Fig. 2: X-ray absorption spectroscopy results of (111)-oriented LaNiO3 films taken at ALS beamline 6.3.1.
From: Emergent long-range magnetic order in ultrathin (111)-oriented LaNiO3 films

Note that the La peak located at 849 eV has been subtracted out using peak fitting software. Splitting of the Ni L2 peak indicates an increased concentration of Ni2+ ions in the LaNiO3 films.