Phase Transformations in Titanium Oxide Evaporated Films by Annealing

The process of the phase transformation of evaporated films of TiO 0.5 has been demonstrated by in situ annealing using an electron microscope. Single crystals of the δ-phase, whose structure is identified with Andersson's hexagonal model, precipitate during annealing. Crystal structure images in cooperation with the calculated images reveal that the inner parts of the δ-phase crystal have various thickness. The transition structures I and II having ordered vacancies of titanium and oxygen respectively also appear on annealing. The difference in the distortion of their lattices from the parent rock-salt type lattice suggests that the effective atomic volume of titanium is larger than that of oxygen in the crystal of the transition structure. The observed transformations, α-phase → δ ;phase → transition structure, are explained by consideration of the structural relationships among these phases.