YBACUO NORMAL METAL YBACUO PROXIMITY EFFECT JUNCTIONS

We have fabricated planar YBaCuO bridge type SNS junctions using a focused ion beam micromachining technique, where N is a classical normal metal such as gold or silver. Although in-situ fabrication is used, high contact resistivities are currently obtained with a nearly flat temperature dependence below the T(c) of the superconductor. A clear effect of the orientation of the f films is seen, and best results are obtained when the current flow is not perpendicular to the CuO planes. For the SNS junctions, a low R(n)I(c) product, in the mu-V range, has been obtained. A good quality of the interface is required to obtain SNS bridge type junctions; we show that it corresponds to a contact resistivity less than some 10(-8) OMEGA-cm2.