I. M. Babich,1,2 E. H. Brandt,1 G. P. Mikitik,1,2 and E. Zeldov3 1Max-Planck-Institut fur Metallforschung, D-70506 Stuttgart, Germany 2B. Verkin Institute for Low Temperature Physics & Engineering, Ukrainian Academy of Sciences, Kharkov 61103, Ukraine 3Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel Received 16 November 2009; revised manuscript received 21 January 2010; published 22 February 2010