1. Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
2. IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
3. Faculty of Science and Technology and MESA+ Institute for Nanotechnology, Inorganic Materials Science, University of Twente,
P.O. Box 217, 7500 AE Enschede, The Netherlands
4. National Institute of Materials Physics, 405A Atomistilor, 077125 Magurele, Romania
5. Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, 610101 Thiruvarur, India