Defects in ferrites studied by 57Fe NMR

Presence of defects in ferrites gives rise to a modification of the hyperfine field on nuclei of those iron ions, which are situated in the neighborhood of the defect. If the concentration of defects is small, satellite structure of the NMR spectra of Fe-57 nuclei is observed. Analysis of this satellite structure provides valuable information. In particular concentration of the defect, its distribution over various sublattices, magnetic moment and the valency may be obtained. In the present paper we describe how the analysis of the satellite structure is performed, summarize the requirements on the NMR experiment and illustrate the method using several examples of defects in the yttrium iron garnet.