Improving Superconducting Performance of Fe(Se, Te) with In Situ Formed Grain-Boundary Strengthening and Flux Pinning Centers
Jixing Liu, Botao Shao, Xueqian Liu, Meng Li, Lina Sang, Wen Zhang, Shengnan Zhang, Jianqing Feng, Chengshan Li, Shi Xue Dou, Jian‐Feng Li, Pingxiang Zhang, Lian Zhou, Xiaolin Wang
Abstract
It is well known that the existence of interstitial Fe is a great obstacle to enhancing the superconducting properties of the Fe(Se, Te) system. In this work, a silver and oxygen codoping effect toward enhancement of the superconductivity and flux pinning in Fe(Se, Te) bulks is reported. The oxygen ions from SeO2 can induce the precipitation of interstitial Fe as Fe2O3, thus simultaneously optimizing the superconducting properties of Fe(Se, Te) and forming extra flux pinning centers, while the existence of Ag can enhance the intergrain connections of the polycrystalline material by improving the electron transport at grain boundaries. Compared with the undoped sample, the critical current density, the upper critical field, and the thermally activated flux flow activation energy are greatly enhanced by 4.7, 1.7, and 1.5 times, respectively. The novel synthesis technique and optimized properties of this work can pave the way for the development of high-performance Fe(Se, Te) superconducting wires or tapes.