Superconducting arrays in a magnetic field: Effects of lattice structure and a possible double transition

We report the results of extensive Monte Carlo simulations and mean-field calculations for superconducting arrays in a transverse magnetic field. Two new lattices are studied: triangular and honeycomb. The universality class of the transition is found to depend on both field and lattice type. In the triangular lattice at a field of {} flux quantum per triangle, there are some indications that the superconducting-normal transformation proceeds by two separate phase transitions.