Phase transitions and domain stabilities in biaxially strained (001) SrTiO3 epitaxial thin films

We applied phase-field approach to investigate both ferroelectric and antiferrodistortive transitions in (001) SrTiO3 epitaxial thin films that are strained biaxially. A domain/phase stability diagram of misfit strain-temperature was constructed for equibiaxially strained (001) SrTiO3 thin films, which exhibits significant differences from previous diagrams obtained using thermodynamic analysis of a single domain. For unequibiaxially strained (001) SrTiO3 thin films, misfit strain-misfit strain domain stability diagrams at several representative temperatures were obtained. The predicted phase transitions, domain stabilities, and domain structures in three different SrTiO3 thin films under either equibiaxial or unequibiaxial strains agree well with experimental observations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3488636]