title: Room Temperature Magnetically Ordered Polar Corundum GaFeO3Displaying Magnetoelectric Coupling.
abstract: The polar corundum structure type offers a route to new room temperature multiferroic materials, as the partial LiNbO3-type cation ordering that breaks inversion symmetry may be combined with long-range magnetic ordering of high spin d5cations above room temperature in the AFeO3system. We report the synthesis of a polar corundum GaFeO3by a high-pressure, high-temperature route and demonstrate that its polarity arises from partial LiNbO3-type cation ordering by complementary use of neutron, X-ray, and electron diffraction methods. In situ neutron diffraction shows that the polar corundum forms directly from AlFeO3-type GaFeO3under the synthesis conditions. The A3+/Fe3+cations are shown to be more ordered in polar corundum GaFeO3than in isostructural ScFeO3. This is explained by DFT calculations which indicate that the extent of ordering is dependent on the configurational entropy available to each system at the very different synthesis temperatures required to form their corundum structures. Polar corundum GaFeO3exhibits weak ferromagnetism at room temperature that arises from its Fe2O3-like magnetic ordering, which persists to a temperature of 408 K. We demonstrate that the polarity and magnetization are coupled in this system with a measured linear magnetoelectric coupling coefficient of 0.057 ps/m. Such coupling is a prerequisite for potential applications of polar corundum materials in multiferroic/magnetoelectric devices.
authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
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authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
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authors.initials: MJ
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authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
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authors.affiliation: Department of Chemistry, University College London , Gower Street, London WC1E 6BT, United Kingdom.
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authors.identifier: 0000-0003-1574-7476
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authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
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authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
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authors.affiliation: Centre for Materials and Structures, School of Engineering, University of Liverpool , Liverpool L69 3GH, United Kingdom.
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authors.identifier: 0000-0002-6384-6690
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authors.affiliation: EMAT, University of Antwerp , Groenenborgerlaan 171, 2020 Antwerp, Belgium.|Skoltech Center for Electrochemical Energy Storage, Skolkovo Institute of Science and Technology , 143026 Moscow, Russian Federation.
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authors.initials: AM
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authors.affiliation: ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom.
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authors.affiliation: ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom.
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authors.initials: RI
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authors.affiliation: Diamond Light Source, Diamond House , Harwell Oxford, Didcot, Oxfordshire OX11 0DE, United Kingdom.
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authors.initials: CA
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authors.affiliation: Diamond Light Source, Diamond House , Harwell Oxford, Didcot, Oxfordshire OX11 0DE, United Kingdom.
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authors.initials: SJ
authors.lastname: Day
authors.affiliation: Department of Chemistry, University College London , Gower Street, London WC1E 6BT, United Kingdom.
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authors.lastname: Slater
authors.affiliation: Department of Chemistry, University College London , Gower Street, London WC1E 6BT, United Kingdom.
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authors.initials: F
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authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
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authors.initials: JB
authors.lastname: Claridge
authors.affiliation: Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 7ZD, United Kingdom.
authors.forename: Matthew J
authors.identifier: 0000-0002-1910-2483
authors.initials: MJ
authors.lastname: Rosseinsky