Author:
Wang Yanan,Zhang Zerong,Gao Zhan,Wang Lei,Wang Qiuliang
Abstract
AbstractREBCO has been used extensively as coated conductors applied to superconducting magnets due to its exceptional superconducting properties. As a REBCO superconductor, YbBa2Cu3O7−y (Yb123) has a low melting temperature, making it suitable for use as an intermediate medium connector while preparing the superconducting joint. However, there is still uncertainty about the formation mechanism of Yb123 and the synthesis of this superconductor has not been fully understood. Therefore, this study systematically investigated the phase transformation process of Yb123 during heat treatment in flowing oxygen. The results indicated that Yb123 sample with the highest phase purity could be obtained by annealing at 927 °C or 937 °C but not in between, respectively. Furthermore, a quantitative phase analysis revealed that the sample annealed at 937 °C had a phase purity greater than 80 wt%. Additionally, a strong c-axis texture was observed in the bulk Yb123 superconductor prepared at 937 °C. Meanwhile, the superconducting results revealed that the bulk sample’s Tc was 89.9 K, and its self-field critical current densities at 4.2 K and 77 K were 1.3 × 105 A/cm2 and 5.0 × 103 A/cm2, respectively. Based on the results mentioned above, the phase transformation process and formation mechanism of Yb123 in flowing oxygen were elaborated.
Funder
the Research Project of Ganjiang Innovation Academy, CAS
the research fund of Key Laboratory of Rare Earth, Chinese Academy of Sciences
National Key Research and Development Program of China
National Natural Science Foundation of China
Young Innovation Promotion Association, CAS
Beijing Nova Program
the Institute of Electrical Engineering, CAS
Publisher
Springer Science and Business Media LLC