Dynamical properties of Josephson vortices in mesoscopic intrinsic Josephson junctions in single crystalline Bi2Sr2CaCu2O8+δ

Dynamical nature of Josephson vortices confined within a micron sized mesoscopic intrinsic Josephson junction made of single crystalline Bi2Sr2CaCu2O8+δ has been investigated by dc-resistivity and I–V characteristics measurements of the junction. Two types of periodic oscillations of the dc-resistivity of the junction as a function of applied magnetic field H has been confirmed as observed previously, but interpreted differently, i.e., by the two purely quantum mechanical effects: one is the interference effect which gives a period of H0 = ϕ0/sL and the other is the diffraction effect which gives the same frequency of ϕ0/sL but phase shifted by ϕ0/2sL, where s is the interlayer distance, L the width of the junction perpendicular to the magnetic field and ϕ0 the quantum magnetic flux. The characteristic features of the oscillation are summarized based on the experimental findings. At higher currents, where such an oscillating behavior diminishes, we succeeded in directly observing electromagnetic radiation emitted from the intrinsic Josephson junction system towards outgoing direction of the vortices from the sample. The integrated power detected by the bolometric detector is estimated to be of the order of 100 W/cm2. The condition for radiation is discussed.