Pulsed laser deposition of epitaxial ferroelectric PbZrxTi1-xO3/SrTiO3 andPbZrxTi1-xO3/SrRuO3 bilayers

Epitaxial ferroelectric PbZrxTi1-xO3 (PZT) thin films have been deposited b y pulsed laser deposition on LaAlO3 (001) substrates. The substrates were c overed in situ with a thin SrTiO3 seed layer before the PZT deposition. Wid e ranges of substrate temperature and oxygen partial pressure have been inv estigated in order to optimise structure and morphology. X-ray diffraction measurements revealed that epitaxial films with high crystalline quality we re obtained at temperatures ranging from 600 degrees C to 750 degrees C and oxygen pressures from 0.03 to 0.2 mbar. Within this range, flat morphologi es with rms roughness below 1 nm were observed by scanning electron and ato mic force microscopies, whenever oxygen pressure was kept below 0.1 mbar an d the films were 100 nm thick or less. A rougher columnar microstructure is obtained for thicker films and greater oxygen pressures. Ferroelectricity of the films has been tested in samples deposited on conductive SrRuO3 elec trodes. Typical remanent polarisations of 13 mu C/cm(2) and coercive fields of 47 kV/cm are obtained. (C) 2000 Elsevier Science B.V. All rights reserv ed.