Magnetic properties and local structure studies of Zn doped ferrites

A series of nano-particle zinc-doped ferrites samples ZnxFe3 − xO4 (x = 0, 0.17, 0.33, 0.50, and 0.67) were prepared with the hydrothermal method, and the effects of Zn doping on the magnetic properties and local structures of the samples were studied. By increasing zinc content from 0 to 0.33, the saturated magnetization Ms measured with the vibrating sample magnetometry (VSM) method increases, while it decreases by further Zn doping. The experimental results of extended X-ray absorption fine structure (EXAFS) show that most of dopant Zn atoms occupy A site, and only a few Fe atoms at B site are substituted by Zn atoms. The Neel's two-sublattice model and the molecular field analysis of Yafet-Kittel (Y-K) spin-ordering using the three-sublattice model are compared to explain the experimental phenomena. The Y-K angle between the magnetic moments at A and B sublattices is found changing due to the decrease of A-O-B exchange interaction, which shows that the magnetic moments at B site are no longer rigidly parallel to the few remained magnetic moments at A site.