1. Center for High Pressure Science and Technology Advanced Research; Beijing 100094 P. R. China
2. Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics; Nankai University; Tianjin 300071 China
3. Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry; China Academy of Engineering Physics; Mianyang 621999 P. R. China
4. ISIS Neutron and Muon Facility; Rutherford Appleton Laboratory; Chilton Didcot Oxon OX11 0QX UK
5. J-PARC Center, Japan Atomic Energy Agency; Tokai Ibaraki 319-1195 Japan
6. Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge TN 37831 USA
7. Geophysical Lab; Carnegie Institution of Washington; 5251 Broad Branch Road NW Washington, DC 20015 USA
8. Advanced Photon Source; Argonne National Laboratory; Lemont IL 60439 USA
9. Pohang Accelerator Laboratory, POSTECH; Pohang 790-784 Republic of Korea