Off-axis laser deposition and characterization of Ba1-xSrxTiO3 thin films

Thin films of Ba1-xSrxTiO3 were prepared by off-axis laser deposition on MgO (001) and YBa2Cu3O7-delta coated SrTiO3 (001) substrates. X-ray diffraction in Theta-2 Theta geometry shows (001) oriented film growth of Ba1-xSrxTiO3. The epitaxial film growth was proved by pole figures and reflection high-energy electron diffraction (RHEED) patterns. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) was used to investigate the deposition temperature dependence of surface roughness and grain size. Electrical properties were measured by a Sawyer-Tower circuit and the integration of polarization current. For a deposition temperature of 800 degrees C and an oxygen pressure of 0.4 mbar the BaTiO3 films show a remanent polarization of about 5 mu C/cm(2) at a coercive field of 55 kV/cm, dielectric constants of about 320 and dissipation factors of 0.02. The epsilon-T dependence was measured for different Ba-Sr stoichiometries. The Ba1-xSrxTiO3 films on MgO show optical properties near bulk values.