title: Anisotropic Absorption of Pure Spin Currents.
abstract: Spin transfer in magnetic multilayers offers the possibility of ultrafast, low-power device operation. We report a study of spin pumping in spin valves, demonstrating that a strong anisotropy of spin pumping from the source layer can be induced by an angular dependence of the total Gilbert damping parameter, α, in the spin sink layer. Using lab- and synchrotron-based ferromagnetic resonance, we show that an in-plane variation of damping in a crystalline Co_{50}Fe_{50} layer leads to an anisotropic α in a polycrystalline Ni_{81}Fe_{19} layer. This anisotropy is suppressed above the spin diffusion length in Cr, which is found to be 8 nm, and is independent of static exchange coupling in the spin valve. These results offer a valuable insight into the transmission and absorption of spin currents, and a mechanism by which enhanced spin torques and angular control may be realized for next-generation spintronic devices.
authors.affiliation: Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom.|Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom.
authors.forename: A A
authors.initials: AA
authors.lastname: Baker
authors.affiliation: Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom.
authors.forename: A I
authors.initials: AI
authors.lastname: Figueroa
authors.affiliation: Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom.|Department of Physics, University of York, York YO10 5DD, United Kingdom.
authors.forename: C J
authors.initials: CJ
authors.lastname: Love
authors.affiliation: Department of Physics, University of York, York YO10 5DD, United Kingdom.|Diamond Light Source, Didcot OX11 0DE, United Kingdom.
authors.forename: S A
authors.initials: SA
authors.lastname: Cavill
authors.affiliation: Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom.|Diamond Light Source, Didcot OX11 0DE, United Kingdom.
authors.forename: T
authors.initials: T
authors.lastname: Hesjedal
authors.affiliation: Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: van der Laan