Attempts to prepare vanadium based oxide superconductors

Preparation of a vanadium-based oxide compound of the type YBa2Cu3Ox was investigated. Its crystal structure and electrical properties were studied. Preparation was attempted in three different ways. The XRD patterns of all the products were surprisingly identical; they revealed an orthorhombic unit cell, and the d-values are tabulated. The oxidation state of vanadium in the compound was established at +3, and the formula could be written as YBa2V3O8. In spite of the fact that the new compound was very similar to 1, 2, 3 oxide in respect of perovskite structure, t-factor and orthorhombic unit cell of comparable dimensions, it does not show metallic characteristics let alone superconducting behaviour. This is probably due to the fact that vanadium stabilises in a single oxidation state of +3 in this compound whereas the requirements for superconductivity appears to be the ability of a valence state to disproportionate into a lower and a higher one. 4 refs.