PbTiO3SrTiO3, and PbTiO3-Al2O3 composite and multilayer films prepared by sol-gel technique

PbTiO3 and SrTiO3 single phase films and PbTiO3-Al2O3 composite and multila yer films were prepared by the sol-gel method using dip- and spincoating de position techniques. The films were characterized by optical microscopy, X- ray diffractometry, Alpha Step profilometer, Rutherford back-scattering and Fourier transform far infrared spectroscopy. It was found that the presenc e of Al2O3 in composite films blocks the PbTiO3 crystallization even at the temperature 800 degrees C whereas in multilayer films the crystallization is retarded to a certain extent only. FT FIR spectroscopy has revealed in P bTiO3 films the well-pronounced soft mode at frequency 82cm(-1) slightly lo wer than in bulk crystals which indicates some compressive internal stresse s. In SrTiO3 films the effective soft mode damping increases with decreasin g film thickness, which demonstrates the role of stresses induced by the su bstrate.