Annealing effects on superconductivity in SrFe2-xNixAs2

TL;DR

This study investigates how Ni doping and annealing affect superconductivity in SrFe2-xNixAs2, revealing optimal doping levels and significant Tc enhancement through heat treatment.

Contribution

It demonstrates that annealing can substantially increase the superconducting transition temperature in Ni-doped SrFe2As2.

Findings

Superconductivity appears near x=0.15 with Tc ~9.8 K.

Annealing enhances Tc by approximately 50%.

Antiferromagnetic order is suppressed with Ni doping.

Abstract

Superconductivity has been explored in single crystals of the Ni-doped FeAs-compound SrFe2-xNixAs2 grown by self-flux solution method. The antiferromagnetic order associated with the magnetostructural transition of the parent compound SrFe2As2 is gradually suppressed with increasing Ni concentration x and bulk-phase superconductivity with full diamagnetic screening is induced near the optimal doping of x = 0.15 with a maximum transition temperature Tc ~9.8 K. An investigation of high-temperature annealing on as-grown samples indicate that the heat treatment can enhance Tc as much as ~50 %.