1. Nano Engineering and Spintronic Technologies Group, Department of Computer Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
2. Department of Physics and Astronomy & Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
3. The Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Daresbury, Warrington WA4 4AD, United Kingdom