Suppression of high-temperature thermal conductivity due to electron-lattice coupling in PrAlO3, Tb2Ti2O7, and Dy3Al5O12

Abstract

Abstract Thermal conductivities (κ) above 300 K are presented for a series of RAlO3 perovskites, R 2Ti2O7 pyrochlores, and R 3Al5O12 garnets, where R is a rare earth. We find unusual temperature dependence and suppression of κ in PrAlO3, Tb2Ti2O7, and Dy3Al5O12, which arise from interactions between the lattice phonons and electronic energy levels of R ions. These results indicate that proper consideration of electron-lattice coupling is necessary in assessing the high-temperature κ of R-based oxides, which are widely being examined for applications to thermal barrier coatings.