Proton Dynamics and Structural Modifications in the Protonic Conductor Perovskites

Quasi-elastic neutron scattering, neutron diffraction as well as in situ and ex situ Raman studies were performed on the proton conducting (Ba/Sr)Zr(1-x)Ln(x)O(3-delta) dense ceramics. The results confirm the homogeneous distribution of the bulk protonic species, their variable content as a function of Ln content and sample processing as well as successive re-orientation local motion between 400 and 600 degrees C. The analysis of the elastic incoherent structure factor suggests the complex motion of proton between different sites and with different length jumps. The proton dynamics are accompanied by the presence of structural phase transitions near 350/450 and 550 degrees C as well as by the changes of conductivity activation energy.