Site preference for Zn2+ and Ge4+ in mixed ferrite ZnxGe1−xFe2O4

Small amounts of Zn2+ and Ge4+ substituting for GeFe2O4 and ZnFe2O4, can efficiently increase the Neél temperature, thereby can be applied to magnetic device. The site preference of Fe2+ and Fe3+ in mixed ferrite ZnxGe1−xFe2O4 (X=0.6) with Mössbauer absorption and x-ray diffraction was studied. Analysis of x-ray diffraction indicates that the lattice constant is not in accord with Vegard’s law, suggesting Fe2+ and Fe3+ are located not only at B sites but at A sites. It is found that Debye temperatures of GeFe2O4 and ZnFe2O4 are 380±5 K and 361±5 K from Mössbauer measurements. Zn2+ and Ge4+ randomly occupy A site or B site. Mössbauer spectra of Zn0.6Ge0.4Fe2O4 reveal line broadening with increasing temperature and the relaxation effect at low temperature.