title: Ultrafast optical parametric pumping of magnetization reorientation and precessional dynamics in DyFe2/YFe2 exchange springs.
abstract: The magnetization dynamics of a wound [DyFe(2)(20  Å)/YFe(2)(80  Å)](×40) exchange spring multilayer have been explored in optical pump probe experiments. Ultrafast optical heating was used to modify the magnetic parameters of the multilayer, while the time resolved magneto-optical Kerr effect was used to probe its response. Although the probe signal is dominated by precession and winding of the exchange spring within the soft YFe(2) layer, reorientation of the DyFe(2) hard-layer magnetization is detected on time scales less than 100 ps. Micromagnetic simulations reproduce the main features of the experimental data and indicate a dramatic optically induced reduction of the hard-layer anisotropy. The results establish the feasibility of switching a spring system by means of parametric excitation.
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom.
authors.forename: L R
authors.initials: LR
authors.lastname: Shelford
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom.
authors.forename: U
authors.initials: U
authors.lastname: Al-Jarah
authors.affiliation: School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom.
authors.forename: P A J
authors.initials: PA
authors.lastname: de Groot
authors.affiliation: School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom.
authors.forename: G J
authors.initials: GJ
authors.lastname: Bowden
authors.affiliation: Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: R C C
authors.initials: RC
authors.lastname: Ward
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom.
authors.forename: R J
authors.initials: RJ
authors.lastname: Hicken