Superconducting properties of W7Re13B compound

We present both experimental and theoretical investigations of the magnetic properties and electronic structure of the recently discovered superconductor W7Re13B. We determine the lower and the upper critical fields H-c1(0) = 8.77 mT and H-c2(0) = 11.8 T, which correspond to a penetration depth lambda = 2675 angstrom and to a coherence length xi = 52 angstrom. The Ginzburg-Landau parameter, kappa is equal to 51. The effect of pressure on W7Re13B is negligible. This can be attributed to small changes in the density of states under pressure, or alternatively, to a low compressibility of this hard compound. (C) 2007 Elsevier B.V. All rights reserved.