Superconductivity and magnetism in platinum-substituted SrFe2As2 single crystals

TL;DR

This study explores how platinum substitution in SrFe2As2 influences its magnetic and superconducting properties, revealing a broad superconducting range with a maximum Tc of 16 K, and suggesting complex underlying mechanisms.

Contribution

It provides the first detailed phase diagram of SrFe2-xPtxAs2, showing extended superconductivity and higher Tc compared to similar substitutions, indicating complex effects beyond electron counting.

Findings

Superconductivity appears for 0.08 < x < 0.36 with Tc up to 16 K.

Pt substitution suppresses magnetic/structural transition.

Phase diagram resembles other group VIII element substitutions but with enhanced Tc.

Abstract

Single crystals of SrFe2-xPtxAs2 (0 < x < 0.36) were grown using the self flux solution method and characterized using x-ray crystallography, electrical transport, magnetic susceptibility, and specific heat measurements. The magnetic/structural transition is suppressed with increasing Pt concentration, with superconductivity seen over the range 0.08 < x < 0.36 with a maximum transition temperature Tc of 16 K at x = 0.16. The shape of the phase diagram and the changes to the lattice parameters are similar to the effects of other group VIII elements Ni and Pd, however the higher transition temperature and extended range of superconductivity suggest some complexity beyond the simple electron counting picture that has been discussed thus far.