Thermal diffusivity and thermal conductivity of $\mathrm{Bi}_{1-x}\mathrm{Gd}_x\mathrm{FeO}_3\,(x = 0$–$0.30)$ multiferroics

We have studied the thermal diffusivity and thermal conductivity of $\mathrm{Bi}_{1-x}\mathrm{Gd}_x\mathrm{FeO}_3$ multiferroics within the high temperature range of $300$–$1200$ K. We consider the dominant mechanisms of the heat transfer of phonons within the domain of ferroelectric and antiferromagnetic phase transitions and determine the temperature dependence of the mean free path of the phonons.