THE EFFECT OF DIAMAGNETIC DEFECT IN YIG ON THE HYPERFINE FIELD ANISOTROPY

The dependence of Fe-57 NMR spectra in YIG on the external magnetic fi eld direction was measured at 4.2K. The high purity single crystal of a spherical form was used. The external magnetic field of 0.75T was ap plied in several directions lying in (110) plane. The satellite struct ure of the spectra caused by an antisite defects Y(a) (Y3+ ion on the a site, nominally occupied by Fe3+ ion) enabled us to study the effect of a nonmagnetic impurity on the Fe-57 hyperfine field anisotropy. Th e tensors of hyperfine interaction for Fe-57 in d-sites with the neare st and next nearest Y(a) defect were obtained from NMR data. The resul ts were confronted with the predictions of the independent bond model.