Conductivity and microwave response of YBaCuO Josephson junctions on YSZ bicrystal substrate

We have studied conductivity and microwave response of single YBaCuO Josephson junctions (JJ) and their one-dimensional serial arrays. The I-V characteristics, conductivity, differential resistance and detector response of microwave radiation with frequencies F=134 and 550 GHz were measured in the temperature range from 4.2 to 88 K. Total conductivity of YBaCuO JJ was in general determined by the RSJ model with deviations affected by the influence of localized states forming around a bicrystal boundary. Microwave response of YBaCuO JJ contains two components: the Josephson component that predominates at low bias voltage, and observed at high bias voltage component due to the microwave-induced increase of the probability of inelastic resonant quasiparticle tunneling through several localized states, where response voltage changes its sign.