1. Laboratory for High Performance Ceramics, Empa, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
2. Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom
3. Laboratory for Muon Spin Spectroscopy (LMU), Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen CH-5232, Switzerland
4. Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen CH-5232, Switzerland
5. Department for Hydrogen Technology, Institute for Energy Technology, Kjeller NO-2027, Norway
6. Department of Physics, University of Zurich, Winterthurerstrasse 190, Zurich CH-8057, Switzerland