Order parameters and current-phase relations in 3He-B Josephson junctions through a porous layer -: art. no. 214501

Recent discoveries of the pi states in He-3-B Josephson junctions through an array of apertures and a single aperture have aroused much theoretical interest on the mechanism of pi states. Both tunneling junction and single orifice junction models were successfully applied to explain the occurrence of pi states and their relationship with the texture orientations of vectors in two He-3-B reservoirs. In this paper. we study a model He-3-B Josephson junction through a porous layer. The order parameters and current-phase relations are calculated self-consistently using the quasiclassical theory. In agreement with previous theories, the pi state is also observed when the (n) over cap 's are aligned antiparallel and normal to the porous layer. In this model, however, the pi state exists only when the coupling between two He-3-B reservoirs is strong, and the usual 0 state is present when the coupling diminishes. Being contrary to the single aperture case, the pi state in our model is robust only when the magnetic field is aligned either nearly normal to or within the porous layer.