Nonlocality in superconducting metals: an ultra-high precision magnetic penetration depth study

In previous reports the temperature dependence of the penetration depth lambda(T) of some nonlocal superconducting metals has been found to be in disagreement with the behavior expected from the nonlocal BCS theory. Instead, lambda(T) was close to the local BCS prediction. Here we present high-precision measurements of lambda(T) in Al, Cd, and Zn down to 30 mK, which are in excellent agreement with the prediction of the nonlocal BCS electrodynamics without using adjustable parameters. (C) 2003 Elsevier Science B.V. All rights reserved.