TUNNELING MEASUREMENTS ON A BISRCUO SINGLE-CRYSTAL UP TO THE CRITICAL MAGNETIC-FIELD

The tunneling to superconducting BiSrCuO (critical temperature T(c) = 10 K) has been studied in an applied magnetic field up to 10 T. At 0.7 T a pronounced change has been observed in the tunneling conductance: the gap-like structure of the Nb counter electrode disappears, while the bias-voltage position of the second one diminishes by an amount of the Nb gap. At higher fields the gap-like peak of BiSrCuO is smeared out and shifts to lower bias-voltages linearly with the pair-breaking field.