JOSEPHSON VORTEX-FLOW TRANSISTORS BASED ON PARALLEL ARRAYS OF YBA2CU3O7-DELTA BICRYSTAL GRAIN-BOUNDARY JUNCTIONS

Three-terminal electronic devices based on flux-flow phenomena have at tracted considerable interest due to their potential application in th e interface between superconducting and semiconducting electronics. We have fabricated Josephson vortex flow transistors based on parallel a rrays of YBa2Cu3O7-delta (YBCO) bicrystal Grain Boundary Junctions (GB Js). The array critical current I-c has been measured as a function of an external magnetic field B or the magnetic field of the current I-c trl that is fed through the control line coupled inductively to the ar ray. By varying the device geometry we have studied the influence of t he coupling of the magnetic control and the array parameters such as t he number N of discrete Josephson elements and the screening parameter beta(L) on the I-c(B) dependences of the arrays. Going from beta(L) m uch less than 1 to beta(L) much greater than 1 the measured I-c(B) cur ves changed from a dependence similar to the diffraction pattern of a grid to a dependence dominated by the parameters of a single array cel l. The impact on the available current gain is discussed.