Superconductivity in Y-Ba-Cu-O systems

Abstract
A superconducting transition with an onset temperature higher than 80 K has been found in Y-Ba-Cu-O systems. Y2.4Ba3.6Cu6O14- delta shows a weak Meissner effect whereas in YBa2Cu3O8- delta the Meissner signal is 10% of the complete diamagnetism. For the latter system the critical fields have been determined from magnetisation measurements and are reported here.