Proton Dynamics in Hydrated BaZr 0.9 M 0.1 O 2.95 (M = Y and Sc) Investigated with Neutron Spin−Echo

International audience; Hydrated samples of the two proton conducting perovskites BaZr 0.9 M 0.1 O 2.95 (M = Y and Sc) were investigated using neutron spin−echo spectroscopy together with thermal gravimetric measurements, polarized neutron diffraction, and infrared spectroscopy, with the aim to determine how the atomic-scale proton dynamics depend on temperature, and type of dopant atom, M. The results show the presence of pronounced localized proton motions for temperatures above ca. 300 K, characterized by relaxation times on the order of picoseconds to nanoseconds and governed by a wide distribution of activation energies due to a heterogeneous distribution of proton sites present, with no strong dependence on the type of dopant atom.