Observation of the Josephson Effect in Y-Ba-Cu-O Compound

Abstract

This letter describes a weak-link Josephson junction with critical current of 10 mA and normal resistance of 0.02 Ω. The junction was fabricated from a rod of Y₁Ba₂Cu₃O _x compound. The rod was bonded to a ceramic substrate, for mechanical stability, and a diamond-edged cutting wheel was used to cut a narrow slot in the rod, leaving a small land where the two “islands” of rod are connected. The junction can with-stand thermal cycling between room temperature and 77 K. The AC Josephson effect was observed at 77 K, the temperature of liquid nitrogen, when X-band microwave radiation was applied.