Specific heat and thermal conductivity of BaTiO3 polycrystalline thin films

Abstract

The results of measurements by the ac heater-probe method of the specific heat and thermal conductivity of polycrystalline BaTiO3 films with thickness between 1 and 0.1 μm in a temperature range 120–440 K are presented. In the heating and cooling runs, the phase transition anomalies of the thermal properties in the region of each phase transition in the sequence of symmetry change m3m-4mm-mm2-3m have been observed. A temperature hysteresis is observed, which is the signature of the first order phase transitions. As film thickness decreases, anomalies shift to lower temperatures and became smeared.