Tetsuro Sato

Energy Gap Measurement Made on “Clean” and Oriented YBa2Cu3O7-δ Surfaces

Superconductive energy gap of YBa2Cu3O7-δ is measured in a novel broken film edge junction. (001), (103) and (110) oriented films are broken in a cryogenic environment along the appropriate directions together with the SrTiO3 substrate. Pb electrode is brought close in situ to the clean broken film edge. The normalized energy gap 2Δ(0)/kBTc measured in the direction along and perpendicular to the Cu-O plane are found to be 5.9±0.2 and 3.6±0.2 respectively. These values are independent of the variation in the values of Tc within the examined range of 40K~90K. The gap difference structure at ΔYBCO-Δpb is observed which help identifying the value of energy gap of the oxide superconductor unambiguously. Identification of the gap energies in BiSrCaCuO system by the same technique was attempted.