Superconductivity suppression of Ba0.5K0.5Fe2-2xM2xAs2 single crystals by substitution of transition-metal (M = Mn, Ru, Co, Ni, Cu, and Zn)

TL;DR

This study examines how magnetic and nonmagnetic impurities affect superconductivity in Ba0.5K0.5Fe2-2xM2xAs2 single crystals, revealing that impurity effects are weaker than expected and are likely due to localization rather than pair-breaking.

Contribution

It provides new insights into impurity effects on superconductivity in iron-based superconductors, highlighting the role of localization over pair-breaking in Tc suppression.

Findings

Superconductivity is robust against Ru impurities.

Weak Tc suppression from Mn, Co, Ni, Cu, and Zn impurities.

Localization effects dominate at high impurity levels.

Abstract

We investigated the doping effects of magnetic and nonmagnetic impurities on the single-crystalline p-type Ba0.5K0.5Fe2-2xM2xAs2 (M = Mn, Ru, Co, Ni, Cu and Zn) superconductors. The superconductivity indicates robustly against impurity of Ru, while weakly against the impurities of Mn, Co, Ni, Cu, and Zn. However, the present Tc suppression rate of both magnetic and nonmagnetic impurities remains much lower than what was expected for the s\pm-wave model. The temperature dependence of resistivity data is observed an obvious low-T upturn for the crystals doped with high-level impurity, which is due to the occurrence of localization. Thus, the relatively weak Tc suppression effect from Mn, Co, Ni, Cu, and Zn are considered as a result of localization rather than pair-breaking effect in s\pm-wave model.