Penetration depth of a superconducting superlattice.

We have measured the magnetic-flux expulsion of a superconducting superlattice and related it to the Meissner penetration depth. The temperature dependence of the penetration depth is in quantitative agreement with theoretical expectation based on mean-field theory. The zerotemperature penetration depth is found in excellent, quantitative agreement without adjustable parameters with theoretical predictions for dirty superconductors.