1. Department of Physics, Eastern Illinois University, Charleston, Illinois 61920, United States
2. Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
3. Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
4. Department of Materials Science and Engineering, Korea Aerospace University, Goyang-si, Gyeonggi-do 10540, Korea
5. Department of Materials Physics, Sookmyung Women’s University, Seoul 04310, Korea