Scattering of Magnons and Phonons in the Thermal Conductivity of Yttrium Iron Garnet

Abstract
Expressions have been derived for magnon-phonon scattering relaxation times for different cases as a function of temperature and wave vector using the theory of Sinha and Upadhyaya. The appropriate relaxation time is used in the determination of the effective relaxation time for magnons, and the thermal conductivity of yttrium iron garnet has been calculated in the temperature range 0.5 to 20°K using a quadratic dispersion law for magnons and a Debye spectrum for phonons.