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

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.

6 pages, 4 figures