Hydrothermal synthesis of superconductors Ba1-xKxBiO3 and double perovskites Ba1-xKxBi1-yNayO3

Superconductors Ba1-xKxBiO3 and body-centered double perovskites Ba1-xKxBi1-yNayO3 have been selectively synthesized by a facile hydrothermal route. The appropriate ratio and adding sequence of initial reagents, alkalinity, reaction temperature and time are the critical factors that influence the crystal growth of the compounds. The purity and homogeneity of the crystals were detected by the ICP, SEM, EDX and TEM studies. Magnetic measurements show that the superconducting transition temperatures TC of Ba1-xKxBiO3 decrease from 22 K (for x = 0.35) to 8 K (for x = 0.55) with increasing the K doping level. (C) 2011 Elsevier B.V. All rights reserved.