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 Neel temperature, thereby can be applied to magnetic device. The site preference of Fe2+ and Fe3+ in mixed ferrite ZnxGe1-xFe2O4 (X = 0.6) with Mossbauer 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 Mossbauer measurements. Zn2+ and Ge4+ randomly occupy A site or B site. Mossbauer spectra of Zn0.6Ge0.4Fe2O4 reveal line broadening with increasing temperature and the relaxation effect at low temperature.