Proton dynamics in La0.8Ba1.2GaO3.9 · nH2O studied by quasielastic incoherent neutron scattering

•Proton diffusion measured by high-resolution quasielastic neutron scattering.•The activation energy for proton diffusion is 0.5 eV.•Proton MSD 0.7 Å2 connected to the long-range proton diffusion•Better understanding of the microscopic proton diffusion process obtained.

La0.8Ba1.2GaO3.9 · nH2O presents an interesting system with tetrahedral network of GaO4, and high oxide ion and proton conductivities. High-resolution quasielastic incoherent neutron scattering experiments were performed to gain better understanding of the proton conduction mechanism in tetrahedral systems. Translational long-range proton diffusion was observed. The activation energy for this process is 0.5 eV. Mean-square-displacement of 0.7 Å2 for protons was obtained for the temperature range where the long-range proton diffusion occurs.