Determination of structure factors of disordered vanadium monoxide crystals by the intersecting-Kikuchi-line and critical-voltage methods

The concentration of vanadium atoms at interstitial tetrahedral sites in disordered VO0.82 and VO1.20 crystals has been determined by use of both the intersecting-Kikuchi-line method and the critical-voltage method. It is shown that not only the structure factor but also the temperature factor can be determined by combining the two methods. From the structure-factor values obtained, the existence of interstitial vanadium atoms is confirmed for the disordered VO1.20, supporting the assumption that the defect cluster typical of the ordered phase persists in the disordered state, whereas the interstitial concentration in the disordered VO0.82 is found to be nearly zero. For VO1.20 and VO0.82 the values of 1.21 ± 0.12 and 1.05 ± 0.10 A2 respectively at room temperature were obtained for the B factor which includes contributions from static atom displacements as well as the effect of thermal vibrations.