Anomalous Resistive Behavior in Er 1 Ba 2 Cu 3 O 9-δ at 2290 K

Interest in high Tc superconductivity has increased on a par with the reports of higher transition temperatures. These reports range from Tc’s near 30 K in the La-Ba-Cu-O system [1], to 90 K in the Y-Ba-Cu-O system [2] and rare earth substituted compounds of the form R1 Ba2Cu3O9-δ where R = Nd, Sm, Eu, Gd, Ho, Er, and Lu. [3–5] Recently an indication of superconductivity was observed at 240 K in Y1Ba2Cu3O9-δ by the reverse AC Josephson effect, [6] and zero resistances as high as 155 K were reported in the system Y1Ba2Cu3O9-δ :F. [7]