Now showing items 1-19 of 19

  • Direct excitation of propagating spin waves by focused ultrashort optical pulses 

    Au, Y.; Dvornik, Mykola; Davison, T.; Ahmad, E.; Keatley, Paul Steven; Vansteenkiste, A.; Van Waeyenberge, B.; Kruglyak, V.V. (American Physical Society, 2013)
    An all-optical experiment long utilized to image phonons excited by ultrashort optical pulses has been applied to a magnetic sample. In addition to circular ripples due to surface acoustic waves, we observe an X-shaped ...
  • Domain-wall pinning, nonadiabatic spin-transfer torque, and spin-current polarization in permalloy wires doped with vanadium 

    Lepadatu, S.; Claydon, J.S.; Kinane, C.J.; Charlton, T.R.; Langridge, Sean; Potenza, A.; Dhesi, Sarnjeet S.; Keatley, Paul Steven; Hicken, R.J.; Hickey, B.J.; Marrows, C.H. (American Physical Society, 2010)
    Using pulsed-current measurements we investigate the domain-wall depinning via spin-transfer torque from pinning potentials in V-doped Ni80Fe20 wires. The domain-wall depinning boundary, showing the variation of threshold ...
  • Dynamic configurational anisotropy in nanomagnets 

    Kruglyak, V.V.; Keatley, Paul Steven; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Physical Society, 2007)
    The angular dependence of ultrafast magnetization dynamics in nanomagnets of square shape was studied by magneto-optical pump-probe measurements. In agreement with micromagnetic simulations, both the number of precessional ...
  • Evidence of local moment formation in Co-based Heusler alloys 

    Telling, N.D.; Keatley, Paul Steven; van der Laan, Gerrit; Hicken, R.J.; Arenholz, E.; Sakuraba, Y.; Oogane, M.; Ando, Y.; Takanashi, K.; Sakuma, A.; Miyazaki, T. (American Physical Society, 2008)
    We examine the formation of local moments in Heusler alloys of the composition Co(2)MnZ (where Z=Si or Al) using the combined techniques of x-ray magnetic circular and linear dichroism. The existence of local moments in ...
  • Excitation and Imaging of Precessional Modes in Soft-Magnetic Squares 

    Neudert, A.; Keatley, Paul Steven; Kruglyak, V.V.; McCord, Jeffrey; Hicken, R.J. (Institute of Electrical and Electronics Engineers (IEEE), 2008)
    We investigated the high-frequency modes of 40 mum wide, 160 nm thick Fe 70Co8B12Si10 squares using time-resolved scanning Kerr microscopy. Two modes were identified using pulsed field excitation while the spatial character ...
  • Excitation of propagating spin waves with global uniform microwave fields 

    Au, Y.; Davison, T.; Ahmad, E.; Keatley, Paul Steven; Hicken, R.J.; Kruglyak, V.V. (American Institute of Physics, 2011)
    We demonstrate a magnonic architecture that converts global free-space uniform microwaves into spin waves propagating in a stripe magnonic waveguide. The architecture is based upon dispersion mismatch between the narrow ...
  • Ferrite-filled cavities for compact planar resonators 

    Keatley, Paul Steven; Durrant, C.J.; Berry, S.J.; Sirotkin, Evgeny; Hibbins, Alastair P.; Hicken, R.J. (American Institute of Physics (AIP) -, 2014)
    Sub-wavelength metallic planar cavities, closed at one end, have been constructed by wrapping aluminium foil around teflon or ferrite slabs. Finite cavity width perturbs the fundamental cavity mode frequency of ferrite-filled ...
  • Imaging collective magnonic modes in 2D arrays of magnetic nanoelements 

    Kruglyak, V.V.; Keatley, Paul Steven; Neudert, A.; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Physical Society, 2010)
    We have used time resolved scanning Kerr microscopy to image collective spin wave modes within a 2D array of magnetic nanoelements. Long wavelength spin waves are confined within the array as if it was a continuous element ...
  • Imaging small-amplitude magnetization dynamics in a longitudinally magnetized microwire 

    Kruglyak, V.V.; Keatley, Paul Steven; Neudert, A.; Delchini, M.; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Physical Society, 2008)
    We have used time-resolved scanning Kerr microscopy to study spin waves in a magnetic microwire subjected to a bias magnetic field applied parallel to its long axis. The spin-wave spectra obtained from different points ...
  • Interfacial structure and half-metallic ferromagnetism in Co2MnSi-based magnetic tunnel junctions 

    Telling, N.D.; Keatley, Paul Steven; van der Laan, Gerrit; Hicken, R.J.; Arenholz, E.; Sakuraba, Y.; Oogane, M.; Ando, Y.; Miyazaki, T. (American Physical Society, 2006)
    X-ray absorption (XAS) and x-ray magnetic circular dichroism (XMCD) techniques are utilized to explore the ferromagnetic/barrier interface in Co2MnSi full Heusler alloy magnetic tunnel junctions. Structural and magnetic ...
  • Large amplitude magnetization dynamics and the suppression of edge modes in a single nanomagnet 

    Keatley, Paul Steven; Gangmei, Prim; Dvornik, Mykola; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Institute of Physics, 2011)
    Large amplitude magnetization dynamics of a single square nanomagnet have been studied by time-resolved Kerr microscopy. Experimental spectra revealed that only a single mode was excited for all bias field values. Micromagnetic ...
  • Phase-resolved x-ray ferromagnetic resonance measurements in fluorescence yield 

    Marcham, Max K.; Keatley, Paul Steven; Neudert, A.; Hicken, R.J.; Cavill, Stuart A.; Shelford, L.R.; van der Laan, Gerrit; Telling, N.D.; Childress, J.R.; Katine, J.A.; Shafer, P.; Arenholz, E. (American Institute of Physics, 2011)
    Phase-resolved x-ray ferromagnetic resonance (XFMR) has been measured in fluorescence yield, extending the application of XFMR to opaque samples on opaque substrates. Magnetization dynamics were excited in a Co50Fe50(0.7 ...
  • Temperature dependence of the interface moments in Co2MnSi thin films 

    Telling, N.D.; Keatley, Paul Steven; Shelford, L.R.; Arenholz, E.; van der Laan, Gerrit; Hicken, R.J.; Sakuraba, Y.; Tsunegi, S.; Oogane, M.; Ando, Y.; Takanashi, K.; Miyazaki, T. (American Institute of Physics, 2008-05-12)
    X-ray magnetic circular dichroism (XMCD) is utilized to explore the temperature dependence of the interface moments in Co2MnSi (CMS) thin films capped with aluminum. By increasing the thickness of the capping layer, we ...
  • Time resolved studies of edge modes in magnetic nanoelements (invited) 

    Kruglyak, V.V.; Keatley, Paul Steven; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Institute of Physics, 2006)
    Micromagnetic simulations have been performed to investigate the frequencies and relative amplitudes of resonant magnetic modes within nanomagnetic elements of varying size that have been previously studied by time resolved ...
  • Time- and vector-resolved Kerr microscopy of hard disk writers 

    Gangmei, Prim; Keatley, Paul Steven; Yu, W.; Hicken, R.J.; Gubbins, M.A.; Czoschke, P.J.; Lopusnik, R. (American Institute of Physics, 2011)
    Time-resolved scanning Kerr microscopy has been used to make wafer level measurements of magnetization dynamics within the yoke and pole piece of partially built hard disk writer structures. Three Cartesian components of ...
  • Time- and vector-resolved magneto-optical Kerr effect measurements of large angle precessional reorientation in a 2×2 μ m2 ferromagnet 

    Keatley, Paul Steven; Kruglyak, V.V.; Neudert, A.; Delchini, M.; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Institute of Physics, 2009)
    The precessional dynamics of a 2×2 μm2 CoFe/NiFe (4.6 nm) element stimulated by an in-plane pulsed magnetic field have been investigated using time- and vector-resolved Kerr microscopy measurements and micromagnetic ...
  • Time-resolved investigation of magnetization dynamics of arrays of nonellipsoidal nanomagnets with nonuniform ground states 

    Keatley, Paul Steven; Kruglyak, V.V.; Neudert, A.; Galaktionov, E.A.; Hicken, R.J.; Childress, J.R.; Katine, J.A. (American Physical Society, 2008)
    Time-resolved scanning Kerr microscopy measurements have been performed upon arrays of square ferromagnetic nanoelements of different sizes and for a range of bias fields. The experimental results were compared to micromagnetic ...
  • Ultrafast magnetization dynamics of spintronic nanostructures 

    Keatley, Paul Steven; Kruglyak, V.V.; Gangmei, Prim; Hicken, R.J. (Royal Society, 2011)
    The ultrafast (sub-nanosecond) magnetization dynamics of ferromagnetic thin films and elements that find application in spintronic devices is reviewed. The major advances in the understanding of magnetization dynamics in ...
  • Use of microscale coplanar striplines with indium tin oxide windows in optical ferromagnetic resonance measurements 

    Keatley, Paul Steven; Kruglyak, V.V.; Barman, A.; Ladak, S.; Hicken, R.J.; Scott, J.; Rahman, M. (American Institute of Physics, 2005)
    It is shown that a coplanar stripline structure containing indium tin oxide windows can be used to perform optical ferromagnetic resonance measurements on a sample grown on an opaque substrate, using a pulsed magnetic field ...