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Technology

This Josephson junction is a two terminal trilayer thin film structure consisting of two superconductors separated by an ultra-thin tunnel barrier insulator. MgB2 is an optimal superconductor for this application since it can be fabricated by point contact into ramp type and various planar structures. This device functions at temperatures close to its superconducting ordering temperature. Since the operating temperature is above 20K, the device can work by simply cooling with closed cycle refrigeration that uses only electrical power. This gets rid of the need for cryogenic liquids. The trilayer structure is made on a buffered semiconductor wafer, grown in situ in one step at temperatures below 300 C. Molecular beam epitaxy is used to create the structure,  and photolithography and electron-beam lithography are used to pattern the Josephson junction into micron and nano sized devices. MgB2 based JJ devices make it ideal to develop superconductive electronics that will be essential in the future for device operation in the picosecond time scale with essentially no energy loss.