Relaxation Oscillator Using Nb/AlOx/Al/Nb Josephson Junctions Measured with DC Superconducting Quantum Interference Devices

In this paper we propose a new measurement method to investigate the basic properties of a Josephson relaxation oscillator (RO) using dc superconducting quantum interference devices (SQUIDs). The dc SQUIDs linearly and continuously convert the oscillating current into voltage enabling the waveforms to be clearly observed. The voltage and current waveforms have been measured simultaneously. The basic operation of the RO has been experimentally confirmed.