Resistive switching metal-insulator-metal structures were fabricated from epitaxial Fe-doped SrTiO3 thin films to study the distribution of oxygen vacancies in a switched memristor cell using a micro-focused X-ray beam. In addition to the main filament, It was found that the concentration of oxygen vacancies increases homogeneously over the whole electrode area during the electroforming procedure. The X-ray absorption near-edge structure (XANES) observed at the location of the filament exhibits distinct differences to the surrounding area, which were interpreted with full-multiple-scattering XANES calculations to derive from oxygen vacancy clustering in the first coordination shell around Fe.

Probing the Oxygen Vacancy Distribution in Resistive Switching Fe-SrTiO3 Metal-Insulator-Metal-Structures by Micro-X Ray Absorption Near-Edge Structure. C.Lenser, A.Kuzmin, J.Purans, A.Kalinko, R.Waser, R.Dittmann: Journal of Applied Physics, 2012, 111[7], 076101