Superconducting vortices in triangular and square Josephson junction arrays

Experiments probing vortex dynamics in square and triangular Superconducting-Normal-Superconducting Josephson junction arrays are reviewed. A low frequency two coil mutual inductance technique allows to investigate phase coherence in these samples. In a perpendicular magnetic field the interaction of the field induced vortices with the periodic pinning structure provided by the array leads to frustration effects which, interestingly enough, differ in the two types of arrays. This difference in behavior is mainly due to the smaller pinning energy in the triangular array. (orig.)