1. Biophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
2. UCL Healthcare Biomagnetics and Nanomaterials Laboratories, The Royal Institution, 21 Albemarle Street, London, W1S 4BS, UK
3. Condensed Matter and Materials Physics, Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
4. ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX11 0QX, UK
5. School of Physics, Engineering and Technology, University of York, Heslington, York, YO10 5DD, UK
6. The York-JEOL Nanocentre, York Science Park, Heslington, York YO10 5BR, UK