Superconducting state in (W, Ta)5SiB2

Abstract

We characterize the superconducting state in a boro-silicide (W, Ta)5SiB2, with T c of 6.5 K by means of magnetization, electrical resistivity, and specific heat measurements. As x increased, the transition temperature T c abruptly enhances from 5.8 to 6.5 K. The magnetization versus magnetic field ( M - H ) curve indicated that (W, Ta)5SiB2 was a conventional type-II superconductor. The estimated lower critical field H c1(0) and upper critical field H c2( T ) are about 121 Oe and 14.7 kOe, respectively. The penetration depth λ(0) and coherence length ξ(0) are calculated to be approximately 369 and 14.9 nm, respectively, using Ginzburg-Landau (GL) equations. Specific heat data shows the superconductivity in W4.5Ta0.5SiB2 belongs to a week-coupling BCS superconductor. Finally, we discuss the increasing of T c in of (W, Ta)5SiB2 system.