1. Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
2. Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
3. Department of Physics, Washington University, St. Louis, Missouri 63130, United States
4. Department of Physics, Southern Illinois University, Edwardsville, Illinois 62026, United States
5. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States