Evidence of a new phase formation (BaTi4O9) by barium implantation into TiO2

Barium ions of 140 keV energy were implanted at room temperature in TiO2 (rutile) with a fluence of 1017 ions cm−2. Isochronal heat treatments were carried out in air at 1000, 1100 and 1150°C for 1 h. Rutherford backscattering spectrometry (RBS) is channeling geometry, X-ray diffraction at glancing incidence and X-ray photoemission spectroscopy (XPS) were undertaken to the physico-chemical characterization of the implanted rutile. The annealing at 1150°C leads to the formation of a new phase which hae been identified as BaTi4O9 with an average grain size of about 28 nm.