1. Department of Earth Science and Engineering Imperial College London, South Kensington Campus London UK
2. Now at School of Physics and Astronomy, Kelvin Building University of Glasgow Glasgow UK
3. Ernst Ruska‐Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute Forschungszentrum Jülich Jülich Germany
4. School of GeoSciences University of Edinburgh Edinburgh UK
5. Department of Physics Technical University of Denmark Kongens Lyngby Denmark