Polarization Selective Magnetic Vortex Dynamics and Core Reversal in Rotating Magnetic Fields

Curcic, Michael; Waeyenberge, Bartel Van; Vansteenkiste, Arne; Weigand, Markus; Sackmann, V.; Stoll, Hermann; Fähnle, M.; Tyliszczak, Tolek; Woltersdorf, Georg; Back, Christian; Schütz, Gisela

doi:10.1103/physrevlett.101.197204

Cited by 143 publications

(128 citation statements)

References 23 publications

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“…A priori, one would expect the energy of the four states to be degenerate. A non-degeneracy would not only constitute an unconventional physical phenomenon at the nanoscale but could also lead to potentially interesting applications of magnetic vortices with regard to magnetic sensor or logic elements 16,17 . Owing to the lack of experimental techniques enabling simultaneous imaging of in-plane (c) and out-of-plane (p) magnetic components in nanopatterned structures, most of the experiments on magnetic vortices reported so far have focussed on either the chirality or polarity 9,15 .…”

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confidence: 99%

Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk

et al. 2012

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The magnetic vortex in nanopatterned elements is currently attracting enormous interest. A priori, one would assume that the formation of magnetic vortex states should exhibit a perfect symmetry, because the magnetic vortex has four degenerate states. Here we show the first direct observation of an asymmetric phenomenon in the formation process of vortex states in a permalloy nanodisk using high-resolution full-field magnetic transmission soft X-ray microscopy. micromagnetic simulations confirm that the intrinsic Dzyaloshinskii-moriya interaction, which arises from the spin-orbit coupling due to the lack of inversion symmetry near the disk surface, as well as surface-related extrinsic factors, is decisive for the asymmetric formation of vortex states.

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confidence: 99%

Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk

et al. 2012

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“…Since the vortex polarity is very stable and well controllable, such structures may be used in the future for information storage and data processing devices. It has been demonstrated that the vortex core polarity can be dynamically reversed by exciting one of the eigenmodes of the vortex structure, i.e., the gyrotropic mode [1][2][3][4] or dipolar spin-wave modes. [5][6][7] For the vortex gyrotropic mode G 0 , the vortex core performs a translational motion with frequencies in the range of 100 MHz to 1 GHz (depending on the disk dimensions and the material of the disk).…”

Section: Introductionmentioning

confidence: 99%

“…Due to their symmetry, dipolar spin-wave modes with azimuthal mode numbers jmj ¼ 1 can be efficiently excited by magnetic in-plane fields. To achieve vortex core reversal, dynamical external magnetic in-plane fields 1,2,[5][6][7]11 or dynamical spin-polarized currents 3 have been used. Unidirectional switching, which is a prerequisite for data storage applications, is possible by using rotating in-plane fields with the frequency and sense of rotation tuned to the gyrotropic eigenmode G 0 , 2 or to azimuthal spin waves.…”

Section: Introductionmentioning

confidence: 99%

Spin wave mediated unidirectional vortex core reversal by two orthogonal monopolar field pulses: The essential role of three-dimensional magnetization dynamics

Noske

Stoll

Fähnle

et al. 2016

Journal of Applied Physics

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Scanning transmission x-ray microscopy is employed to investigate experimentally the reversal of the magnetic vortex core polarity in cylindrical Ni81Fe19 nanodisks triggered by two orthogonal monopolar magnetic field pulses with peak amplitude B0, pulse length τ=60 ps, and delay time Δt in the range from −400 ps to +400 ps between the two pulses. The two pulses are oriented in-plane in the x- and y-directions. We have experimentally studied vortex core reversal as a function of B0 and Δt. The resulting phase diagram shows large regions of unidirectional vortex core switching where the switching threshold is modulated due to resonant amplification of azimuthal spin waves. The switching behavior changes dramatically depending on whether the first pulse is applied in the x- or the y-direction. This asymmetry can be reproduced by three-dimensional micromagnetic simulations but not by two-dimensional simulations. This behavior demonstrates that in contrast to the previous experiments on vortex core reversal, the three-dimensionality in the dynamics is essential here.

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“…Later, unidirectional vortex core reversal by excitation with in-plane rotating magnetic fields has been achieved. 4,5 In this letter, we present how to measure vortex core reversal by varying the excitation frequency and amplitude with a commercial table-top Magneto-Optical Kerr Effect (MOKE) microscope with a lateral resolution of 2 lm combined with a highly sensitive lock-in-technique. With this technique, vortex core reversal can be detected and, in particular, the switching probability can be determined highly precise compared to other methods.…”

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confidence: 99%

Switching probabilities of magnetic vortex core reversal studied by table top magneto optic Kerr microscopy

Dieterle

Gangwar

Gräfe

et al. 2016

Applied Physics Letters

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We have studied vortex core reversal in a single submicron Permalloy disk by polar Kerr microscopy. A sophisticated lock-in-technique based on repetitive switching of the magnetic vortex core and a continuous calibration allows for a reliable determination of the switching probability. This highly sensitive method facilitates the detection of a change in the magnetic moment of the tiny magnetic vortex core which is about 1.5 × 10−17 A m2. We have investigated vortex core switching caused by excitation of the vortex core gyromode with varying frequencies and amplitudes. The frequency range in which switching occurs was found to broaden with increasing excitation amplitude, whereby the highest frequency in this range shifts stronger to higher frequencies than the lowest frequency to lower frequencies. The experimental results are in good agreement with micromagnetic simulations.

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Polarization Selective Magnetic Vortex Dynamics and Core Reversal in Rotating Magnetic Fields

Cited by 143 publications

References 23 publications

Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk

Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk

Spin wave mediated unidirectional vortex core reversal by two orthogonal monopolar field pulses: The essential role of three-dimensional magnetization dynamics

Switching probabilities of magnetic vortex core reversal studied by table top magneto optic Kerr microscopy

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