Effects of superconducting gap anisotropy on the flux flow resistivity in Y(Ni_{1-x}Pt_x)_2B_2C

TL;DR

This study investigates how superconducting gap anisotropy influences flux flow resistivity in Y(Ni_{1-x}Pt_x)_2B_2C, revealing that gap anisotropy significantly enhances energy dissipation in vortex cores.

Contribution

It demonstrates experimentally that superconducting gap anisotropy affects flux flow resistivity, providing new insights into vortex dynamics in anisotropic superconductors.

Findings

Flux flow resistivity in pure YNi_2B_2C is twice the expected value.

Pt doping reduces gap anisotropy and aligns resistivity with conventional models.

Energy dissipation in vortex cores is strongly influenced by gap anisotropy.

Abstract

The microwave complex surface impedance Z_s of Y(Ni_{1-x}Pt_x)_2B_2C was measured at 0.5 K under magnetic fields H up to 7T. In nominally pure YNi_2B_2C, which is a strongly anisotropic s-wave superconductor, the flux flow resistivity \rho_f calculated from Z_s was twice as large as that expected from the conventional normal-state vortex core model. In Pt-doped samples where the gap anisotropy is smeared out, the enhancement of \rho_f is reduced and \rho_f approaches to the conventional behavior. These results indicate that energy dissipation in the vortex core is strongly affected by the anisotropy of the superconducting gap.