Thermal diffusion and heat conductivity of BiFeO$_3$ and Bi0.95La$_{0.05}$FeO$_3$ multiferroics at high temperatures

The thermal diffusion and heat conductivity of BiFeO$_3$ and Bi$_{0.95}$La$_{0.05}$FeO$_3$ multiferroics at high temperatures ($300$–$1200$ K) have been examined. The dominant mechanisms of phonon heat transfer in the region of ferroelectric and antiferromagnetic phase transitions have been revealed. The temperature dependence of the mean free path of phonons has been determined.