1. Shanghai Key Laboratory of Magnetic Resonance School of Physics and Electronic Science East China Normal University Shanghai 200062 China
2. Key Laboratory of Spin Electron and Nanomaterials of Anhui Higher Education Institutes Suzhou University Suzhou 234000 China
3. International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science (NIMS) 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan
4. School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland Brisbane QLD 4072 Australia