Crystal growth of Bi-2(Sr,Nd/Sm)(2)CuOy and their superconductivity

Bi(2)Sr(2-x)Ln(x)CuO(y) (Ln = Nd, Sm) was synthesized in the range of x = 0 .2-0.6 and a single phase was obtained in the range of x = 0.3-0.6. A diama gnetic signal was observed for x = 0.2-0.6 and the maximum T-c of 23 K for Nd3+ and 17 K for Sm3+ was obtained around x = 0.5 and 0.4, respectively. S ingle crystals of Bi(2)Sr(2-x)Ln(x)CuO(y) (Ln =Nd, Sm) were successfully gr own by the self-flux method from the melt of stoichiometric composition. DT A was used to determine the thermal cycle. The as-grown crystal from the me lt of Bi2Sr1.6CuOy was Bi1.8Sr1.1Nd0.7CuOy with dimensions over 2mm and exh ibited superconductivity at T-c similar to 20K. The crystal growth of Bi2Sr 2-xSmx,CuOy was examined for the stoichiometric melt of Bi2Sr1.5Sm0.5CuOy H owever, we could not observe single crystal with 2 2 0 1 structure. The cry stal had 2 2 1 2 structure and showed no superconductivity. (C) 2001 Elsevi er Science B.V. All rights reserved.