1. Emerging Research Instruments Group, Korea Research Institute of Standards and Science (KRISS) , Daejeon , South Korea
2. Major in Nanoconvergence Measurement, University of Science and Technology , Daejeon , South Korea
3. Quantum Spin team, Korea Research Institute of Standards and Science (KRISS) , Daejeon , South Korea
4. Graduate School of Analytical Science and Technology, Chungnam Nationl University , Daejeon , South Korea