Transmission electron microspy studies of ion migration in resistive switching platinum-manganite heterostructures

Abstract

Non-volatile resistance change under electric stimulation in many metal-oxides is a promising path to next generation memory devices. However, the underlying mechanisms are still not fully understood. in situ transmission electron microscopy experiments provide a powerful tool to elucidate these mechanisms. In this contribution, we demonstrate a TEM lamella geometry for in situ biasing with two xed electrode contacts ensuring low and stable contact resistances. We use Pr 1−x Ca x MnO 3−δ sandwiched by Pt electrodes as model system. The evolution of manganese valence state during electric stimulation in dierent environments is mapped by means of electron energy loss spectroscopy with high spatial resolution in STEM. Correlation of Mn valence with local oxygen content is found. In addition to electrically driven switching, beam-induced redox reactions in oxygen environment are observed. This eect might be restricted to thin lamellae. In general, our results support that bulk oxygen electromigration is the relevant mechanism for non-volatile resistive switching in PCMO.