124 K SUPERCONDUCTIVITY IN Cu-Ba-Ca-Cu-O

A superconducting phase with a transition temperature up to 124 K has been detected in multiphase samples of Cu-Ba-Ca-Cu-O synthesized under pressures between 5.5 and 6 GPa and at temperatures between 820 and 870 degrees C. The 124 K transition is attributed to a phase closely related to CuBa2Can-1CunOy, which is known to be superconducting only below 117 K, with a possible subtle change in the local atomic arrangement or stoichiometry. Structure details and the optimal synthesis conditions of the 124 K phase have yet to be determined.