Crystallographic orientation dependent dielectric properties of epitaxial BaTiO3 thin films

Epitaxial BaTiO3 ferroelectric films with (001), (110), and (111) orientations were, grown on SrRuO3 buffered SrTiO3 substrates via a radio-frequency magnetron sputtering method. The effects of the orientation on dielectric response were systematically investigated. We found that the (110)-oriented film exhibited the largest dielectric permittivity, tunability and phase transition temperature, whereas the (111)-oriented film demonstrated the best figure of merits if the dielectric loss was taken into consideration. The large anisotropic dielectric behavior, which is predominantly attributed to the differences of polarization states in these orientation engineered BaTiO3/SrTiO3 heterostructures, was observed. These results suggest the (111)-oriented film may be an attractive candidate for applications in dielectric tunable devices.