Picosecond pulsed magnetic fields for studies of ultrafast magnetic phenomena

Freeman, M. R.; Ruf, R.; Gambino, R. J.

doi:10.1109/20.278964

Cited by 60 publications

(34 citation statements)

References 6 publications

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“…To isolate the oscillatory part of the signal, this background was subtracted from the time-resolved signals measured at lower field values. 5 However, the form of the pulsed field background observed in the experiments was not known exactly. Therefore, the background cannot be completely removed which results in a large peak in the experimental spectra below 1 GHz.…”

Section: A Time-resolved Signalsmentioning

confidence: 99%

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Time-resolved investigation of magnetization dynamics of arrays of nonellipsoidal nanomagnets with nonuniform ground states

et al. 2008

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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 simulations of model arrays in order to understand the nonuniform precessional dynamics within the elements. In the experimental spectra acquired from an element of length of 236 nm and thickness of 13.6 nm, two branches of excited modes were observed to coexist above a particular bias field. Below this so-called crossover field, the higher frequency branch was observed to vanish. Micromagnetic simulations and Fourier imaging revealed that modes from the higher frequency branch had large amplitude at the center of the element where the effective field was parallel to the bias field and the static magnetization. Modes from the lower frequency branch had large amplitude near the edges of the element perpendicular to the bias field. The simulations revealed significant canting of the static magnetization and effective field away from the direction of the bias field in the edge regions. For the smallest element sizes and/or at low bias field values, the effective field was found to become antiparallel to the static magnetization. The simulations revealed that the majority of the modes were delocalized with finite amplitude throughout the element while the spatial character of a mode was found to be correlated with the spatial variation in the total effective field and the static magnetization state. The simulations also revealed that the frequencies of the edge modes are strongly affected by the spatial distribution of the static magnetization state both within an element and within its nearest neighbors. Furthermore, the simulations suggest that collective modes may be supported in arrays of interacting nanomagnets, which act as magnonic crystals.

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Section: A Time-resolved Signalsmentioning

confidence: 99%

“…3 Experiments have been performed in which magnetization precession has been induced by harmonic 4 or pulsed 5 magnetic fields, ultrashort optical pulses, 6 and a dc spin polarized current. 7 In the majority of such studies, the samples were essentially unbounded and the ground-state magnetization was virtually uniform.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved investigation of magnetization dynamics of arrays of nonellipsoidal nanomagnets with nonuniform ground states

et al. 2008

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“…The modern magneto-optic technique allowing to investigate flux patterns with time resolution on the order of ≈ 100 ps [5,6] stimulated quite a few experimental and theoretical studies of flux front patterns arising in a process of smooth flux penetration [7] as well as in a process of critical state instability development in superconducting films in a transversal magnetic field. Different scenarios are considered resulting in a variety of flux patterns, e.g., magnetic turbulence [8,9], kinetic flux front roughening [10], magnetic micro avalanches [11,12], flux dendrites [13,14,15,16,17], thermomagnetic fingering [18], bending of flux-antiflux interface [19,20], and flux front corrugation [21].…”

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confidence: 99%

Ultrafast magnetic flux dendrite propagation into thin superconducting films

et al. 2005

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We suggest a new theoretical approach describing the velocity of magnetic flux dendrite penetration into thin superconducting films. The key assumptions for this approach are based upon experimental observations. We treat a dendrite tip motion as a propagating flux jump instability. Two different regimes of dendrite propagation are found: A fast initial stage is followed by a slow stage, which sets in as soon as a dendrite enters into the vortex-free region. We find that the dendrite velocity is inversely proportional to the sample thickness. The theoretical results and experimental data obtained by a magneto-optic pump-probe technique are compared and excellent agreement between the calculations and measurements is found.

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“…By varying the time delay of the probe pulse with respect to the pump, the temporal evolution of the magnetic response of the sample can be mapped by recording the MOKE signal at each time delay. The magnetization dynamics may be excited either directly using an intense laser pulse [27], or by a time-varying magnetic field that is either triggered by or synchronized to the laser [28]. The use of a sub-100 fs laser pulse as a pump leads to rapid heating of the ferromagnetic sample near to, or above, the Curie temperature, resulting in an ultrafast demagnetization on femtosecond time scales [27].…”

Section: Dynamical Phenomena and Measurement Techniquesmentioning

confidence: 99%

Ultrafast magnetization dynamics of spintronic nanostructures

Keatley

Kruglyak

Gangmei

et al. 2011

Phil. Trans. R. Soc. A.

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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 the two decades since the discovery of giant magnetoresistance and the prediction of spin-transfer torque are discussed, along with the plethora of new experimental techniques developed to make measurements on shorter length and time scales. Particular consideration is given to time-resolved measurements of the magneto-optical Kerr effect, and it is shown how a succession of studies performed with this technique has led to an improved understanding of the dynamics of nanoscale magnets. The dynamics can be surprisingly rich and complicated, with the latest studies of individual nanoscale elements showing that the dependence of the resonant mode spectrum upon the physical structure is still not well understood. Finally, the article surveys the prospects for development of high-frequency spintronic devices and highlights areas in which further study of fundamental properties will be required within the coming decade.

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Picosecond pulsed magnetic fields for studies of ultrafast magnetic phenomena

Cited by 60 publications

References 6 publications

Time-resolved investigation of magnetization dynamics of arrays of nonellipsoidal nanomagnets with nonuniform ground states

Time-resolved investigation of magnetization dynamics of arrays of nonellipsoidal nanomagnets with nonuniform ground states

Ultrafast magnetic flux dendrite propagation into thin superconducting films

Ultrafast magnetization dynamics of spintronic nanostructures

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