Synthesis and Characterization of Cuprate Superconductors from Solutions in Liquid Ammonia
YBa2Cu3O7−x (123) superconducting powders have been advantageously prepared from liquid ammonia solutions of nitrate, acetate, and perchlorate precursors. The synthetic techniques used include solution pyrolysis, freeze drying, and chemical solidification by reaction with a Lewis acid. Metal stoichiometry was determined by gravimetric analysis and atomic absorption spectroscopy. Phase characterization was accomplished by powder X-ray diffraction which revealed at least 98% pure 123 for some samples. Resistivity and magnetic susceptibility measurements confirm the superconducting properties of the products with critical temperatures around 90 K. Finally, chemical and superconducting properties are discussed as a function of process parameters.
Schaeffer, Richard W.; Macho, J.; and Salomon, R.E., "Synthesis and Characterization of Cuprate Superconductors from Solutions in Liquid Ammonia" (1991). Educator Scholarship. 49.