Effect of high oxygen partial pressure atmosphere for melt-processed YBa2Cu3O6+delta current lead by unidirectional solidification

摘要

Dependence of the crystal growth rate and transport J(c) value on high oxygen partial pressure atmosphere during the solidification process was investigated by taking initial composition of YBa2Cu3O6+x (Y123) + 30 mol% Y2BaCuO5 (Y211) with addition of 0.5 wt.% of Pt on samples processed by different unidirectional solidification rates, namely 1, 3 and 5 mm/h. The traveling rate of the process for obtaining high J(c) current leads can be increased by the conditions with the 100% O-2 atmosphere. The J(c) value of the sample grown with 5 mm/h traveling rate in 100% O-2 atmosphere exhibited as high as that of the sample grown with 3 mm/h traveling rate in air. The values of transport I-c and J(c) of this 1.56 mm phi X 60 mm sample grown at 5 mm/h traveling rate were 1300 A. and 68 000 A/cm(2), respectively, which were obtained by the conventional DC four-probe method with criterion of 1 mu V/cm at 77 K and self-field. (C) 1998 Published by Elsevier Science B.V. All rights reserved. [References: 10]