title: Spin pumping in ferromagnet-topological insulator-ferromagnet heterostructures.
abstract: Topological insulators (TIs) are enticing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. However, a means to interact with and exploit the topological surface state remains elusive. Here, we report a study of spin pumping at the TI-ferromagnet interface, investigating spin transfer dynamics in a spin-valve like structure using element specific time-resolved x-ray magnetic circular dichroism, and ferromagnetic resonance. Gilbert damping increases approximately linearly with increasing TI thickness, indicating efficient behaviour as a spin sink. However, layer-resolved measurements suggest that a dynamic coupling is limited. These results shed new light on the spin dynamics of this novel material class, and suggest great potential for TIs in spintronic devices, through their novel magnetodynamics that persist even up to room temperature.
authors.affiliation: 1] Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, United Kingdom [2] Magnetic Spectroscopy Group, Diamond Light Source, Didcot, OX11 0DE, 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: Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, United Kingdom.
authors.forename: L J
authors.initials: LJ
authors.lastname: Collins-McIntyre
authors.affiliation: Magnetic Spectroscopy Group, Diamond Light Source, Didcot, OX11 0DE, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: van der Laan
authors.affiliation: Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, United Kingdom.
authors.forename: T
authors.initials: T
authors.lastname: Hesjedal