Non-collinear spin arrangements in NiZn ferrites studied by the Mössbauer effect

Samples of the nickel-zinc ferrite series Ni_xZn_1-xFe₂O₄ with x = 0.15, 0.20, and 0.25 have been studied by the Mössbauer-effect technique at liquid helium temperature using longitudinal magnetic fields of 16kOe. The hyperfine fields at ⁵⁷Fe nuclei in A and B sites have been determined. Canted spin structures associated with Fe³⁺ ions are observed for all samples. Spectra were fitted using a localized canting model. The ratio of intrasublattice to intersublattice exchange constants resulting in the best fit is J_BB/J_AB = 0.130±0.005.