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