Wagner, K. (Corresponding author) ; Institut für Festkörperforschung (Jülich) ; Universität (Köln)

1994
Forschungszentrum Juelich Juelich

Report No.: Juel-2947

Abstract: 57Fe-NMR is applied to study impurities and defects in yttrium iron garnet (Y3Fe,0I2), both in films grown by liquid phase epitaxy and in sintered polycrystalline samples. The NMR spectra and the nuclear relaxation have been investigated. Impurities can enter the garnet structure from the basic oxides (Ca,Si), the flux (Pb) or the crucible (pt). A cation defect in the garnet structure causes a characteristic satellite structure in the NMR spectrum besides the main line caused by the unpertubed iron nuclei. The satellite structure depends on the lattice site where the defect is located. The satellite intensity is proportional to the defect concentration. The assigrunent of a given satellite to a specific defect can be made within a series of samples where the defect concentration is changed. Threevalent impurity cations cause satellites with a linewidth equal to the corresponding main line, whereas charged impurities produce broader satellites. This shows a correlation of at least one other defect in the neighborhood of the charged one achieving a local charge compensation.

Keyword(s): NMR (nuclear magnetic resonance) ; garnet ; defect analysis ; impurity

1. Institut für Festkörperforschung (IFF)