The Magnetization Mechanism in Single-Crystal Garnet Slabs Near the Compensation Temperature

The magnetization mechanism has been studied in detail in single-crystal slabs of (111), (110) and (100) samples of gadolinium iron garnet (GdIG) near the compensation temperature. Using Faraday-effect and induction-type hysteresigraphs, the hysteresis loops have been measured in the sample plane and perpendicular to it, respectively. Measurements have been made at various temperatures, thus allowing the effects of variation of the saturation magnetization to be studied. In this way different relative magnitudes of shape and crystal anisotropy are obtained. Also, the effects of strain anisotropy variation are studied on the (111) sample. The hysteresis loops are correlated with the observed domain structures and a satisfactory theoretical model is described. Based on these studies, it is possible to estimate the approximate domain wall thickness and energy in GdIG. Finally, an estimate of the exchange constant is made which is comparable with other estimates.