Publication Type:Journal Article
Source:Nature, Nature Publishing Group, Volume 516, Number 7531, p.370-373 (2014)
Keywords:Article, electric conductivity, electric field, Electrochemistry, kinetics, magnetic field, Magnetism, Magnetization, Polarization, priority journal, reaction kinetics, room temperature, rotation, Theoretical study, thermodynamics, torque
The technological appeal of multiferroics is the ability to control magnetism with electric field1-3. For devices to be useful, such control must be achieved at room temperature. The only single-phase multiferroicmaterial exhibiting unambiguousmagnetoelectric coupling at room temperature is BiFeO3 (refs 4 and 5). Its weak ferromagnetismarises fromthe canting of the antiferromagnetically aligned spins by the Dzyaloshinskii-Moriya (DM) interaction6-9. Prior theory considered the symmetry of the thermodynamic ground state and concluded that direct 180-degree switching of theDMvector by the ferroelectric polarization was forbidden10,11. Instead, we examined the kinetics of the switching process, something not considered previously in theoretical work10-12. Here we show a deterministic reversal of theDMvector and cantedmoment using an electric field at roomtemperature. First-principles calculations reveal that the switching kinetics favours a two-step switching process. In each step the DMvector 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 switching13,14.Given that theDMinteraction is fundamental to singlephasemultiferroics andmagnetoelectrics3,9, our results suggest ways to engineermagnetoelectric switching and tailor technologically pertinent functionality for nanometre-scale, low-energy-consumption, non-volatile magnetoelectronics. © 2014 Macmillan Publishers Limited.
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