FORMATION OF BI-BASED LAYERED PEROVSKITE OXIDE-FILMS BY A LASER-ABLATION TECHNIQUE

Bi-based layered perovskite oxide films (SrBi2Ta2O9) have been formed on the Nb-SrTiO3 substrate or Bi2Sr2 CuO6 superconducting bottom electrode with c-axis perpendicular to the substrate surface. The dielectric constants of the c-axis oriented SrBi2Ta2O9 films deposited on the Nb-SrTiO3 substrate are as high as 100 and remain constant at an applied frequency from 10(2) to 10(6) Hz. Furthermore, an artificially Bi-based layered perovskite structure can be constructed by the layer-by-layer successive deposition technique. The BaTiO3 or SrTiO3 layer is inserted artificially between the double Bi2O2 layers. The formation of ''artificially constructed ferroelectric films'' by a layer-by-layer deposition method will be discussed and an essential approach to elucidate the mechanism of ferroelectricity.