CRITICAL CURRENTS AND FLUX PHASES IN SUPERCONDUCTING MULTILAYERS WITHA LATTICE OF SUBMICROMETER HOLES

Magnetization studies of critical currents J(C)(H-perpendicular to,T) have been carried out on Pb/Ge multilayers with a square lattice of su bmicrometer holes. Sharp peaks in J(C)(H-perpendicular to ) have been observed at integer H-n and rational H-k/l matching fields. The existe nce of multi-quanta vortices confined by the holes is confirmed. New r ational flux line patterns at H = H-k/l have been identified. The depe ndence of the pinning force on the number of flux lines trapped by eac h hole is analyzed.