Hysteretic, high T c Josephson junctions using heterostructure trilayer films grown by molecular beam epitaxy

Abstract
Hysteretic Josephson junctions have been fabricated by growing c‐axis oriented trilayer Bi2Sr2CaCu2O8/Bi2Sr2(Ca,Bi, Sr)7Cu8O20/Bi2Sr2CaCu2O8 single‐crystal thin films and patterning them into devices. To our knowledge, these are the first cuprate superconductor junctions to exhibit current‐voltage characteristics with substantial hysteresis. Current flow in the devices is in the vertical (c axis) direction, through an ultrathin (∼30 Å) barrier layer. The current‐voltage response shows large, sharp Shapiro steps under microwave illumination.