Electronic phase diagram of NdFe1-xRhxAsO

TL;DR

This study maps the electronic phase diagram of Rh-doped NdFeAsO, revealing suppression of structural and magnetic transitions and the emergence of superconductivity with a dome-shaped Tc curve peaking at 18K.

Contribution

It provides the first detailed phase diagram of Rh-doped NdFeAsO, showing how Rh doping induces superconductivity despite lattice distortions.

Findings

Superconductivity appears at Rh doping level x ≈ 0.05.

Maximum Tc of 18K occurs at x = 0.1.

Resistivity shows Kondo-like behavior above Tc.

Abstract

We report on the electrical resistivity, thermoelectric power and electronic phase diagram of rhodium-doped NdFeAsO. Rhodium doping suppresses the structural phase transition and spin density wave observed in the undoped material, and superconductivity emerges at x close to 0.05, despite the distortion of FeAs4 tetrahedra induced by the large size difference between Rh and Fe elements. The Tc(x) curve is dome-like, and the highest Tc is reached at x = 0.1, with Tconset = 18K. An upturn of the electrical resistivity above Tc has been observed, with a Kondo like behaviour above Tc and a Fermi-liquid behaviour close to room temperature.