1. Sensors & Electron Devices Directorate, U.S. Army Research Laboratory, Adelphi, Maryland 20783, United States
2. Engineering
Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
3. Department
of Physics, Astronomy, and Geosciences, Towson University, Towson, Maryland 21252, United States
4. Department
of Physics and National High Magnetic Field Lab, Florida State University, Tallahassee, Florida 32310, United States
5. Institute
of Carbon Science and Technology, Faculty of Engineering, Shinshu University, Nagano 380-8553, Japan