Regensburg 2016 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 7: Focus Session: Ferroic Domain Walls I

DF 7.1: Hauptvortrag

Dienstag, 8. März 2016, 09:30–10:10, H25

Spin and charge transport in multiferroic domain walls — •Ramamoorthy Ramesh — University of California, Berkeley

Complex perovskite oxides exhibit a rich spectrum of functional responses, including magnetism, ferroelectricity, highly correlated electron behavior, superconductivity, etc. The basic materials physics of such materials provide the ideal playground for interdisciplinary scientific exploration. Among the large number of materials systems, there exists a small set of materials which exhibit multiple order parameters; these are known as multiferroics. Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. We reported the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO3. The origin and nature of the observed conductivity were probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Subsequent work in our program has demonstrated several key features of domain wall transport in manganites. Of course, one dream is to be able to create *metallic* walls in a ferroelectric matrix. I will describe our efforts in this direction.