Ferromagnetic quantum critical point in UCo1-xFexGe

TL;DR

This study investigates the evolution of magnetic and electronic properties in the UCo1-xFexGe series, revealing a ferromagnetic quantum critical point at x ≈ 0.22 where non-Fermi liquid behavior emerges.

Contribution

It provides a comprehensive phase diagram of UCo1-xFexGe, identifying a ferromagnetic quantum critical point induced by Fe substitution and its associated non-Fermi liquid phenomena.

Findings

Fe substitution increases Curie temperature initially

Superconductivity is rapidly suppressed with Fe doping

A quantum critical point occurs near x=0.22 with non-Fermi liquid behavior

Abstract

We have carried out a comprehensive study of the UCo1-xFexGe series across the entire range of compositions 0 <= x <= 1, and report the results of x-ray diffraction, magnetization, specific heat, and electrical resistivity to uncover the T-x phase diagram. Substitution of Fe into UCoGe initially results in an increase in the Curie temperature and a rapid destruction of the superconductivity. Near x = 0.22, the ferromagnetic transition is suppressed to zero temperature at an apparent ferromagnetic itinerant electron quantum critical point, where the temperature dependence of the electrical resistivity and specific heat in this region reveal non-Fermi liquid behavior.