ions replaces the Fe
3+ ions in MnFe
2−
x
Ga
x
O
4. 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.