CRYSTAL-GROWTH AND CHARACTERIZATION OF RE-SUBSTITUTED BI-SR-CA-CU-O SUPERCONDUCTORS (RE=Y, ER, YB)

Crystals of RE-substituted Bi-Sr-Ca-Cu-O (2212) superconductors (RE = Y, Er, Yb) were grown by a modified self-flux growth technique. A two-stage process with preliminary melt quenching was used to prepare well-defined platelet crystals with thicknesses of up to 5-20 mum. The mechanism of crystallization in sealed cavities is considered. The RE-substituted crystals show a decrease of T(c) with increase of RE content in crystals up to the loss of superconducting properties at a complete substitution Ca --> RE(Y). The superconducting properties of Bi2Sr2Ga1-xRExCu2Oy crystals are improved after air annealing at 750-degrees-C.