1. Centre of Physics of University of Minho and Porto (CF-UM-UP), Campus de Gualtar, 4710-057 Braga, Portugal
2. Department of Physics, School of Basic and Applied Science, Central University of Tamil Nadu, 610 101 Thiruvarur, India
3. Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 18000 Prague 8, Czech Republic
4. National Institute of Materials Physics, 105 Bis Atomistilor, 077125 Magurele, Romania
5. IFIMUP & Department of Physics and Astronomy, Sciences Faculty, University of Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal