Proton conduction path in RbH(SeO) studied by high temperature neutron single crystal diffraction

Kiyanagi, Ryoji  ; Ishikawa, Yoshihisa*; Noda, Yukio*

RbH(SeO) is known to exhibit a super protonic conductivity at rather low temperature and has attracted much attention. The protonic conductivity emerges upon a structural phase transition, thus the protonic conductivity is believed to have close relation with the crystal structure. In order to clarify the relation between the internal structure and the realization of the super protonic conductivity as well as the conduction mechanism, single crystal neutron diffraction was carried out. The results showed that the hydrogen-bond length monotonically increases as the temperature increases and no peculiar behavior in the internal structure has been recognized. The structure analysis in the proton-conducting phase revealed that the hydrogen atoms (protons) migrate over the equivalent sites via intermediate sites.