Josephson vortices at tricrystal boundaries

Josephson vortices at tricrystal boundaries with and without a pi junction in zero applied field are considered. It is shown that if the three tricrys tal arms are conventional junctions, a one-flux-quantum phi(0) vortex at or near the intersection has lower energy than one far from the intersection. If the largest Josephson length exceeds the sum of the other two, the tric rystal ceases to be a pinning site. If one of the tricrystal arms is a pi j unction, a theta(0)/2 vortex at the intersection is the ground state of the system, and an even number of phi(0)/2 vortices is forbidden, whereas 3 ph i(0)/2 and 5 phi(0)/2 correspond to possible but, in general, metastable st ates. For certain combinations of Josephson lengths, the 3 phi(0)/2 state h as lower energy than the combined energy of the phi(0)/2 vortex at the tric rystal joint and phi(0) vortex far from the joint. Conditions are discussed under which the 3 phi(0)/2 vortex can be observed.