Superconductivity in the iron-pnictide parent compound SrFe2As2

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%. 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.