Reentrant superconductivity in URhGe

TL;DR

This paper presents a phenomenological model explaining reentrant superconductivity in URhGe, showing how magnetic fluctuations near a first-order transition induce superconductivity at specific magnetic fields and temperatures.

Contribution

It introduces a Landau theory-based description of URhGe's phase diagram, highlighting the role of magnetic fluctuations in reentrant superconductivity near a first-order transition.

Findings

Reentrant superconductivity occurs near the first-order transition line.

Magnetic susceptibility increases near the transition, stimulating superconductivity.

Superconducting transition temperature decreases at the ferromagnet-paramagnet phase boundary.

Abstract

There is presented a phenomenological description of phase diagram of ferromagnet superconductor URhGe. In frame of the Landau phenomenological theory it was found that phase transition between anisotropic ferromagnetic and paramagnetic states under strong enough magnetic field perpendicular to direction of easy magnetization changes from the second to the first order type. It is shown that magnetic susceptibility corresponding to longitudinal magnetic fluctuations strongly increases in vicinity of the first order transition stimulating reentrance of superconducting state. The reentrant superconductivity observed near the first order transition line at temperatures about twice lower than the tricritical point temperature exists both in ferromagnet and paramagnet state. The critical temperature of transition to superconducting state falls down at intersection with line of ferromagnet-paramagnet phase transition.