The structure of BaTiO3 and BaTiO3-YBa2Cu3O7-delta thin films studied by X-ray triple-axis diffraction

The structures of BaTiO3 thin films and BaTiO3/YBa2Cu3O7-delta bilayer film s grown on SrTiO3 and LaAlO3 substrates, respectively by pulsed laser depos ition, have been investigated by X-ray triple-axis diffraction. The orienta tion, the interface mismatch and strain status, and the in-plane and perpen dicular lattice constants of the epilayers have been determined by reciproc al space map analysis. The results show that both the lattice constants and the structural imperfections of the BaTiO3 layers are relevant to the oxyg en partial pressure. The a(perpendicular to)/a(parallel to) increases while the full width at half maximum (FWHM) of the rocking curves decreases with the decrease in the partial oxygen pressure.