title: X-ray Detection of Transient Magnetic Moments Induced by a Spin Current in Cu.
abstract: We have used a MHz lock-in x-ray spectromicroscopy technique to directly detect changes in magnetic moment of Cu due to spin injection from an adjacent Co layer. The elemental and chemical specificity of x rays allows us to distinguish two spin current induced effects. We detect the creation of transient magnetic moments of 3×10^{-5}μ_{B} on Cu atoms within the bulk of the 28 nm thick Cu film due to spin accumulation. The moment value is compared to predictions by Mott's two current model. We also observe that the hybridization induced existing magnetic moments at the Cu interface atoms are transiently increased by about 10% or 4×10^{-3}μ_{B} per atom. This reveals the dominance of spin-torque alignment over Joule heat induced disorder of the interfacial Cu moments during current flow.
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, USA.
authors.forename: R
authors.initials: R
authors.lastname: Kukreja
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305, USA.
authors.forename: S
authors.initials: S
authors.lastname: Bonetti
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Physics Department, New York University, 4 Washington Place, New York, New York 10003, USA.
authors.forename: D
authors.initials: D
authors.lastname: Backes
authors.affiliation: Laboratorium für Festkörperphysik, ETH Zürich, HPF C 5, Otto-Stern-Weg 1, Zürich 8093, Switzerland.
authors.forename: Y
authors.initials: Y
authors.lastname: Acremann
authors.affiliation: HGST, a Western Digital Company, 3403 Yerba Buena Road, San Jose, California 95135, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Katine
authors.affiliation: Physics Department, New York University, 4 Washington Place, New York, New York 10003, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Kent
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Dürr
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ohldag
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Stöhr