1. Stanford Institute
for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
2. van der Waals-Zeeman Institute, University of Amsterdam, 1018XE Amsterdam, The Netherlands
3. Spectroscopy and Coherent Scattering Instrument, European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
4. Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, Auguste-Piccard-Hof
1, 8093 Zürich, Switzerland
5. Department
of Physics, Temple University, 1925 N. 12th Street, Philadelphia, Pennsylvania 19122, United States
6. Advanced
Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
7. San Jose Research Center, HGST a Western Digital Company, 3403 Yerba Buena Road, San
Jose, California 95135, United States
8. Magnetic Materials Unit, National Institute for Materials Science, Tsukuba 305-0047, Japan
9. Center for Memory and Recording Research, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0401, United States