High-Pressure Phase Diagram of NdFeAsO$_{0.9}$F$_{0.1}$: Disappearance of superconductivity on the verge of ferromagnetism from nd moments

TL;DR

This study explores how applying high pressure to NdFeAsO$_{0.9}$F$_{0.1}$ suppresses superconductivity and induces ferromagnetism, revealing a complex interplay between these states and a crossover in electronic behavior.

Contribution

It provides the high-pressure phase diagram of NdFeAsO$_{0.9}$F$_{0.1}$, showing the suppression of superconductivity and emergence of ferromagnetism, a novel insight into 1111-type materials.

Findings

Superconductivity disappears at ~21 GPa.

Ferromagnetism emerges beyond 21 GPa.

Resistivity shows a Fermi-liquid to non-Fermi-liquid crossover.

Abstract

We investigated transport and magnetic properties of NdFeAsO$_{0.9}$F$_{0.1}$ single crystal under hydrostatic pressures up to 50\,GPa. The ambient pressure superconductivity at $T_{c} \sim$ 45.4\,K is fully suppressed at $P_{c} \sim$ 21 GPa. Upon further increase of the pressure, the ferromagnetism associated with the order of rare-earth subsystem is induced at the border of superconductivity. Our finding is supported by the hysteresis in the magnetization $M$($H$) loops and the strong increase in the field cooled data, $M$($T$), toward low temperatures. We also show that the temperature evolution of the electrical resistivity as a function of pressure is consistent with a crossover from a Fermi-liquid to non-Fermi-liquid to Fermi-liquid. These results give access to the high-pressure side of the superconducting phase diagram in 1111 type of materials.