Anisotropic Ginzburg-Landau scaling of Hc2 and transport properties of 112-type Ca0.8La0.2Fe0.98Co0.02As2 single crystal

TL;DR

This study synthesizes high-quality Ca0.8La0.2Fe0.98Co0.02As2 single crystals, investigates their anisotropic superconducting properties, and reveals insights into their transport behavior and scattering mechanisms through Ginzburg-Landau scaling and Hall effect analysis.

Contribution

It demonstrates the anisotropic Ginzburg-Landau scaling of Hc2 and transport properties in 112-type superconductors, providing new understanding of their anisotropy and scattering behavior.

Findings

High critical current density exceeding 2×10^6 A/cm² at 5 K.

Successful scaling of magnetoresistance with the Hall angle.

Nonmonotonic temperature dependence of the Hall coefficient.

Abstract

High-quality single crystal of Ca0.8La0.2Fe0.98Co0.02As2 has been successfully synthesized using a self-flux method. The magnetization measurement reveals a second peak effect and high critical current density exceeding 2*10^6 A/cm2 at 5 K(self-field). The upper critical field anisotropy was systematically studied by measuring the electrical resistivity under various magnetic fields and angles. The angle dependent magnetoresistance, by choosing an appropriate anisotropy parameter within the framework of the anisotropic Ginzburg Landau (AGL) theory, can be scaled onto one single curve. In the normal state, the negative Hall coefficient shows strong but nonmonotonic T-dependence through a minimum at 175 K. Moreover, it is shown that the magnetoresistance apparently violates the semiclassical Kohler's rule below 175 K but can be well scaled by the Hall angle instead. This suggests either the change of carriers with T or the exotic anisotropic scattering in the system.