The Preparation and Processing of Bulk Superconducting Ceramic Nd_1.85Ce_0.15CuO_4−y

We report the development of a reaction technique which yields ceramic Nd1.85Ce0.15CuO4−y with macroscopically uniform concentrations of Ce and O. Under appropriate argon annealing conditions, samples exhibiting bulk superconductivity as gauged by resistive transition width and diamagnetic shielding are obtained. In addition, metallic behavior, indicated by positive dρ/dT above Tc, is obtained for the normal state. © 1990, Materials Research Society. All rights reserved.