Heat transfer processes in multiferroics Bi$_{1-x}$Ho$_{x}$FeO$_{3}$ ($x$ = 0–0.20)

The thermal diffusivity and thermal conductivity of multiferroics Bi$_{1-x}$Ho$_{x}$FeO$_{3}$ ($x$ = 0–0.20) have been studied in the high-temperature region of 300–1200 K. It is established that alloying with the rare-earth element (holmium) strongly increases the specific heat in a wide temperature range $T>$ 300 K and significantly changes temperature anomalies of the thermal diffusion and thermal conductivity near phase transitions. Dominant mechanisms of phonon heat transfer near the ferroelectric and antiferromagnetic phase transitions are considered. The temperature dependence of the mean free path is determined. The results obtained are discussed along with the structural investigation data.