Anisotropic vortex pinning in the layered intermetallic superconductor CaAlSi

Abstract

We have studied anisotropic magnetic properties of layered intermetallic superconductor CaAlSi with moderate anisotropy. Near the upper critical field there is a prominent peak effect for H||c at low temperatures and it becomes weaker for H||ab. The estimated correlation length Lc suggests the presence of three-dimensional collective pinning around the peak effect. The critical current densities for H||c and H||ab have been extracted and compared. Flux pinning mechanism in CaAlSi is anisotropic. Collective core pinning is observed for H||c whereas there is a signature of deviation from it for H||ab. The vortex phase diagram, including the upper critical field, irreversibility field, and peak field, has been studied. The thermodynamic critical field and Ginzburg-Landau parameter have been estimated from the equilibrium magnetization. The nature of scaling of the maximum pinning force densities with the thermodynamic critical field has been discussed. The temperature dependence of London penetration depth is consistent with single fully gapped state in CaAlSi.

Source-reported materials — not catalogue approval

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