Grain boundary Josephson element with metal oxide high-temperature superconductor material, process for its production and use of the element

摘要

The junction is made with ceramic oxide superconducting material deposited epitaxially on a substrate with a height step in its surface which produces grain boundaries at both upper and lower level. The feature is that the width of the superconducting material (3c) on the step (B) and (3b,13b) on the lower level (b1,b2) are much larger than that of the film (3a) on the upper surface (b1). This is pref. realised by defining 2 parallel structures (3,13) of which one (3) has a narrow track and the other a much wider track (13) which are connected together at least via the film on the slope (10). The width (b2) is pref. at least 3 times the width (b1). The angle of the slope with the horizontal planes is pref. at least 45 deg. At least one junction is used, with a slit, to form a SQUID device. USE/ADVANTAGE - The method to produce a grain boundary induced Josephson effect is more reliable and easier to control than currently available techniques. The effect operates only in the upper layer of the film and the effect can be avoided at the lower part of the slope by providing a large shunting area. The process allows SQUIDs to be constructed easily.