Phase transition behavior of BaTiO3 thin films using high-temperature x-ray diffraction

Ferroelectric BaTiO3 thin films have been fabricated on SrTiO3(001) substrate using pulsed laser deposition. In order to investigate the phase transition behavior of the thin films, we have conducted high-temperature x-ray diffraction in the process of heating and cooling. Lattice constants, degree of c-axis orientation and crystal quality of the thin films were characterized as a function of temperature. The results show that the temperature of tetragonal-to-cubic phase transition for a BaTiO3 thin film is much higher than that of BaTiO3 bulk single crystal, and the phase transition of BaTiO3 thin film occurs in a wide temperature range (from 500 to 800 °C). The tetragonal-to-cubic phase transition for BaTiO3 thin film is irreversible.