Using electrochemical deposition of Pb in the pores of templates prepared by self-assembly from colloidal suspensions of polystyrene latex spheres, well ordered superconducting antidot arrays with spherically shaped holes are fabricated. In contrast to conventional lithographic arrays the samples with spherical cavities demonstrate significantly reduced pinning strength favoring the formation of commensurate states. The ac-flux penetration acquires a hybrid intra-and intervalley regime. For high ac drives an unusual inversion to paramagnetic ac shielding is found at commensurate states.

We present results of electrochemical deposition of superconducting Pb in the pores of templates prepared by self-assembly from colloidal suspensions of polystyrene latex spheres. This technique enables us to create highly ordered superconducting nano-structures with 3D architectures on length scales ranging from 50 - 1000 nm. The prepared samples show pronounced Little-Parks oscillations in Tc and matching effects in magnetization and magnetic susceptibility. Real and imaginary parts of susceptibility follow a universal Cole-Cole curve. Self-field effects play an important role in commensurability behaviour of magnetic moment at low temperatures.Comment: 12 pages, 6 figure

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We study the interactions of the vortex lattice with a periodic square array of holes in a superconducting Nb film using magnetic and resistive measurements. Three different temperature regions have been observed. They are governed by interplay between vortexvortex interactions and pinning by holes. At low temperatures flux jumps suppress the commensurability anomalies. In all measurements a peak has been observed close to commensurate states 5-7. The Cole-Cole plot reveals significant changes in the flux penetration mechanism at this point.

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