1. Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax, B.P. 1171, Sfax 3000, Tunisia
2. University of Coimbra, CFisUC, Physics Department, Rua Larga, 3004-516 Coimbra, Portugal
3. I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
4. Physics Department, College of Science, Jouf University, Sakaka P.O. Box 2014, Saudi Arabia