Improvement of dielectric and ferroelectric properties by laser sintering of pulsed EPD BaTiO3 films

BaTiO3 (BT) powder was coated with SiO2 using Sto center dot ver method. Then BT films were prepared on Au/stainless steel substrates by pulsed electrophoretic deposition using this SiO2/BT powder aqueous suspension. The resulting BT films were sintered using a semiconductor laser (450 nm wavelength, 3.2 x 104 W/cm2 maximum power, 100 mu m spot diameter). The BT film was sintered with 12% laser power, but not sintered when the laser power less than 11%. The BT crystalline phase did not change during sintering. Sintering and peeling off of the film were observed when the laser power was greater than 13%. By laser sintering, the BT film thickness decreased to 49%. The dielectric constants of the electrophoretic deposited film and laser sintered film at the Curie temperature were, respectively, 730 and 2340. The electrodeposited film had a coercive field of 80.35 kV/ cm, with remanent polarization of 0.032 mu C/cm2. The laser-sintered film had a coercive field of 71.3 kV/cm and remanent polarization of 9.51 mu C/cm2. Laser irradiation promoted sintering of the BT film, and thereby dras-tically improved the BT film dielectric and ferroelectric properties.