High-field Mössbauer study of manganese-zinc ferrites

The disordered ferrite system, Mn_1-xZnₓFe₂O₄ for 0≤x≤0.95 has been studied by the M\"ossbauer-effect technique at 4.2 K in applied magnetic fields of 50 and 90 kOe. In these fields a ferrimagnetic structure is implied for the entire family of compounds. For $x=0$ the cation distribution is (Mn0.82{Fe}0.18$)[${Mn}0.18Fe1.82]O₄; for larger x the iron concentration on A (tetrahedral) sites decreases, and becomes less than 2 at.% by $x=0.6$. For x≥0.6, some of the Fe ions on B (octahedral) sites have their spin moments reversed. Within the experimental error, the magnetic moments of the iron ions are collinear for $x<0.5$ and noncollinear for $x>0.5$. The canting angles for normal B-site cations are found to increase with increasing zinc content, and to depend on the applied field. The sample with $x=0.80$ has the most stable structure. The hyperfine fields and isomer shifts show only a small variation with sample composition.