Resonance Measurements in Magnetic Garnets

Abstract

The effective $g$ value, anisotropy constants, and line widths of single crystals of YIG, GdIG, SmIG, HoIG, ErIG, and YbIG have been measured over a range of temperatures from 1.5°K to 550°K by ferrimagnetic resonance. The temperature dependence of $K_1$ in both YIG and GdIG is satisfactorily represented by the model of an individual ion subject to a crystalline field in addition to a Weiss molecular field. The $g$ values of HoIG and ErIG appear to be in good agreement with the estimations of Kittel et al. for a ferrimagnetic system with one sublattice strongly damped. It has been found that SmIG and YbIG do not follow the predictions of the Kittel model, since different relative strengths of exchange and relaxation interactions seem to be involved.