Anisotropy of hyperfine field in diamagnetically substituted YIG

The results of the nuclear magnetic resonance of ⁵⁷Fe in Al-, Ga- and In-substituted Y₃Fe₅O₁₂ garnets are reported. When diamagnetic Ga³⁺ or Al³⁺ ions are substituted for tetrahedral Fe³⁺ ions, four satellite lines in the NMR spectrum of octahedral Fe³⁺ ions appear. The substitution of In³⁺ ions for octahedral Fe³⁺ ions leads to three satellite lines in the spectrum of tetrahedral Fe³⁺ ions. The hyperfine fields of these satellites are explained using the independent bond model for the hyperfine interaction. Suprisingly large change of the anisotropic part of the hyperfine field relative to the isotropic one was found.