Stray-Field Effects In Submicron Yba2cu3o7-X Bicrystal Grain Boundary Junctions

We have investigated the magnetic field dependence of the critical current in submicron YBa2Cu3O7-x [001] tilt bicrystal grain boundary junctions. The good homogeneity of submicron grain boundary barrier interfaces, together with the large magnetic field needed to modulate the Josephson current, allow to observe several features not observed in micron size junctions, like a nonconstant modulation period, strongly dependent on the maximum applied magnetic field. Experimental results are well accounted for by a theoretical model taking into account the magnetization of the nearby electrode, and the strong interaction of its stray field with the junction interface. The analysis of the nature of this interaction and the influence of the device geometry are also relevant for potential applications of high critical temperature LSI devices.