  We demonstrate the applicability of studying the proton dynamics in
proton-conducting perovskites using neutron spin-echo spectroscopy, a powerful
method hitherto neglected for studies of the proton dynamics in ceramic proton
conductors. By combining our neutron spin-echo results of hydrated
BaZr0.90Y0.10O2.95 with results obtained from kinetic modeling based on
first-principles calculations we show that already over a length-scale as short
as 2 nm the long-range proton self-diffusion is observed, and the likely effect
of dopant atoms acting as trapping centers has averaged out.
