1. Instituto de Microelectrónica de Sevilla, CSIC, Universidad de Sevilla, Seville, Spain
2. NanOsc AB, Kista, Sweden
3. Department of Physics, Applied Spintronics Group, University of Gothenburg, Gothenburg, Sweden
4. Electrical and Computer Engineering Department, Integrated Circuits and Electronics Laboratory (ICELab), Aarhus University, Aarhus, Denmark