Muon diffusion and trapping in proton conducting oxides
Abstract Trapping as a main feature of proton diffusion in proton conducting oxides was investigated by means of muon spin relaxation measurements, with the positive muon as tracer. In Sc-doped SrZrO 3 , a system with representative physico-chemical properties and favourable nuclear magnetic moments, the muons are trapped at single Sc ions at a distance of 2.49 A with a binding energy of 0.2 eV, in accordance with previous proton results. The muons form muoxide ions which are directed along the bisector of two oxygen–oxygen connection lines. The μSR spectra could quantitatively be described in terms of a two-state model for the muon diffusion comprising random sequences of trapping events and free diffusion periods.