The order-disorder phase transition in sub-stoichiometric compositions, VOy, was studied for the first time in situ by using the Faraday method with a pendulum magnetic balance of Domenically type. A minimum was found in the temperature dependence of the magnetic susceptibility of samples with various compositions at about 700K. X-ray diffraction analysis performed before and after measuring the magnetic susceptibility confirmed the change in the structure of the monoxide and the possibility of atom-vacancy processes occurring upon cooling and heating the samples.

Ordering of Structural Vacancies in Vanadium Monoxide of Substoichiometric Composition. D.A.Davydov, S.Z.Nazarova, A.A.Valeeva, A.A.Rempel: Bulletin of the Russian Academy of Sciences – Physics, 2007, 71[5], 677-80