CONDUCTANCE CHARACTERISTICS OF BISRCACUO-BASED TRILAYER STRUCTURES

Tunneling spectroscopy has been performed on Cu2O8+delta/Bi2Sr2YCu2O8delta/Bi2Sr2CaCu2O8+delta trilayers deposited with a DC sputtering sys tem in pure oxygen plasma. The conductance curves show either flat or linear increasing backgrounds, on which gap-like features are superimp osed. The observation of the superconducting structures is consistent with the opening of the energy gap observed at the Bi2Sr2CaCu2O8+delta T-c in the zero-bias conductance measurements as a function of temper ature. Zero-bias anomalies are also present in the tunneling spectra. These have been commented in the framework of the Appelbaum theory, as well as with respect to a possible d-wave symmetry of the order param eter. (C) 1998 Elsevier Science B.V.