Study of liquid-infiltrated Nb-Sn superconducting composite wire by specific-heat measurements

• Published in: Journal of applied physics Vol. 60; no. 11; pp. 3978 - 3981
• Main Authors: HELLMAN, F, HONG, M, HULL, G. W. JR, GEBALLE, T. H
• Format: Journal Article
• Language: English
• Published: Woodbury, NY American Institute of Physics 01.12.1986
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals, alloys and compounds (a15, 001c15, laves phases, chevrel phases, borocarbides, etc.); Metals, semimetals and alloys; Metals. Metallurgy; Other techniques and industries; Physics; Specific materials; Superconducting materials (excluding high-tc compounds); Superconductivity; Specific heat; Annealing; Wire; Composite material; Superconduction transition
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.337520

The results of specific-heat and inductive Tc measurements on reacted liquid-infiltrated superconducting composite wires with an overall composition of Nb-8 at. % Sn are presented. It is found that approximately 23 wt. % of the reacted wire is high Tc A15 phase, a result not expected from the accepted equilibrium phase diagram. The relatively sharp superconducting transition at 18 K is indicative of a uniform stoichiometric Nb-25 at. % Sn composition in the A15 phase. The large fraction of high Tc material in these wires is due to taking advantage of the rapid diffusion of Nb in liquid Sn. From a detailed analysis of the specific heat, comments on the reaction process are made. Implications for the equilibrium phase diagram are discussed.