Improvement of superconducting properties of FeSe0.5Te0.5 single crystals by Mn substitution

TL;DR

This study demonstrates that 2% Mn substitution in FeSe0.5Te0.5 single crystals enhances superconducting properties, including higher transition temperature, increased critical field, and larger superconducting gap, indicating improved superconductivity due to doping.

Contribution

The paper provides new insights into how Mn doping improves the superconducting characteristics of FeSe0.5Te0.5 single crystals, with detailed structural and electronic property analysis.

Findings

Higher onset temperature and narrower transition width in Mn-doped samples

Increased upper critical field Hc2 of ~580 kOe for doped samples

Larger superconducting gap Delta(0) of 31 K in Mn-doped samples

Abstract

We report on structural, susceptibility, conductivity, and heat-capacity studies of FeSe0.5Te0.5 single crystals with 2% substitution of Mn for Fe. Mn-doped samples show a higher onset temperature, a narrower width of the superconducting transition, and a higher magnitude of the jump in the specific heat at Tc in compared to undoped samples. From the resistivity data in magnetic fields parallel to the c axis we derived an upper critical field Hc2 of ~580 kOe for doped samples compared to 490 kOe for pure samples. Using a single-band BCS model we can describe the electronic specific heat in the superconducting state with a gap Delta(T=0) = 31 K for the Mn doped sample in comparison to 26 K for pure FeSe0.5Te0.5.