CRYSTAL-GROWTH AND SUPERCONDUCTIVITY OF (SM0.75CE0.25)(2)SR2CU2NBO10-DELTA

Single crystals of (Sm0.75Ce0.25)(2)Sr2Cu2NbO10-delta (SCSCNO) were gr own by a flux method using SrCu6Oy as flux, and their morphology and s uperconductivity were investigated. We found that the as-grown crystal consists of SCSCNO and SmSr2Cu2NbO8 (SSCNO) crystal layers, with the SCSCNO layer being sandwiched between two non-superconducting SSCNO cr ystal layers. The SSCNO layers can be removed by chemical etching with HCl solution. The SCSCNO crystal shows a superconducting transition a t about 17 K, and the superconducting volume fraction increased when t he crystals were annealed in an oxygen atmosphere. (C) 1998 Elsevier S cience Ltd. All rights reserved.