1. Laboratory of Solid State Physics, Faculty of Science, Sidi Mohamed Ben Abdellah University, Fez, Morocco
2. Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat, Morocco
3. Hassan II Academy of Science and Technology, Rabat, Morocco
4. Equipe de Physique du Solide, Laboratoire LIPI, Ecole Normale Supérieure, Fes, Morocco