Deterministically robust switching of ferroelectric polarization and spin cycloidal polarity in (111) monodomain BiFeO3 thin films

ORAL

Abstract

(111) BiFeO3 (BFO) thin film with single ferroelectric (FE), ferroelastic and antiferromagnetic (AFM) domains is desirable toward a deterministically switchable (by an electric field) memory device, as it has the highest ferroelectric polarization ever reported. However, it is extremely challenging to realize. Here, we show that epitaxial BFO film grown on orthorhombic NdGaO3 (NGO) (011)o substrate buffered by a thin SrRuO3 layer exhibits single FE, ferroelastic and AFM domains as probed by P-E loop (and PFM), synchrotron X-ray and non-resonant X-ray magnetic scattering measurements. Importantly, its single domain nature is found to be very robust over 10,000 times electric field switching of FE polarization and associated spin-cycloidal polarity, which is remarkable as BFO grown on cubic SrTiO3 is not truly single domain (single FE, but 3-AFM domains) and can degrade over less number of switching cycles. Unlike SrTiO3, the symmetry of the (111)pc plane is broken in case of NGO, which removes the degeneracy of the monoclinic domains, resulting associated single AFM domain with spin-cycloid along [1-10]. Also, the BFO film on NGO carries the orthorhombic distortion which helps in selecting a preferred path over others during electric field switching and thus, reducing the formation of charged domain wall which leads to robust and deterministic polarization reversal over many cycles. Thus, our study opens an avenue to explore (111) single domain BFO films toward prospective device applications.

* CBE acknowledges support for this research through the Gordon and Betty Moore Foundation’s EPiQS Initiative, Grant GBMF9065 and a Vannevar Bush Faculty Fellowship (ONR N00014-20-1-2844).

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Presenters

  • Pratap Pal

    University of Wisconsin-Madison, Department of Materials Science and Engineering, University of Wisconsin-Madison, Wisconsin 53706, USA

Authors

  • Pratap Pal

    University of Wisconsin-Madison, Department of Materials Science and Engineering, University of Wisconsin-Madison, Wisconsin 53706, USA

  • Jonathon L Schad

    Department of Materials Science and Engineering, University of Wisconsin-Madison, Wisconsin 53706, USA

  • Anuradha M Vibhakar

    Diamond Light Source Ltd, Diamond Light Source Ltd, Harwell Science and Innovation Campus,Didcot, Oxford shire, OX11 0DE, United Kingdom.

  • Roger D Johnson

    University College London, Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom.

  • Paolo G Paolo G. Radaelli

    Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom

  • Chang-Beom Eom

    University of Wisconsin-Madison, Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA, University of wisconsin-madison, Department of Materials Science and Engineering, University of Wisconsin-Madison, Wisconsin 53706, USA