ANALYSIS OF MAGNETIC AFTER-EFFECT SPECTRA IN BARIUM FERRITES

The prominent peaks occurring in the magnetic after-effect (MAE) spect ra of barium ferrites (BaO . n Fe2O3) of various compositions, 5 < n < 123, above the Verwey-temperature (T(V) = 125 K) are numerically anal yzed using least-squares fitting techniques. Comparison of the so-dete rmined process parameters with those obtained from quenched and electr on-irradiated magnetite shows that, also in the presence of Ba, the sa me basic point defect relaxation mechanisms are active, i.e. reorienta tion of cation interstitial configurations at T = 170 and 240 K, with activation enthalpies of 0.56 and 0.73 eV, and of various vacancy conf igurations near T = 300 and 360 K with enthalpies of 0.84 and 0.93 eV and with 1.05 eV, respectively.