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.