title: Interstitial oxygen as a source of p-type conductivity in hexagonal manganites.
abstract: Hexagonal manganites, h-RMnO3(R=Sc, Y, Ho-Lu), have been intensively studied for their multiferroic properties, magnetoelectric coupling, topological defects and electrically conducting domain walls. Although point defects strongly affect the conductivity of transition metal oxides, the defect chemistry of h-RMnO3has received little attention. We use a combination of experiments and first principles electronic structure calculations to elucidate the effect of interstitial oxygen anions, Oi, on the electrical and structural properties of h-YMnO3. Enthalpy stabilized interstitial oxygen anions are shown to be the main source of p-type electronic conductivity, without reducing the spontaneous ferroelectric polarization. A low energy barrier interstitialcy mechanism is inferred from Density Functional Theory calculations to be the microscopic migration path of Oi. Since the Oicontent governs the concentration of charge carrier holes, controlling the thermal and atmospheric history provides a simple and fully reversible way of tuning the electrical properties of h-RMnO3.
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Sandra H
authors.initials: SH
authors.lastname: Skjærvø
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Espen T
authors.initials: ET
authors.lastname: Wefring
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Silje K
authors.initials: SK
authors.lastname: Nesdal
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Nikolai H
authors.initials: NH
authors.lastname: Gaukås
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Gerhard H
authors.initials: GH
authors.lastname: Olsen
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Julia
authors.initials: J
authors.lastname: Glaum
authors.affiliation: Department of Electronics and Telecommunications, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Thomas
authors.identifier: 0000-0003-0787-8476
authors.initials: T
authors.lastname: Tybell
authors.affiliation: Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
authors.forename: Sverre M
authors.initials: SM
authors.lastname: Selbach