1. Department of Physics (IFM), Linköping University, Linköping 583 30, Sweden
2. Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, P.R. China
3. High Field Magnet Laboratory (HFML - EMFL), Radboud University, Toernooiveld 7, Nijmegen 6525 ED, The Netherlands
4. Department of Physics and Astronomy, Uppsala University, Uppsala SE-75120, Sweden