Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 39: Resistive Effects I

DS 39.3: Talk

Thursday, March 10, 2016, 10:00–10:15, H8

Resistive switching devices with ultrathin graphene top electrodes for in situ spectromicroscopic characterization — •Richard Valenta, Christoph Bäumer, Christoph Schmitz, David Müller, Nicolas Raab, Slavomir Nemsak, Claus Michael Schneider, Rainer Waser, and Regina Dittmann — Peter Grünberg Institut and JARA-Fit, Forschungszentrum Jülich, 52425 Jülich

Resistively switching transition metal oxides are gaining in importance as a promising alternative for future non-volatile memory. Although the switching mechanism is not fully understood, it has been shown that nanoscale redox reactions are responsible for a localized change of the resistance. Spectromicroscopic measurements present a powerful tool to investigate such localized chemical and structural changes and can give a deeper understanding of the switching mechanism.

Here we will present local changes in the electronic structure of SrTiO₃-based memristive devices in two different resistance states, utilizing in-operando photoemission electron microscopy measurements (PEEM). Since PEEM is very surface sensitive, ultrathin graphene top electrodes are used to attain spectroscopic information from the active SrTiO₃ layer of a functioning device. Localized changes of the work function as well as changes in the O K-edge spectra indicate that the resistance change coincides with redox reactions within confined switching filaments. This finding substantiates the expected filamentary switching of SrTiO₃ and confirms that the resistance change is caused by oxygen migration.