The observation of subharmonic peculiarities of I-V characteristic of edge-type Josephson junction chains placed in microwave resonator

The spectrums of own Josephson radiation and I-V characteristics of one-dimensional chains of edge-type Nb Josephson junction placed into microwave resonator have been studied. The interaction with the external resonator caused synchronization of junctions forming the chain. This effect was detected experimentally. In the hysteresis region of I-V characteristic we have found the presence of own radiation area. Its bounds are determined by the value of junction characteristic voltage and are practically independent from the value of chain bias voltage. The studies of negative differential resistance region of I-V characteristic shows the presence of thin structure which may be interpreted as a set of subharmonic steps caused by the coupling of Josephson junction own radiation with external microwave resonator.