Production and Superconducting Properties of Diffusion Coatings of Indium, Cadmium, Lead, Thallium, Bismuth, and Zinc on Vanadium

Abstract

The interaction of In, Cd, Pb, Tl, Bi, and Zn vapor with vanadium wire is studied after holding isothermally for 1 to 20 h at 1000 to 1200° in evacuated quartz ampoules. X-ray analysis of the resultant binary diffusion coatings reveals the formation of V₃In (a = 5.28-5.56 Å), V₃Cd (a = 4.92-4.95 Å), V₃Pb (a = 4.87 Å), V₃Tl (a = 5.21-5.25 Å), and V₃Bi (a = 4.72 Å), with the Cr₃Si structure. The existence of a compound V₃Zn with an analogous structure appears quite likely. The x-ray diffraction pictures of the coatings also show the lines of vanadium (the base) and those of a third phase, the crystal structure of which remains unsolved. The critical superconducting temperature of the compound V₃Zn obtained by the diffusion method is 13.9°K. The rest of the compounds obtained are not superconducting above 4.2°K.