SUPERCONDUCTING TUNNEL JUNCTION ELEMENT

摘要

PURPOSE:To obtain a high quality tunnel type Josephson junction element which can be operated at a high temperature without necessity of liquid helium by providing a diffused barrier layer made of Pt at least on one of a barrier and a first superconducting electrode or the barrier and a second superconducting electrode therebetween. CONSTITUTION:A lower Ba1-xKxBiO3 thin film 2 is deposited about 250nm thick on a substrate 1 made of an SrTiO3 in plane (100) in a sputtering device having three magnetron cathodes by using a Ba0.6K0.4BiO3 sintered target. Then, a BaBiO3 barrier layer 3 of about 0.13nm thick is deposited on the film 2 in the same device by using a BaBiO3 sintered target. Further, a Pt layer 4 of 5nm or less thick is deposited on the layer 3 by sputtering. Eventually, an upper Ba1-xKxBiO3 thin film 5 is deposited about 150nm thick on the layer 4. A superconducting tunnel junction element is formed by using these four laminated layer films.