Abstract
Oxide artificial superlattices have the potential to drastically improve properties of conventional materials. We have demonstrated BaTiO3/SrTiO3 artificial superlattices made by an MBE process showed giant dielectric permittivity. However, the MBE process is not suitable for industrial production process because of it low deposition rate. Therefore in this study, we try to fabricate BaTiO3/SrTiO3 multi-layered films on MgO (001) substrates by RF sputtering method. BaTiO3 and SrTiO3 were alternately deposited using two ceramic targets. A solid solution film with a chemical composition of (Ba0.5Sr0.5)TiO3 was also prepared. X-ray pole figures indicated that the films had an epitaxial relation with the substrate. Planer electrodes were formed on the films using a lithography technique. The complex admittance of the thin film were measured with an impedance analyzer at 1MHz to 3GHz. Dielectric permittivity of the films was determined from admittance data using an electromagnetic field analysis. The film of [(BaTiO3)10/(SrTiO3)10]50 showed a high dielectric constant of 850 in comparison with the solid solution film.
