1302.6739 (B. Y. Pan et al.)

Specific heat and thermal conductivity of ferromagnetic magnons in
Yttrium Iron Garnet    [PDF]

B. Y. Pan, T. Y. Guan, X. C. Hong, S. Y. Zhou, X. Qiu, H. Zhang, S. Y. Li

The specific heat and thermal conductivity of the insulating ferrimagnet Y$_3$Fe$_5$O$_{12}$ (Yttrium Iron Garnet, YIG) single crystal were measured down to 50 mK. The ferromagnetic magnon specific heat $C$$_m$ shows a characteristic $T^{1.5}$ dependence down to 0.77 K. Below 0.77 K, a downward deviation is observed, which is attributed to the magnetic dipole-dipole interaction with typical magnitude of 10$^{-4}$ eV. The ferromagnetic magnon thermal conductivity $\kappa_m$ does not show the characteristic $T^2$ dependence below 0.8 K. To fit the $\kappa_m$ data, both magnetic defect scattering effect and dipole-dipole interaction are taken into account. These results complete our understanding of the thermodynamic and thermal transport properties of the low-lying ferromagnetic magnons.

View original: http://arxiv.org/abs/1302.6739