Non-equilibrium crystalline superconductors in Zr-Si binary alloys rapidly quenched from melts

Abstract

The new non-equilibrium superconductor with a b c c structure has been found in rapidly quenched Zr-Si alloys. The silicon content in the b c c alloys was limited to the narrow range between 8 and 11 at%. The b c c alloys showed a superconducting transition whose temperature increased from 3.20 to 3.84 K with decreasing silicon content. The upper critical magnetic field and the critical current density for Zr₉₂Si₈ alloy were of the order of 3.58 × 10⁶ Am⁻¹ at 2.0 K and 3.3 × 10⁻² Am⁻² at 2.42 K in the absence of an applied field. The upper critical field gradient at the transition temperature and the electrical resistivity at 4.2 K were about — 1.82 × 10⁻¹ Am⁻¹ K⁻¹ and about 150 μΩcm. The Ginzburg-Landau parameter κ and coherence length ξ_GL (0) were estimated to be about 65 and 6.3 nm, respectively, from these experimental values by using the Ginzburg-Landau-Abrikosov-Gorkov theory and hence it is concluded that the present b c c alloys are extremely “soft” type-II superconductors with a high degree of dirtiness.