1. CFisUC, Department of Physics, University of Coimbra, R. Larga, P-3004-516 Coimbra, Portugal
2. International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal
3. I3N, University of Aveiro, 3810-193 Aveiro, Portugal
4. Department of Physics, University of Aveiro, 3810-193 Aveiro, Portugal
5. Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland