title: Electric Field Control of Interfacial Ferromagnetism in CaMnO_{3}/CaRuO_{3} Heterostructures.
abstract: New mechanisms for achieving direct electric field control of ferromagnetism are highly desirable in the development of functional magnetic interfaces. To that end, we have probed the electric field dependence of the emergent ferromagnetic layer at CaRuO_{3}/CaMnO_{3} interfaces in bilayers fabricated on SrTiO_{3}. Using polarized neutron reflectometry, we are able to detect the ferromagnetic signal arising from a single atomic monolayer of CaMnO_{3}, manifested as a spin asymmetry in the reflectivity. We find that the application of an electric field of 600 kV/m across the bilayer induces a significant increase in this spin asymmetry. Modeling of the reflectivity suggests that this increase corresponds to a transition from canted antiferromagnetism to full ferromagnetic alignment of the Mn^{4+} ions at the interface. This increase from 1 μ_{B} to 2.5-3.0 μ_{B} per Mn is indicative of a strong magnetoelectric coupling effect, and such direct electric field control of the magnetization at an interface has significant potential for spintronic applications.
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Grutter
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kirby
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.|Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Gray
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.|Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Flint
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.|Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: U S
authors.initials: US
authors.lastname: Alaan
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Borchers