1. Laboratoire de Physique de l'Etat Condensé, Université du Maine, UMR 6087 CNRS, 72085 Le Mans Cedex 09 France, Laboratoire Chimie de la Matière Condensée, Université Pierre et Marie Curie, 4 place Jussieu, 75 252, Paris Cedex 05, France, Department of Chemical and Nuclear Engineering and Center for Micro-Engineered Materials, Advanced Materials Laboratory, University of New Mexico, 1001 University Boulevard SE, Albuquerque, New Mexico 87106, and Sandia National Laboratories, Albuquerque, New Mexico 87185