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.

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