IRREVERSIBLE MAGNETIC RESPONSE OF THE SIMPLEST 3-DIMENSIONAL JOSEPHSON-JUNCTION NETWORK

We describe the stationary magnetic states of the simplest three-dimensional (3D) Josephson-junction network, namely, a tetrahedron containing a junction on each side. In this system the Josephson junctions are coupled through inductances and the externally applied magnetic field H is directed along an arbitrary direction in space. We give a complete analytic treatment of the problem taking into account fluxoid quantization for each loop in the network. We also determine the lower threshold field H-gc1 for irreversible flux penetration for the tetrahedral network for two orientations of the held H, one perpendicular and one parallel to the base of the tetrahedron.