Formation of artificial BaTiO3/SrTiO3 superlattices using pulsed laser deposition and their dielectric properties

We have formed strained dielectric superlattices of BaTiO3 (BTO) and SrTiO3 (STO) by a pulsed laser deposition technique. A large strain of 400–500 MPa is introduced at the interface between the BTO and STO layers. A large dielectric constant of 900 was observed with a stacking periodicity of 2 unit cells/2 unit cells. The superlattices show drastically different electrical behavior from that of the solid solution (Sr,Ba)TiO3 films. Broad maxima of the dielectric constants occur around 40–50 °C and the values remain large even for a temperature above 200 °C.