Probing surface valence, magnetic property, and oxide ion diffusion pathway in B-site ordered perovskite-type Ba2Ca0.67M0.33NbO6 − δ (MMn, Fe, Co)

• XPS study of bulk and surface valences of transition metals in perovskites
• Magnetic measurement reveals the long range ordering of spin in the structures.
• Oxide ions transport pathways are less sensitive to transition metal ions.
• MD simulations at temperatures ≥ 800 K show a long range O2– transport.

Here, we report the valence of transition metals at surface, magnetic ordering and oxide-ion transport pathway of the double perovskite-type Ba2Ca0.67M0.33NbO6 − δ (MMn, Fe, Co). In-situ X-ray photoelectron spectroscopy (XPS) reveals that the surface valences for Mn and Co-doped Ba2Ca0.67M0.33NbO6 − δ are 2.5 + and 2 +, respectively at 700 °C. All the Ba2Ca0.67M0.33NbO6 − δ samples are paramagnetic with no long-range cooperative interaction between individual spins. Bond valence sum (BVS) map and molecular dynamics (MD) reveal that the oxide ion migration pathways are isotropic in all investigated Ba2Ca0.67M0.33NbO6 − δ. In particular, MD simulations (≥ 800 K) show a long-range oxide ion transport with an activation energy of 0.69 eV for Ba2Ca0.67Co0.33NbO6 − δ.

Surface valence, magnetic ordering and oxide-ion transport properties of Ba2Ca0.67M0.33NbO6 − δ (MMn, Fe, Co).Figure optionsDownload as PowerPoint slide