Transport Properties of Epitaxial YBa sub 2 Cu sub 3 O sub x Films at Step Edges

To study the current-carrying capability of interconnections between conducting planes in a YBa sub 2 Cu sub 3 O sub x -insulator multilayer system, the transport properties of laser-depositd YBa sub 2 Cu sub 3 O sub x striplines at different step edges in < 100 > SrTiO sub 3 substrates were investigated. Step edges with various heights between 100-800 nm and slope angles a = 2.5, 10, 25, 40, and 65 deg were fabricated by Ar exp + ion milling. The previous ionmilling of one part of the substrate does not affect the crystal growth and the transport properties of the superconductor, which has been checked by electrical and X-ray measurements. Two ways for a high transport current between conducting planes were realized. At flat angles up to 30 deg , a critical current density of > 10 exp 6 A/cm exp 2 at 77K can be achieved for a step stripline with film thickness d sub 0 smaller than the step height h. If the film thickness d sub 0 is larger than the step height, high superconducting current densities can also be achieved for a > 65 deg C.