Electric field controllable Josephson junctions of high quality in highhyphen;Tcsuperconductors

摘要

Threehyphen;terminal Josephson junctions, the third terminal of which can be used to control the electronic properties of the device, are the key to a number of exciting device applications of highhyphen;Tcsuperconductors. To this end a novel device structure has been developed, which consists of an inverted metalhyphen;insulatorhyphen;superconductor fieldhyphen;effect transistor into which a bicrystal grain boundary junction is embedded. These devices are excellent Josephson junctions as exemplified by their currentndash;voltage characteristics and the magnetic field dependencies of the critical currents. The critical current of the junctions can be changed by 8percnt; per volt applied to the gate electrode, the gate currents being negligible. Because they are sensitive to electric as well as magnetic fields, the junctions can be controlled by two independent inputs. copy;1996 American Institute of Physics.