MAGNETIC DEFECT STRUCTURE OF IRON-RICH FEXO

Mossbauer spectra were recorded at 80 and 4.2 K for FexO (x > 0.95) sa mples that had been synthesized at 1000 degrees C and pressures up to 10 GPa. The spectra, which consist predominantly of six broadened line s, were fit to three magnetic components: bulk Fe2+ defect cluster Fe2 + and defect cluster Fe3+. Mean hyperfine parameter values for bulk Fe 2+ were calculated using second-order perturbation theory, and correla tions between fluctuations were determined from the mean-square linewi dths. Implications for the magnetic defect structure of FexO are discu ssed.