Amphoteric behaviour of Er3+ dopants in BaTiO3: an Er-LIII edge EXAFS assessment

Er-doped BaTiO3 samples with nominal compositions BaEr0.08Ti0.92O2.96 and Ba0.96Er0.08Ti0.96O3 have been analyzed with Er-LIII edge XAFS. The first sample shows predominant Er substitution on the Ti site of the perovskite structure, the second one shows almost equal occupancy of Er on Ba and Ti sites, thus assessing the ability of the stoichiometry to control the doping mechanism. In more detail, in both cases the main doping mechanism is not exclusive. Er-O distances determined by EXAFS are in good agreement with static lattice simulations.