Disorder–order phase transition in nanocrystalline titanium monoxide with two-sublattice ordering of structural vacancies

Abstract

Atomic-vacancy ordering was achieved via prolonged annealing of nanocrystalline nonstoichiometric titanium monoxide TiOy possessing the average crystal size of ∼30 ± 10 nm in vacuo in the temperature range of 300–1200 K. The XRD and HRTEM data revealed the ordering based on the orthorhombic super-structures of M2X3 and M3X2 types (space group Immm), which are derived from the B1 structure of disordered cubic phase of γ-TiO.