Preparation of high-performance high temperature superconducting Bi-2212 wires by the spray pyrolysis powder

Yang, Bo; Hao, Qingbin; Xiao, Peng; Liu, Guoqing; Jiao, Gaofeng; Yao, Kai; Xu, Xiaoyan; Cui, Lijun; Zhang, Shengnan; Li, Chengshan; Feng, Jianqing

doi:10.1007/s10854-023-11072-8

Cited by 2 publications

(1 citation statement)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To achieve its best performance, Bi-2212 wire has to undergo an overpressure heat treatment (OPHT) with multiple steps and multiple parameters, which affect both the microstructure and transport critical current density (J c ) [1,8,9]. It was recently showed that the quality of the precursor powder has a significant effect on the wire performance and on the narrow processing window on Bi-2212 [10,11]. An important factor in understanding J c defined by I c /A fil is that in unreacted wires the filaments are not fully dense, with the powders typically occupying 2/3 of the filament cross-section and the balance being trapped gas, typically air.…”

Section: Introductionmentioning

confidence: 99%

Variation of effective filament diameter, irreversibility field, anisotropy, and pinning efficiency in Bi-2212 round wires

Tarantini,

Barua,

Oloye

et al. 2023

Supercond. Sci. Technol.

View full text Add to dashboard Cite

In recent years Bi2Sr2CaCu2O x (Bi-2212) received increasing attention due to its round wire multifilamentary architecture, a unique feature in high-Tc superconductor. In fact, round wires are preferable for magnet designs, including solenoids for nuclear magnetic resonance (NMR) or research purpose and accelerator magnets. However, due to the narrow over-pressure heat treatment conditions necessary to obtain high Jc and to the peculiar microstructure of Bi-2212 wires, a full understanding of the correlations between the different properties has not yet been developed. In this paper we investigate the effect of a vital part of Bi-2212 optimization, the maximum heat-treatment temperature T max in the range of 885 °C–896 °C, on the variations of Jc , effective filament diameter d eff, anisotropy γ, INTER- and intra-grain irreversibility fields and pinning energies U 0, all critical parameters in unravelling the complex mix of vortex pinning and connectivity that ultimately determines the critical current density. We found that d eff of the higher Jc wires heat-treated at lower temperature is much smaller than for the lower Jc wires. Moreover, a systematic increase of the irreversibility field and a decrease of the intrinsic Bi-2212 anisotropy underpins the higher Jc . The analysis of the pinning energies reveals that there is little sample-to-sample variation in the INTER-grain pinning, whereas in all samples the intra-grain pinning has an enhancement below ∼40–45 K becoming more and more evident with increasing Jc . These results suggest that the overall Jc performance are not only related to the wire microstructure and connectivity, which obviously affect the INTER-grain properties, but they are also intimately related to the intrinsic and intra-grain properties such as γ and U 0.

show abstract