1. I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
2. CENIMAT-I3N and Materials Science Department, NOVA School of Science and Technology, Campus de Caparica, 2829-516 Caparica, Portugal
3. CENIMAT-I3N and Physics Department, NOVA School of Science and Technology, Campus de Caparica, 2829-516 Caparica, Portugal