BiFeO3 nanoparticle doping effect on the growth and properties of Y–Ba–Cu–O superconductors

Abstract

The doping effect of BiFeO3 (BFO) nanoparticles on the growth and properties of Y–Ba–Cu–O (YBCO) superconductors by the powder melt and infiltration growth technique is investigated. The results indicate that nano-BFO doping reduces the growth rate of the Y-123 crystal and finally leads to smaller grain size in the YBCO bulk. Superconducting property measurements prove that improved levitation force and trapped field properties are observed in the 0.2 wt% BFO-doped YBCO sample. Magnetization measurement shows that the YBCO samples exhibit decreased T c values with the increased BFO amount from 0.1 wt%–0.3 wt%, but the transition width ΔT c shows no evident change. The sample with 0.2 wt% BFO addition presents the largest zero-field J c value and also the highest secondary peak value, which accounts for the superior performance of the sample. The electron probe micro analysis results combined with the XRD analysis prove the decomposition of the BFO and formation of the YBi-2411 in the final bulk, while Fe element exists in the form of Fe/Cu substitutions. Thus, the simultaneous introduction and cooperation of the two types of flux pinning centers (i.e. non-superconducting inclusions and element substitutions) can be realized through the addition of nano-BFO.