title: Probing electric field control of magnetism using ferromagnetic resonance.
abstract: Exchange coupled CoFe/BiFeO3 thin-film heterostructures show great promise for power-efficient electric field-induced 180° magnetization switching. However, the coupling mechanism and precise qualification of the exchange coupling in CoFe/BiFeO3 heterostructures have been elusive. Here we show direct evidence for electric field control of the magnetic state in exchange coupled CoFe/BiFeO3 through electric field-dependent ferromagnetic resonance spectroscopy and nanoscale spatially resolved magnetic imaging. Scanning electron microscopy with polarization analysis images reveal the coupling of the magnetization in the CoFe layer to the canted moment in the BiFeO3 layer. Electric field-dependent ferromagnetic resonance measurements quantify the exchange coupling strength and reveal that the CoFe magnetization is directly and reversibly modulated by the applied electric field through a ~180° switching of the canted moment in BiFeO3. This constitutes an important step towards robust repeatable and non-volatile voltage-induced 180° magnetization switching in thin-film multiferroic heterostructures and tunable RF/microwave devices.
authors: Electric and Computer Engineering Department, Northeastern University, Boston, Massachusetts 02115, USA.
authors: Ziyao
authors: Z
authors: Zhou
authors: Department of Physics, University of California, Berkeley, California 94720, USA.
authors: Morgan
authors: M
authors: Trassin
authors: Department of Physics, University of California, Berkeley, California 94720, USA.
authors: Ya
authors: Y
authors: Gao
authors: Electric and Computer Engineering Department, Northeastern University, Boston, Massachusetts 02115, USA.
authors: Yuan
authors: Y
authors: Gao
authors: Department of Electrical and Computer Engineering, University of California, Berkeley, California 94720, USA.
authors: Diana
authors: D
authors: Qiu
authors: Department of Physics, University of California, Berkeley, California 94720, USA.
authors: Khalid
authors: K
authors: Ashraf
authors: Electric and Computer Engineering Department, Northeastern University, Boston, Massachusetts 02115, USA.
authors: Tianxiang
authors: T
authors: Nan
authors: Electric and Computer Engineering Department, Northeastern University, Boston, Massachusetts 02115, USA.
authors: Xi
authors: X
authors: Yang
authors: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors: S R
authors: SR
authors: Bowden
authors: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors: D T
authors: DT
authors: Pierce
authors: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors: M D
authors: MD
authors: Stiles
authors: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors: J
authors: J
authors: Unguris
authors: Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education &International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China.
authors: Ming
authors: M
authors: Liu
authors: Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, USA.
authors: Brandon M
authors: BM
authors: Howe
authors: Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, USA.
authors: Gail J
authors: GJ
authors: Brown
authors: Department of Electrical and Computer Engineering, University of California, Berkeley, California 94720, USA.
authors: S
authors: S
authors: Salahuddin
authors: Department of Physics, University of California, Berkeley, California 94720, USA.
authors: R
authors: R
authors: Ramesh
authors: Electric and Computer Engineering Department, Northeastern University, Boston, Massachusetts 02115, USA.
authors: Nian X
authors: NX
authors: Sun