中文摘要：

本文采用顶部籽晶熔融织构法（TSMTG）成功地将纳米Y2Ba4CuBiOx（YBi2411）引入了YBCO超导块材，研究了YBi2411掺杂量对单畴YBCO超导块材晶体生长形貌和磁悬浮力的影响．结果表明，YBi2411在YBCO超导块材中呈现出直径约100nm-200nm的纳米点状粒子和直径约100nm-200nm，长约2μm的纳米棒状粒子．当YBi2411添加量x≤8wt％时，样品均可长成完整的单畴YBCO超导块材，样品的磁悬浮力随着YBi2411掺杂量的增加而增大；当x≥8wt％时，样品均可长成一定的单畴区，但随着YBi2411掺杂量的增加，YBCO超导块材的单畴区域逐渐减小，且随机成核现象越来越严重，同时磁悬浮力逐渐减小；当x=8wt％时，样品磁悬浮力最大．在此基础上，结合超导材料的微观形貌，分析了YBi2411掺杂量对单畴YBCO超导块材磁悬浮力的影响．

英文摘要：

Single-domain YBCO superconducting bulks with different Y2Ba4CuBiOx （YBi2411） content have been fabricated by top seeded melt-textured growth（TSMTG） process, and the effect of YBi2411 doping content on the levitation force was investigated. It is found that namometer YBi2411 particles （Ф100 nm-200 nm） and nanometer YBi2411 rods （Ф100 nm-200 nm, 2μm in length） have been introduced into single-domain YBCO bulks by TSMTG process; single-domain up to the whole size of the YBCO bulks can be fabricated when YBi2411 addition x ≤ 8 wt%, the density of YBi2411 nano-particles and nano-rods is increasing with the increases of YBi2411 addition, which results in the increasing of the levitation force because of the enhancement of the flux pinning center in the samples. When x ≥ 8wt%, the single domain area is reduced and random nucleations are difficult to be depressed, so the levitation force is decreasing with the increases of YBi2411 addition because reduction of the superconducting volume in the samples. The largest levitation force of the sample can be obtained with x = 8 wt%, because there is a reasonable ration among the superconducting phase, Y211 and YBi2411 phases.