SUPERCONDUCTING VORTICES IN TRIANGULAR AND SQUARE JOSEPHSON-JUNCTION ARRAYS

Experiments probing vortex dynamics in square and triangular Supercond ucting-Normal-Superconducting Josephson junction arrays are reviewed. A low frequency two coil mutual inductance technique allows to investi gate phase coherence in these samples. In a perpendicular magnetic fie ld the interaction of the field induced vortices with the periodic pin ning structure provided by the array leads to frustration effects whic h, interestingly enough, differ in the two types of arrays. This diffe rence in behavior is mainly due to the smaller pinning energy in the t riangular array.