Ultrafast magnetization dynamics in a nanoscale three-dimensional cobalt tetrapod structure

Ferromagnetic antidot arrays have emerged as a system of tremendous interest due to their interesting spin configuration and dynamics as well as their potential applications in magnetic storage, memory, logic, communications and sensing devices. Here, we report experimental and numerical investigation of ultrafast magnetization dynamics in a new type of antidot lattice in the form of triangular-shaped Ni80Fe20 antidots arranged in a hexagonal array. Time-resolved magneto-optical Kerr effect and micromagnetic simulations have been exploited to study the magnetization precession and spin-wave modes of the antidot lattice with varying lattice constant and in-plane orientation of the bias-magnetic field. A remarkable variation in the spin-wave modes with the orientation of in-plane bias magnetic field is found to be associated with the conversion of extended spin-wave modes to quantized ones and vice versa. The lattice constant also influences this variation in spin-wave spectra and spin-wave mode profiles. These observations are important for potential applications of the antidot lattices with triangular holes in future magnonic and spintronic devices.

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

Journal of Applied Physics ◽

10.1063/1.4948354 ◽

2016 ◽

Vol 119 (17) ◽

pp. 173901 ◽

Cited By ~ 7

Author(s):

Matthias Noske ◽

Hermann Stoll ◽

Manfred Fähnle ◽

Ajay Gangwar ◽

Georg Woltersdorf ◽

...

Keyword(s):

Spin Wave ◽

Vortex Core ◽

Essential Role ◽

Three Dimensional ◽

Magnetization Dynamics

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Time-resolved imaging of three-dimensional nanoscale magnetization dynamics

Nature Nanotechnology ◽

10.1038/s41565-020-0649-x ◽

2020 ◽

Vol 15 (5) ◽

pp. 356-360 ◽

Cited By ~ 12

Author(s):

Claire Donnelly ◽

Simone Finizio ◽

Sebastian Gliga ◽

Mirko Holler ◽

Aleš Hrabec ◽

...

Keyword(s):

Three Dimensional ◽

Magnetization Dynamics ◽

Time Resolved ◽

Time Resolved Imaging

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Demonstration of k-vector selective microscopy for nanoscale mapping of higher order spin wave modes

Nanoscale ◽

10.1039/d0nr02132f ◽

2020 ◽

Vol 12 (33) ◽

pp. 17238-17244 ◽

Cited By ~ 2

Author(s):

Nick Träger ◽

Paweł Gruszecki ◽

Filip Lisiecki ◽

Felix Groß ◽

Johannes Förster ◽

...

Keyword(s):

Spin Wave ◽

Real Space ◽

Higher Order ◽

Time Resolved ◽

Excited Mode ◽

Wave Modes

Time resolved STXM provides deep insights into efficient excitation of symmetric and antisysmmetric higher order spin wave modes in magnonic waveguides. k-selective imaging reveals real space information of simultaneously excited mode patterns.

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Spin Wave Modes and Dynamics of Three-Dimensional Magnetic Nanodisks under Perpendicular Resonant Magnetic Field

Advances in Condensed Matter Physics ◽

10.12677/cmp.2019.82006 ◽

2019 ◽

Vol 08 (02) ◽

pp. 41-51

Author(s):

金明许

Keyword(s):

Magnetic Field ◽

Spin Wave ◽

Three Dimensional ◽

Wave Modes

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The angular dependence of magnetization dynamics induced by a GHz range strain pulse

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac4a04 ◽

2022 ◽

Author(s):

Kakeru Tojo ◽

Akira NAGAKUBO ◽

Hirotsugu OGI

Keyword(s):

Magnetic Field ◽

Angular Dependence ◽

Spin Wave ◽

Echo Signal ◽

Magnetization Dynamics ◽

Time Resolved ◽

Wave Resonance ◽

Out Of Plane ◽

Magneto Optical Kerr Effect ◽

Strain Pulse

Abstract The dynamics of magnetization is important in spintronics, where the coupling between phonon and magnon attracts much attention. In this work, we study the angular dependence of the coupling between longitudinal-wave phonon and magnon. We investigated the magnetization dynamics using the time-resolved magneto-optical Kerr effect, which allows measuring spin-wave resonances and the magnetic echo signal. The frequency, mode number, and amplitude of the spin-wave resonance change with the out-of-plane angle of the external magnetic field. The amplitude of the magnetic echo signal caused by the strain pulse also changes with the angle. We calculate these angular dependences based on the Landau-Lifshitz-Gilbert equation and find that the angles of the external field and magnetic moment are important factors for the phonon-magnon coupling when phonon propagates in the thickness direction under the out-of-plane magnetic field.

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The role of ultrafast magnon generation in the magnetization dynamics of rare-earth metals

Science Advances ◽

10.1126/sciadv.abb1601 ◽

2020 ◽

Vol 6 (39) ◽

pp. eabb1601 ◽

Cited By ~ 1

Author(s):

B. Frietsch ◽

A. Donges ◽

R. Carley ◽

M. Teichmann ◽

J. Bowlan ◽

...

Keyword(s):

Rare Earth ◽

Spin Dynamics ◽

Magnetic Moments ◽

Rare Earth Metals ◽

Ultrafast Dynamics ◽

Magnetization Dynamics ◽

Time Resolved ◽

Spin Lattice ◽

Dynamics Simulations

Ultrafast demagnetization of rare-earth metals is distinct from that of 3d ferromagnets, as rare-earth magnetism is dominated by localized 4f electrons that cannot be directly excited by an optical laser pulse. Their demagnetization must involve excitation of magnons, driven either through exchange coupling between the 5d6s-itinerant and 4f-localized electrons or by coupling of 4f spins to lattice excitations. Here, we disentangle the ultrafast dynamics of 5d6s and 4f magnetic moments in terbium metal by time-resolved photoemission spectroscopy. We show that the demagnetization time of the Tb 4f magnetic moments of 400 fs is set by 4f spin–lattice coupling. This is experimentally evidenced by a comparison to ferromagnetic gadolinium and supported by orbital-resolved spin dynamics simulations. Our findings establish coupling of the 4f spins to the lattice via the orbital momentum as an essential mechanism driving magnetization dynamics via ultrafast magnon generation in technically relevant materials with strong magnetic anisotropy.

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Ultrafast magnetization dynamics of spintronic nanostructures

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2010.0324 ◽

2011 ◽

Vol 369 (1948) ◽

pp. 3115-3135 ◽

Cited By ~ 17

Author(s):

P. S. Keatley ◽

V. V. Kruglyak ◽

P. Gangmei ◽

R. J. Hicken

Keyword(s):

Giant Magnetoresistance ◽

Resonant Mode ◽

Physical Structure ◽

Spin Transfer Torque ◽

Magnetization Dynamics ◽

Time Resolved ◽

Spintronic Devices ◽

Mode Spectrum ◽

Ferromagnetic Thin Films ◽

Ultrafast Magnetization

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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