Specific Heat of Yttrium Iron Garnet from 1.5° to 4.2°K

Abstract

The specific heats of two samples of yttrium iron garnet have been measured between 1.5 and 4.2\ifmmode^\circ\else\textdegree\fi{}K. The data have been analyzed into lattice- and spin-wave contributions characterized, respectively, by the Debye temperatures ${\ensuremath{\Theta}}_{1}=538\ifmmode^\circ\else\textdegree\fi{}$K, ${\ensuremath{\Theta}}_{2}=567\ifmmode^\circ\else\textdegree\fi{}$K, and by ${D}_{1}=0.81\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}28}$ erg-${\mathrm{cm}}^{2}$, ${D}_{2}=0.85\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}28}$ erg-${\mathrm{cm}}^{2}$, where $D$ is defined by the dispersion relation for spin waves, $\ensuremath{\hbar}\ensuremath{\omega}=D{k}^{2}$.