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We have investigated the vortex state in a superconducting dice network using the Bitter decoration technique at several magnetic frustrations f=1/2 and 1/3. In contrast to other regular network geometries where the existence of a commensurate state was previouly demonstrated, no ordered state was observed in the dice network at f=1/2 and the observed vortex-vortex correlation length is close to one lattice cell., Comment: 7 pages, 6 figures, submitted to Europhysics Letter

We report the first detailed measurements on the critical current of periodic superconducting wire networks as a function of an external magnetic field. Sharp spikes are observed at integer and fractional reduced magnetic fluxes /0, where is the magnetic flux per unit cell of the network. The experimental results are discussed in terms of the depairing current for the 2D array. An approach based upon the band properties of the paired Electrons on the underlying lattice is proposed. This model explains the main features of the field and temperature dependence of the critical current without referring to pinning effects of the vortex lattice.

Measurements are reported of the derivatives dM/dH and dM/dT of the magnetization of a superconducting network near the superconducting transition temperature in a weak transverse magnetic field. The a.c. susceptibility dM/dH exhibits sharp peaks at integer and fractional number of flux quanta per cell as expected from the phase diagram (H, T) of the network. In contrast, the dM/dT measurements reveal distinct features, characteristic of the equilibrium state below the superconducting transition. These results are compared to recent theoretical predictions for the mixed state of a superconducting network.