FORMATION OF POLYCRYSTALLINE BATIXOY COMPOUNDS IN BARIUM IMPLANTED TIO2

Barium (Ba2+) ions of 280 and 30 keV energies were implanted at room t emperature in TiO2 rutile single crystals with a total fluence of 1.2 X 10(17) ions cm(-2) and subsequently thermally annealed up to 1150 de grees C in O-2 flow or in air during 1 h. Some samples were post-impla nted with oxygen (O+) ions of 45 and 30 keV energies. The annealing ef fects in the implanted layer were investigated by Rutherford Backscatt ering Spectrometry in channeling geometry, X-ray diffraction at glanci ng incidence and Transmission Electron Microscopy. The thermal treatme nts performed at 1150 degrees C lead to the formation of two new phase s: (a) BaTi4O9 obtained after annealing in air, (b) BaTi4O9 and BaTi2O 5 after annealing in O-2 flow. The oxygen post-irradiation seems to mo dify mainly the epitaxial relation between the new phases and the matr ix.