1. IHP—Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
2. Peter Grünberg Institute 9 (PGI-9) and JARA-Fundamentals of Future Information Technologies (JARA-FIT), Forschungszentrum Jülich, 52425 Jülich, Germany
3. Pollard Institute, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, U.K.
4. National Institute of Materials Physics, 405A Atomistilor Street, 077125 Magurele, Romania
5. Dipartimento di Scienze, Università Roma Tre, Viale G. Marconi 446, 00146 Roma, Italy