Direct visualization of the vortex distributions in a superconducting film with a Penrose array of magnetic pinning centers: Symmetry induced giant vortex state

Using scanning Hall probe microscopy a direct visualization of the flux distribution in a Pb film covering a fivefold Penrose array of Co dots is obtained. We demonstrate that stable vortex configurations can be found for fields H similar to 0.8H(1), H(1) and 1.6H(1), where H(1) corresponds to one flux quantum per pinning site. The vortex pattern at 0.8H(1) corresponds to one vacancy in one of the vertices of the thin tiles whereas at 1.6H(1) the vortex structure can be associated with one interstitial vortex inside each thick tile. Strikingly, for H = 1.6H(1) interstitial and pinned vortices arrange themselves in ring-like structures ("vortex corrals") which favor the formation of a giant vortex state at their center. (C) 2010 Published by Elsevier B.V.