SELF-PUMPING MIXING PHENOMENON IN YBCO JOSEPHSON-JUNCTION

This paper describes a Josephson self-pumping mixing experiment using YBCO step-edge Josephson junctions at 4.2 K. We used blackbody noise s ource as a signal, and the IF output was measured as a function of the junction bias voltage. The IF output showed two main peaks which corr espond to an array of two grain boundary junctions. We obtained a 0.4 dB increase of the IF output by changing the 77 K blackbody to 300 K b lackbody at 10 mu V, and the noise temperature was estimated to be abo ut 2000 K.