Bi-2(Sr, Ln)(2)CuOz (Ln = Nd, Sm) phases: stability, crystal growth and superconducting properties

Bi-2(Sr, Ln)(2)CuOz (Ln = Nd, Sm) single crystals were successfully grown b y a self-Flux method from stoichiometric and (Bi, Cu)-rich melts. Thermal a nalysis and thermogravimetry were used to determine stability and the melti ng sequence of Bi-2(Sr, Ln)(2)CuOz phases in air. As-grown crystals of the ideal Bi-2(Sr, Ln)(2)CuO2 phase, of dimensions 1 x 0.5 x 0.03 mm(3), exhibi t superconducting behaviour with critical temperature T-c = 21 K for the Bi 1.9Sr1.6Nd0.6CuOz crystal and T-c = 14 K for the Bi1.8ST1.6Sm0.6CuOz crysta l. The compositions of these crystals were homogeneous and close to the sto ichiometric composition. We report on the growth of Bi2Sr2-xSmxCuOz single crystals of large dimensions 9 x 3 x 0.03 mm(3) using Bi2Sr1.5Sm0.5CuOz as precursor and Bi2CuO4 as flux.