CHEMICAL EFFECTS IN TIO2 AND TITANATES DUE TO BOMBARDMENT WITH AR-2(+) IONS OF DIFFERENT ENERGIES (3.5-10 KEV)( AND O)

Compositional and chemical changes in TiO2 and Pb, Ni, Al and Ba titan ates induced by bombardment with Ar+ and O-2(+) ions of different ener gies have been studied quantitatively by XPS. An increase of preferent ial loss of oxygen and, in case of PbTiO3, of lead has been observed w hen increasing the Arf ion energy from 3.5 to 10 keV. Because of oxyge n loss, Ti4+ species reduce to Ti3+ and Ti2+. In addition, the loss of oxygen from PbTiO3 and NiTiO3 leads to the metallic state of nickel a nd lead, whereas aluminium and barium in Al2TiO5 and BaTiO3 maintain t heir chemical state (i.e., Al3+ and Ba2+). Bombardment with O-2(+) ion s of PbTiO3 and NiTiO3 leads to a partial reduction of Pb and Ni. This metallization and the preferential loss of lead are more efficient at higher ion energies for both, O-2(+) and Ar+ bombardment. The results are discussed in terms of chemical stabilities and the possibility of oxygen diffusion in the bombarded oxides.