Study of the Sublattices Magnetisations in Mn0.6Zn0.4Fe₂O₄ by Neutron Diffractometry and Mössbauer Spectrometry

The temperature dependence of the two sublattices magnetisations of Mn 0.6 Zn 0.4 Fe 2 O 4 was determined in order to study the superexchange interactions in Mn 2+ –O 2+ –Fe 3+ linkages. The tetrahedral and octahedral sublattices magnetisations were obtained in absolute scale by neutron diffractometry. Moreover by Mössbauer spectrometry the octahedral sublattice magnetisation was determined in a relative scale as a function of temperature. The results obtained by both methods show the same temperature dependences within the experimental accuracy. The Mössbauer spectra recorded at temperatures higher than 100°K show line broadening and overlapping indicating relaxation effects. The molecular field parameters were deduced from the experimental results on the basis of the Néel model. The best agreement is found for J AA = 0, J AB = (−19 ± 1)°K, and J BB = (4.7 ± 2)°K. The failing B moment and the evidence for a positive B–B interaction are discussed.