Phase transition of BaTiO3 thin films

The phase transition of ferroelectrics is one of their most important bulk-nature attributes. In well-epitaxial ferroelectric thin films, the crystal structures are highly strained and the ferroelectric phase transitions tend to dissappear because of an epitaxial effect. We investigated the epitaxial effect by structural analysis and clarified the growth conditions of BaTiO3 films that show their bulk nature. As a result, epitaxial crystals of BaTiO3 with a thickness of 67 A were grown on a MgO substrate with a Pt electrode by the activated reactive evaporation method. A clear thermal anomaly was observed at 140 degreesC that suggests the phase transition of BaTiO3.