2-FOLD STACKS OF LONG JOSEPHSON-JUNCTIONS WITH DIFFERENT PARAMETERS

The properties of the two-layer magnetically coupled long Josephson ju nction stacks are investigated theoretically. An expression for the Sw ihart velocities (c) over bar(+)(c) over bar(-) is given for the case of different junction parameters. It is predictd that for asymmetric s tack the first critical field H-c1 is represented by two values H-c1(d own arrow) and H-c1(up arrow) different from the fields H-c1(A) and H- c1(B) that characterize separate junctions. A calculation of the first critical H-c1(down arrow) as a function of the junction parameters is made for the case of small difference in effective magnetic field pen etration depths of the junctions.