Thermophysical properties and phase transitions of ferroelectric PbFe$_{0.5}$Nb$_{0.5}$O$_3$ at high temperatures

The thermophysical properties of the ferroelectric PbFe$_{0.5}$Nb$_{0.5}$O$_3$ in the temperature range 300–800 K are studied. Anomalies in the heat capacity and thermal diffusion are found in the region of the diffuse ferroelectric transition $T_{\mathrm{c}}\approx$ 380 K, the Burns temperature $T_{\mathrm{d}}\approx$ 670 K, and the intermediate temperature $T^*\approx$ 470 K. The dominant phonon heat transfer mechanisms in a ferroelectric with a nanopolar structure.