Synthesis of Bi2Sr2CaCu2O8+δ whiskers without oxygen stream

A synthesis technique of Bi2Sr2CaCu2O8+delta single-crystal whiskers was studied. The whiskers were synthesized by heating glassy melt-quenched Bi-Sr-Ca-Cu-O (3:2:2:4 in cationic ratio) plates. The atmospheric condition of the whisker growth, especially oxygen partial pressure and gas flown was investigated. It was found out that the whisker growth rate shows a maximum at P-O 2 = 2/3 bar. For the crystalline quality of the whiskers, the airtight condition was found to be useful as compared to the conventional oxygen stream condition. The crystalline quality, especially the straightness and morphology of the surface, could be improved by keeping the growing whiskers under the equilibrium P-Bi condition. Over 20-mm-long whisker crystals have been successfully synthesized by choosing the optimum oxygen partial pressure around P-O 2 = 2/3 bar in the airtight condition. (C) 2001 Elsevier Science B.V. All rights reserved.