The effect of excess barium oxide addition on the properties of Nd1Ba2Cu3Oy by the melt-growth process

The effects of excess BaO additions on the properties of NdBCO snperconduct ors have been investigated. It is found that the onset T-c (T-con) of the N dBCO samples (Nd1Ba2Cu3Oy + xBaO) with differential excess BaO additions (x = 0, 0.2, 0.4, 0.6) are very complicated. It is difficult to conclude that excess BaO addition can depress the substitution degree of Nd atoms on Ba sites and improve the T-con of the NdBCO superconductors by the melt-growth process in air. A new method (Ba-rich melt growth or BaRMG) has been devel oped for the preparation of small-size (in millimeter order) NdBCO single c rystal in small scales. The crystals are suitable to be used as seeds for t he preparation of large single-domain YBCO bulk superconductors. (C) 2000 E lsevier Science B.V. All rights reserved.