Commensurability effects in superconducting Nb films with quasiperiodic   pinning arrays
  We study experimentally the critical depinning current Ic versus applied magnetic field B in Nb thin films which contain 2D arrays of circular antidots placed on the nodes of quasiperiodic (QP) fivefold Penrose lattices. Close to the transition temperature Tc we observe matching of the vortex lattice with the QP pinning array, confirming essential features in the Ic(B) patterns as predicted by Misko et al. [Phys. Rev. Lett, vol.95, 177007 (2005)]. We find a significant enhancement in Ic(B) for QP pinning arrays in comparison to Ic in samples with randomly distributed antidots or no antidots. 
M. Kemmler, C. Guerlich, A. Sterck, H. Poehler, M. Neuhaus, M. Siegel,   R. Kleiner, D. Koelle