Fig. 6: TOF-SIMS and XAS results for the surface region of particles.

a TOF-SIMS analyses directly reveal less detection of 18O at the surface of Ba4NbIr3O12 particles. Each error bar represents the range from the maximum to the minimum value of three data points. b A series of O K-edges obtained from XAS are shown. The absorption energy difference (Δ), which is proportional to the ligand field splitting, between the first and second peaks is observed to increase after 600 cycles (Δ1 < Δ2).