Micro-SQUID microscopy of vortices in a perforated superconducting Al film

A scanning micro-superconducting quantum interference-device microscope is used to directly image vortices in a superconducting Al thin film. We observe the temperature dependence of the vortex distribution in a regular defect (hole) array patterned into the Al film. The direct observation of the localized superconducting state around the holes is shown as well as the effect of the hole size on nucleation of the superconducting state.