Superconductivity in the Iron-Pnictide Parent Compound SrFe2As2

TL;DR

This study investigates the emergence of superconductivity in undoped SrFe2As2, revealing its sensitivity to heat treatment and mechanical deformation, and providing insights into its phase behavior at ambient pressure.

Contribution

It demonstrates that superconductivity in SrFe2As2 can be induced and manipulated through mechanical deformation and annealing, offering new understanding of its phase properties.

Findings

Superconductivity appears below 21 K with up to 15% volume fraction.

Heat treatment suppresses superconductivity, while cold-working reinstates it.

Superconductivity in SrFe2As2 is sensitive to mechanical and thermal processing.

Abstract

The appearance of superconductivity at ambient pressures in the undoped iron pnictide parent compound SrFe2As2 is studied experimentally using several techniques and approaches to aid in understanding the nature of this phase. Low temperature magnetization measurements of single crystals of SrFe2As2 reveal diamagnetic screening due to the onset of superconductivity below 21 K, with volume fraction estimates varying between 0 and 15 percent. The effects of heat treatment and cold-working via severe mechanical deformation on the superconducting phase found are studied, showing that superconductivity can be suppressed via modest annealing and reinstated by cold-working.