Excitation of Josephson plasma by Josephson vortex flow

We have performed current-voltage (I-V) measurements on intrinsic Josephson junctions of Bi2Sr2CaCu2O8+delta single crystals to study the excitation o f a Josephson plasma by a Josephson vortex flow. Junctions have been fabric ated by using a focused ion beam in the in-line symmetric structure. In the I-V characteristics under magnetic field parallel to the Cu-O layers, an e nhancement of the Josephson current at constant voltage was observed on the vortex flow branches in the narrow range of magnetic field between 5 to 9 kOe. Although no signals in the detection limit of the detectors was observ ed, it is suggested that the enhancement of the current might be a sign of the emission of Josephson plasma. It is also pointed out that problems are in emitting the electromagnetic wave to free space from the junction. (C) 2 001 Elsevier Science B.V. All rights reserved.