The conduction behavior of Rh-doped AZrO3 (A = Ba, Sr, Ca) was investigated by using electrical and electrochemical methods at elevated temperatures. The protonic conductivity of the Rh-doped AZrO3 in H was close to that of the Y-doped AZrO3. The transport numbers of the ions in H were unity in all the samples examined here. Under high-O partial pressures, the conductivities of the Rh-doped AZrO3 were lower than those of the Y- or In-doped AZrO3, suggesting the low conductivity of electron holes. The O partial pressure dependence of the conductivity indicated that a change in the valence of the Rh ion might suppress the generation of mobile holes under a high-O partial pressure condition.

Protonic Conduction in Rh-Doped AZrO3 (A = Ba, Sr, Ca). T.Shimura, K.Esaka, H.Matsumoto, H.Iwahara: Solid State Ionics, 2002, 149[3-4], 237-46