Field Re-entrant Superconductivity Induced by the Enhancement of Effective Mass in URhGe

TL;DR

This study investigates field re-entrant superconductivity in URhGe, revealing its dependence on effective mass enhancement near a critical magnetic field, and provides insights into the interplay between magnetic and superconducting phases.

Contribution

It demonstrates how effective mass enhancement induces re-entrant superconductivity in URhGe and analyzes its dependence on residual resistivity and resistivity coefficients.

Findings

Re-entrant superconductivity occurs near the magnetic transition field H_R.

Superconducting critical temperature T_sc and upper critical field H_c2 are strongly enhanced by effective mass.

The results suggest a link between effective mass, resistivity parameters, and superconductivity in heavy fermion systems.

Abstract

High quality single crystals of a ferromagnetic superconductor URhGe were successfully grown. The electrical resistivity was measured for the field along b-axis in the orthorhombic crystal structure in order to study precisely its field re-entrant superconductivity which occurs in the vicinity of the field $H_{\rm R}$, where the easy magnetization switches from $c$ to b-axis. The field re-entrant superconductivity of URhGe is analyzed with special focus on its dependence with the value of residual resistivity $\rho_0$ and the coefficient $A$ of $T^2$ term of the resistivity. The experimental results are well explained by a crude model related with the field dependence of the effective mass $m^\ast$, where the corresponding critical temperature $T_{\mathrm{sc}}(m^\ast)$ and the upper critical field $H_{\rm c2}$ are strongly enhanced. Discussion is made on the interplay between magnetic and superconducting phase diagram as well as the link between $T_{\mathrm{sc}}$ and $A$ in other heavy fermion superconductors.