The effect of excess barium oxide addition on the properties of Nd 1Ba 2Cu 3O y by the melt-growth process

Abstract

The effects of excess BaO additions on the properties of NdBCO superconductors have been investigated. It is found that the onset T c ( T con) of the NdBCO samples (Nd 1Ba 2Cu 3O y + 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 developed for the preparation of small-size (in millimeter order) NdBCO single crystal in small scales. The crystals are suitable to be used as seeds for the preparation of large single-domain YBCO bulk superconductors.