Low-noise 115-GHz mixing in superconducting oxide-barrier tunnel junctions

Abstract

Small-area (≲1 μm2) oxide-barrier tunnel junctions have been made of thermally cyclable superconducting Pb alloys for use as high-frequency mixers. A single-sideband mixer noise temperature of <100 K has been achieved at 115 GHz. This result was achieved in the quasiparticle (classical) mixing mode.