AG2O-DOPED BI2SR2CA1CU2OX SUPERCONDUCTORS PREPARED VIA MELT-QUENCHING

Ag2O-doped superconducting Bi2Sr2Ca1Cu2Ox ceramics were prepared by a melt-quenching-reheating method. It is found that the Ag2O-doped, as-c ast specimens exhibit superconductivity (T(c) = around 80 K) by heat t reatment at temperatures around 800-degrees-C even in an evacuated and sealed silica glass tube, while the undoped specimens do not and vapo rize by the corresponding heat treatment. Conversion of the Ag2O-doped , as-cast specimens into superconducting ceramics when heated in an ev acuated vessel is explained in terms of the oxygen donor of Ag2O in th e specimen. This finding enables us to fabricate a desired shape of su perconducting Bi2Sr2Ca1Cu2Ox ceramics sealed in metals or glasses. The addition of Ag2O to Bi2Sr2Ca1Cu2Ox melt, however, had deleterious inf luences on the superconducting properties (T(c) and J(c)) of the resul tant ceramics when obtained by heat treatment in air.