Chemical insight into resistive switching devices by HAXPES

Complex transition metal oxides may exhibit large electrically driven changes of resistance, thereby attracting considerable attention for the development of non-volatile storage devices. We have used core-level Hard X-ray Photoelectron Spectroscopy (HAXPES) to prove experimentally that resistive switching in Ti/Pr0.48Ca0.52MnO3/SrRuO3 (Ti/PCMO/SRO) thin film heterostructures depends on a redox process occurring on the Ti side of the Ti/PCMO interface. The resistance states are determined by the amount of oxidized Ti ions in the stack, varied through a reversible redox-reaction leading to the formation and shortening of an insulating tunnel barrier.