Resistivity Anomaly Near Room Temperature of Y-Ba-Cu-O and Related Oxides as Created by the Surface Effect of Water

A number of papers have recently reported the possible presence of superconductivity near room temperature in Y-Ba-Cu-O oxide and related materials, based mainly on resistivity measurements. Close examinations of the electrode contacts during resistivity measurements in the present study showed that similar resistivity anomalies could be reproducibly observed when the specimen surface was wet. The anomaly turned out to be related with artifacts of the electrode contacts which resulted from the reaction of the specimen surface with water, creating electrochemical current paths between the electrodes.