Supertransferred Hyperfine Fields and Covalency at Diamagnetic Cations in Magnetic Insulators

Abstract
The sign and magnitude of the antimony hyperfine field has been measured in Sb-substituted nickel ferrite using the Sb121 Mössbauer effect. We obtain a value of -311 ± 4 kG for this field at 100 K. This result is compared with results obtained for Sn in yttrium iron garnet and, among the possible mechanisms, 3d5s covalent spin transfer appears to make the predominant contribution to the hyperfine field.