Mössbauer-effect study of Mg-Al ferrites having a rectangular hysteresis loop

A Mossbauer-effect study was made of Mg-Al ferrites having a rectangular hysteresis loop. The replacement of Fe3+ ions by A13+ ions produces an additional component in the Mossbauer spectra, due to second-phase inclusions. The phase composition of the Mg-Al ferrite has a marked effect on the shape of the hysteresis loop. As the second-phase inclusions increase in relative importance, rectangularity coefficient D decreases. Local lattice distortion has a lesser effect on D. At high Al2O3 concentrations (above 15 mole%) in the Mg ferrite there is a sharp increase in the coercive force with increasing Al2O3 content. This increase is also due to second-phase inclusions.