trontium deficient thin SrTiO3 films show resistive switching that is assumed to be related to ferroelectric antisite defects where Ti occupies a Sr position. With increasing deficiency, these defects form polar regions (domains) in the lattice that can be switched by means of an electric field. In our model, the orientation of the spontaneous polarization defines the resistance through the film leading to the resistive switching behaviour. In this proposal, we want to verify the relation of ferroelectric and resistive switchen. In addition, we intend to determine the structure of polar defects in strontium deficient SrTiO3 as function of applied electric field . This will be done by a combination of X-ray absorption spectroscopy (XAS) and in-situ resonant X-ray diffraction (RXD).