Linear decrease of critical temperature with increasing Zn subsiitution in the iron-based supercunductor BaFe1.89-2xZn2xCo0,11As2.

The nonmagnetic impurity effect is studied on the Fe-based BaFe1.89-2xCo0.11As2 superconductor (Tc = 25 K) with Zn substitution for Fe up to 8 at. %, which is achieved by means of high-pressure and high-temperature heating. Tc decreases almost linearly with increasing Zn content and disappears at ∼8 at. %. It is different in the shared phenomenology of the early Zn doping studies, where Tc decreased little. The decreasing Tc rate, however, remains much lower (3.63 K/%) than what is expected for the s±-wave model, implying the model is inaccurate. Another symmetry model such as the non-sign-reversal s-wave model may better account for the result. [ABSTRACT FROM AUTHOR]