Properties of YBa2Cu3O7−x/YBa2Cu2.79Co0.21O7−x/YBa2 Cu3O7−x edge junctions

Abstract
We report the properties of YBa2Cu3O7−x/YBa2Cu2.79Co0.21O7−x/YBa2 Cu3O7−x junctions in an edge junction geometry as a function of temperature and barrier thickness. The barrier material used in this work, YBa2Cu2.79Co0.21O7−x, is an underdoped version of YBa2Cu3O7−x, which has a lower carrier density, a lower Tc, and a higher anisotropy than YBa2Cu3O7−x. The resistances of the junctions are proportional to the thicknesses of their barriers, suggesting the presence of very little interface resistance. The temperature dependences of critical currents and junction resistances show behavior consistent with that predicted by the conventional proximity effect.