Comment on the paper 'Superconductivity in the A15 compounds V3Ge1-xMxwith M=Al, Si and Sb' by A. Oota et al

Abstract

For original paper see ibid., vol.14, p.2097 (1984). The author criticises the efforts of Oota et al. to analyse observed changes in the superconducting critical temperature Tc and residual resistivity rho 0 in terms of the electron-to-atom ratio e/a for a range of pseudobinary A15 compounds based on V3Ge, on the grounds that in such compounds, Tc is strongly dependent on both the exact composition and the degree of crystallographic long-range order. The addition of third elements, he maintains, may influence either of these factors. He also questions the claim of Oota et al. that their specimens were of a single A15 phase, and suggests metallographic examination would have shown they contained approximately 10% V5Ge3.