1. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
2. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
3. Materials Science and Technology Division, Oak Ridge, Tennessee 37831, United States
4. Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
5. Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
6. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907, United States