Characterization of Natural and Synthesized FeTiO₃ Crystals With RBS/PIXE/XRD

Natural FeTiO₃ (illuminate) and synthesized FeTiO₃, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO₃ were grown under the pressure control of CO₂ and H₂ mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO₃ single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe₂O₃ even during the annealing procedure. Natural FeTiO₃ contains several kinds of impurities such as Mn, Mg, Na and Si. The synthesized samples contain Al, Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO₃ or in mixed phase between ilmenite and hematite.