Temperature Dependence of the Spin-Wave Spectrum of Yttrium Iron Garnet

Abstract

The temperature dependence of the exchange constant D in the equation of the spin-wave spectrum has been measured from 4.2°K–500°K in single crystals of very pure yttrium iron garnet. The results are compared,with good agreement up to 325°K, to predictions based on an extension of the random phase approximation to a ferrimagnet.