1. CENIMAT|i3N, Department of Materials Science, School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
2. CENIMAT|i3N, Department of Physics, School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
3. I3N and Physics Department, Aveiro University, 3810-193 Aveiro, Portugal