Tuning Electrochemical Response in Ion-Gel-Gated La<sub>1-<i>x</i></sub>Sr<i><sub>x</sub></i>CoO<sub>3-δ</sub> Films via Sr-doping and strain

ORAL

Abstract

Electrolyte gating has proven powerful for controlling electronic, magnetic, and optical properties of materials such as oxides. Understanding the true gating mechanisms (i.e., electrostatic vs. electrochemical), however, particularly in oxides, where O vacancy formation and diffusion is often facile, remains challenging. Here, we present a study of the Sr-doping and strain dependence of the ion-gel gate response of La1-xSrxCoO3-δ (LSCO) films (0 < x < 0.7), using transport, magnetometry, and operando synchrotron X-ray diffraction. Consistent with prior work, small negative gate biases induce reversible electrostatic hole accumulation, whereas positive biases induce oxygen vacancies (VO) [1,2]. The window of reversibility and bias threshold for VO formation are found to systematically decrease with x, consistent with higher electrochemical activity of Co4+ than Co3+; tensile strain similarly promotes electrochemical response. At sufficiently high x, a topotactic transformation to a brownmillerite phase occurs. These findings are placed in the context of prior literature and discussed in terms of x-dependent variations in VO formation enthalpy and diffusivity.

*Work supported by NSF MRSEC.

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Presenters

  • VIPUL CHATURVEDI

    • Chemical Engineering and Material Science, University of Minnesota

Authors

  • VIPUL CHATURVEDI

    • Chemical Engineering and Material Science, University of Minnesota

  • William M Postiglione

    • Chemical Engineering and Material Science, University of Minnesota

  • Biqiong Yu

    • School of Physics and Astronomy, University of Minnesota
    • University of Minnesota

  • Wojciech Tabis

    • University of Minnesota
    • LNCMI Toulouse
    • Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow, Poland

  • Sajna Hameed

    • School of Physics and Astronomy, University of Minnesota
    • School of Physics and Astronomy, University of Minnesota Twin Cities

  • Nikolaos Biniskos

    • School of Physics and Astronomy, University of Minnesota
    • University of Minnesota

  • Hua Zhou

    • Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
    • Advanced Photon Source, Argonne National Laboratory
    • Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA

  • Zhan Zhang

    • Argonne National Lab
    • Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
    • Advanced Photon Source, Argonne National Laboratory

  • Martin Greven

    • School of Physics and Astronomy, University of Minnesota
    • University of Minnesota
    • Physics and Astronomy, University of Minnesota
    • School of Physics and Astronomy, University of Minnesota Twin Cities

  • Chris Leighton

    • University of Minnesota
    • Chemical Engineering and Material Science, University of Minnesota