Striking Zn impurity effect on the Fe-based superconductor BaFe1.87Co0.13As2

TL;DR

This study investigates how nonmagnetic Zn impurities suppress superconductivity in the n-type Fe-based superconductor BaFe1.87Co0.13As2, revealing a linear decrease in Tc with impurity concentration and confirming its fragility.

Contribution

First experimental confirmation of the fragile nature of superconductivity against nonmagnetic impurities in n-type 122 Fe-based superconductors.

Findings

Tc decreases linearly with Zn concentration

Superconductivity disappears at 7 at.% Zn

Results differ from p-type Ba0.5K0.5Fe2As2 studies

Abstract

Nonmagnetic impurity effect was studied on the n-type Fe-based superconductor BaFe1.87Co0.13As2 (Tc = 25 K) by a successful Zn substitution for Fe up to 7 at.%. Magnetic susceptibility, electrical resistivity, specific heat, and Hall coefficient measurements indicated that Tc linearly decreases with the Zn concentration and disappears at 7 at.%. The result is quantitatively comparable with what was observed for YBCO, while it disagrees with a recent report for the p-type Ba0.5K0.5Fe2As2. Fragile SC against a nonmagnetic impurity was first confirmed for the n-type 122 Fe-based superconductor.