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Well-crystallized polycrystalline thin films of cubic barium titanate, BaTiO3, and strontium titanate, SrTiO3, have been prepared on the Ti-deposited flexible polymer film of polyphenylen sulfide in Ba(OH)2and Sr(OH)2aqueous solutions at temperatures between 120 and 180°C under saturated vapor pressures. The films were dense and lustrous like a mirror. The thicknesses of the films were in the range of 50-250 nm for the hydrothermal treatment time of 1-3 h at those temperatures. The grains were generally uniform and their typical average size for the film formed at 150°C for 1 h in 3N-Ba(OH)2was approximately 50 nm.

Single-crystal X-ray diffraction study under high pressures has been carried out on silver thiogallate, AgGaS2, to investigate the phase transition at about 42 kbar. The crystal of AgGaS2is tetragonal with the space group I2d having the cell dimensions a=5.7603(6) and c=10.299(2) Å under the ambient pressure. The high-pressure form has a similar unit cell to that of the ambient pressure form. The diffraction pattern around the [22] zone axis at 47 kbar indicated that the high pressure form has weak but clear hhlreflections which do not satisfy the systematic absence condition, 2h+l=4n, for the space group I2d. It has been concluded that the diamond glide planes parallel to {110} present in the ambient pressure form disappear in the high pressure form.

BaTiO3thin films have been prepared in situon Ti metal substrates by a hydrothermal electrochemical technique, where a direct current has been passed between the anode, Ti plate, and the cathode, Pt plate, in high-temperature, high-pressure Ba2+solutions. Dense thin films, 0.1?0.3 µm thick, which consist of cubic BaTiO3polycrystals without apparent pores or defects have been obtained under the following conditions: in 0.25?0.5 N-Ba(OH)2solutions above 100°C under saturated vapor pressures with the current density of 10?100 mA/cm2after 30?80 min. These films are paraelectric with the dielectric constant of ?300.

C-axis-oriented barium titanate (BaTiO3) epitaxial films with an atomically smooth surface have been fabricated on SrTiO3{100} substrates using the pulsed laser deposition technique. The crystal structure and epitaxial orientation of the films have been analyzed by means of 2?/? X-ray diffractometry and 4-circle X-ray diffractometry. The highly oriented and epitaxial crystallinity is also shown by means of Rutherford backscattering spectrometry which gave a ?minof 1.7%. The atomically smooth surface comparable to that of the SrTiO3substrate is revealed by means of atomic force microscopy. The breakdown electric field of the BaTiO3film is as high as 106V/cm.

Heteroepitaxial growth of BaTiO3films on SrTiO3single-crystal substrates was studied in Ba(OH)2solution under hydrothermal conditions above 450°C. The epitaxial relation, BaTiO3(hkl)//SrTiO3(hkl), was confirmed for the films on (100), (110), (111) and (210) faces of the SrTiO3crystals. Morphology of the grown surfaces faceted by {100} faces was directly affected by the indices of the substrate surface as a result of the epitaxial relation. In particular, monolithic films having a smooth surface were formed on SrTiO3(100) substrates.