1. Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
2. Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, USA
3. Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
4. Department of Materials Design and Innovation, University at Buffalo, State University of New York, Buffalo, New York 14260, USA