Coexistence of Antiferromagnetism and Superconductivity in PrFeAsO$_{1-\delta}$

TL;DR

This study reveals that in PrFeAsO$_{1-\delta}$, antiferromagnetism of Pr$^{3+}$ ions coexists with superconductivity below 14 K, with anisotropy increasing near the critical temperature, challenging previous neutron study predictions.

Contribution

The paper demonstrates coexistence of antiferromagnetism and superconductivity in PrFeAsO$_{1-\delta}$ and proposes a new magnetic structure inconsistent with earlier neutron studies.

Findings

Antiferromagnetism coexists with superconductivity below 14 K.

Superconducting anisotropy increases near T_c.

New magnetic structure differs from previous neutron study predictions.

Abstract

A high-quality PrFeAsO$_{1-\delta}$ single crystal ($T_{\rm c}=44$ K) has been investigated by the magnetic torque. Antiferromagnetism of the Pr$^{3+}$ ions was found to coexist with superconductivity in PrFeAsO$_{1-\delta}$ at temperatures below $T_\mathrm{N}=14$ K. We predict a magnetic structure that is not in accordance with earlier neutron studies performed using polycrystalline nonsuperconducting specimens. As the temperature decreases, the superconducting anisotropy $\gamma\sim 4$ of PrFeAsO$_{1-\delta}$ increases near $T_c$ and tends to decrease slightly at lower temperatures.