Regensburg 2013 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 12: Poster 1

DF 12.65: Poster

Tuesday, March 12, 2013, 10:30–13:30, Poster D

Electronic and magnetic properties of Ti₄O₇ and Ti₅O₉ Magnéli phases — Ivetta V. Slipukhina, •Konstantin Z. Rushchanskii, Stefan Blügel, and Marjana Ležaić — Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

For several decades binary transition-metal oxides have attracted increasing attention as resistively switching materials. Resistive switching in many of these oxides is claimed to be based on the formation and disruption of highly-conductive filaments, through which the current flow is realized. However, still very little is known about the composition, structure and dimensions of these filaments. Recent low-temperature conductivity and in situ current-voltage measurements confirmed that the conducting filaments in Pt/TiO₂/Pt [1], as well as Fe-doped SrTiO₃ [2] are composed of Magnéli phases Ti_nO_2n−1 (mostly n=4 or 5), which are mixed-valence compounds with two Ti³⁺ (3d¹ electronic configuration) and (n−2) Ti⁴⁺ (3d⁰ configuration) ions.

In this work we aimed to develop a fundamental understanding of the mechanisms that underlie the phase transitions in Magnéli phases like Ti₅O₉ and Ti₄O₇. With this aim we performed DFT calculations in order to illuminate the changes in their electronic structure on a microscopic level and establish relations between the structural, electronic and magnetic properties and their role in phase transitions.

We acknowledge the support by SFB917-Nanoswitches and the Helmholtz Young Investigators Group Programme VH-NG-409.

[1] D.-H. Kwon et al., Nature Nanotech. 5, 148 (2010).
R. Münstermann et al., Advanced Materials 22, 4819 (2010).