Origin and elimination of excess iron particles in off-stoichiometric Ba0.6K0.5-βFe2As2+8 superconductors

被引：11

作者：

Tu, Chang ^{[1
,2
]}

Dong, Chiheng ^{[1
,2
,3
]}

Fu, Caida ^{[1
,2
]}

Han, Meng ^{[1
,2
]}

Tang, MingHui ^{[1
,2
]}

Huang, He ^{[1
,2
]}

Yao, Chao ^{[1
,2
,3
]}

Wang, Dongliang ^{[1
,2
,3
]}

Zhang, Xianping ^{[1
,2
,3
]}

Ma, Yanwei ^{[1
,2
,3
]}

机构：

[1] Chinese Acad Sci, Inst Elect Engn, Key Lab Appl Superconduct, Beijing 100190, Peoples R China

[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

[3] Inst Elect Engn & Adv Electromagnet Drive Technol, Jinan 250013, Peoples R China

来源：

SCRIPTA MATERIALIA | 2023年 / 235卷

基金：

中国国家自然科学基金;

关键词：

Iron -based superconductors; Ferromagnetic impurities; Reaction mechanism; CRITICAL-CURRENT DENSITY;

D O I：

10.1016/j.scriptamat.2023.115595

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Iron impurities frequently observed in BaxK1-xFe2As2 wires and tapes not only cause local suppression of su-perconductivity but also act as macro-obstacles to transport current. We find that the agglomerated iron particles are not introduced by external sources or caused by incomplete reactions but result from the chemical envi-ronments determined by nominal compositions. The excess K added to the raw materials for compensating the evaporated K consumes the stoichiometric arsenic and induces unreacted iron. Decreasing the K content indeed removes the redundant Fe but also deteriorates superconductivity. Instead, slightly excessive addition of As is proved to be a twin-track approach in fabricating high-performance superconductors. Through modulation of the nominal composition Ba0.6K0.5-& beta;Fe2As2+8, we effectively eliminate the iron impurities and improve the transport critical current density of the tape to Jc(4.2 K, 10 T)=9.59x104 A/cm2. A reaction model is proposed to explain the formation mechanism of the iron particles.

引用

页数：6

共 36 条

[1] Enhanced critical current density in Gd-added (Bi, Pb)-2212 bulk superconductor [J].