1. Department of Physics, University of Alabama at Birmingham, 1300 University Blvd., Birmingham AL, 35294 USA
2. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
3. Clarion University, 840 Wood St, Clarion, PA 16214, USA
4. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA