Electronic and superconducting properties of the V-Os system

Low temperature specific heat results of the V-Os systems are presented and compared with the V-Ru system which has a similar constitution diagram. The disordered phase, rich in vanadium, is characterized by a decrease of the superconducting transition temperature Tsub(c) due to a decrease of the electronic coefficient γ when the impurity concentration increases. The B2 ordered phase which is stable for the number of d electrons N-barsub(d) approx. 5 is featured by low γ values. For N-barsub(d) = 5.5 the limit of existence of the B2 type structure is reached and a A15 type of structure appears (at high temperature) in the V-Os system, and the B2 type structure is distorted (martensitic transformation) in the V-Ru system. These phenomena are accompanied by high γ values and high superconducting transition temperatures. (author)