title: Deterministic switching of ferromagnetism at room temperature using an electric field.
abstract: The technological appeal of multiferroics is the ability to control magnetism with electric field. For devices to be useful, such control must be achieved at room temperature. The only single-phase multiferroic material exhibiting unambiguous magnetoelectric coupling at room temperature is BiFeO3 (refs 4 and 5). Its weak ferromagnetism arises from the canting of the antiferromagnetically aligned spins by the Dzyaloshinskii-Moriya (DM) interaction. Prior theory considered the symmetry of the thermodynamic ground state and concluded that direct 180-degree switching of the DM vector by the ferroelectric polarization was forbidden. Instead, we examined the kinetics of the switching process, something not considered previously in theoretical work. Here we show a deterministic reversal of the DM vector and canted moment using an electric field at room temperature. First-principles calculations reveal that the switching kinetics favours a two-step switching process. In each step the DM vector and polarization are coupled and 180-degree deterministic switching of magnetization hence becomes possible, in agreement with experimental observation. We exploit this switching to demonstrate energy-efficient control of a spin-valve device at room temperature. The energy per unit area required is approximately an order of magnitude less than that needed for spin-transfer torque switching. Given that the DM interaction is fundamental to single-phase multiferroics and magnetoelectrics, our results suggest ways to engineer magnetoelectric switching and tailor technologically pertinent functionality for nanometre-scale, low-energy-consumption, non-volatile magnetoelectronics.
authors.affiliation: Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Heron
authors.affiliation: Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Bosse
authors.affiliation: Department of Physics, Durham University, Durham DH1 3LE, UK.
authors.forename: Q
authors.initials: Q
authors.lastname: He
authors.affiliation: 1] Department of Physics, University of California, Berkeley, California 94720, USA [2] School of Materials Science and Engineering, and State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4 10, 8093 Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Trassin
authors.affiliation: Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: L
authors.initials: L
authors.lastname: Ye
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Clarkson
authors.affiliation: Department of Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, Berkeley, California 94720, USA.
authors.forename: S
authors.initials: S
authors.lastname: Salahuddin
authors.affiliation: 1] Department of Physics, Cornell University, Ithaca, New York 14853, USA [2] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Ralph
authors.affiliation: 1] Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA [2] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Schlom
authors.affiliation: Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Iñiguez
authors.affiliation: 1] Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269, USA [2] Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: B D
authors.initials: BD
authors.lastname: Huey
authors.affiliation: 1] Department of Physics, University of California, Berkeley, California 94720, USA [2] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [3] Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: R
authors.initials: R
authors.lastname: Ramesh