Superconductivity at high Tc in neodymium-doped 1111-SrFeAsF system

TL;DR

This study reports high-temperature superconductivity up to 52 K in Nd-doped SrFeAsF, revealing coexistence with magnetic order and identifying the doping level critical for superconductivity onset.

Contribution

It demonstrates the emergence of superconductivity at high Tc in Nd-doped SrFeAsF and explores the interplay between magnetic order and superconductivity.

Findings

Superconductivity appears above 0.40 Nd-doping with Tc up to 52 K.

Magnetic ordering coexists with superconductivity at certain doping levels.

The spin-density-wave anomaly persists up to 0.35 Nd-doping.

Abstract

Polycrystalline Sr1-xNdxFeAsF samples were prepared at various Nd-doping levels using both a stoichiometric mixture of the starting materials and in slight excess amounts of FeAs. Susceptibility and resistivity of the samples were studied down to 4 K revealing a probable coexistence of superconductivity and a magnetic ordering. Temperature dependence of resistivity for all the Nd-doped samples shows the presence of a transition below 15 K most likely originating from the magnetic ordering of Nd moments, while the spin-density-wave anomaly at 175 K survives up to 0.35 Nd-doping. Superconductivity only occurs above 0.40 Nd-doping with onset maximum Tc reaching as high as 52 K.