1. D. H. Lowndes, D. B. Geohegan, D. P. Norton, and C. M. Rouleau are in the Solid State Division, Oak Ridge National Laboratory, Post Office Box 2008, Oak Ridge, TN 37831-6056, USA.
2. A. A. Puretzky is at the Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Russia.