1. Institute of Materials for Electronics and Magnetism (IMEM-CNR), Parco Area delle Scienze 37/a, 43124 Parma, Italy
2. Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/a, 43124 Parma, Italy
3. Institute of Materials for Electronics and Magnetism (IMEM-CNR), FBK Trento unit, Via alla Cascata 56/C, 38123 Povo, Trento, Italy
4. NEST, Istituto Nanoscienze – CNR, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy