Optical Excitation of Propagating Magnetostatic Waves in an Epitaxial Galfenol Film by Ultrafast Magnetic Anisotropy Change

Khokhlov, N. E.; Gerevenkov, P. I.; Shelukhin, L. A.; Azovtsev, Andrei V.; Pertsev, N. A.; Wang, M.; Rushforth, A. W.; Scherbakov, A. V.; Kalashnikova, A.M.

doi:10.1103/physrevapplied.12.044044

Cited by 32 publications

(46 citation statements)

References 64 publications

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“…We also consider only the ground magnon mode with zero wave vector, that is, we assume a uniform precession, due to the large diameter (17 μm) of the excitation spot, which limits the in-plane wave vector of magnons to q || ≤ 4700 cm −1 . In the 5-nm-thick Galfenol layer, the frequency range for such q || does not exceed 270 MHz 18,19 , which is clearly below the 500 MHz spectral width of the fundamental magnon mode. For details of the magnon dispersion and contribution of magnons with finite wave vectors in a 100-nm-thick layer, see Supplementary Note 4.…”

Section: Discussionmentioning

confidence: 87%

Resonant thermal energy transfer to magnons in a ferromagnetic nanolayer

et al. 2020

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Energy harvesting is a concept which makes dissipated heat useful by transferring thermal energy to other excitations. Most of the existing principles are realized in systems which are heated continuously. We present the concept of high-frequency energy harvesting where the dissipated heat in a sample excites resonant magnons in a thin ferromagnetic metal layer. The sample is excited by femtosecond laser pulses with a repetition rate of 10 GHz, which results in temperature modulation at the same frequency with amplitude~0.1 K. The alternating temperature excites magnons in the ferromagnetic nanolayer which are detected by measuring the net magnetization precession. When the magnon frequency is brought onto resonance with the optical excitation, a 12-fold increase of the amplitude of precession indicates efficient resonant heat transfer from the lattice to coherent magnons. The demonstrated principle may be used for energy harvesting in various nanodevices operating at GHz and sub-THz frequency ranges.

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Section: Discussionmentioning

confidence: 87%

Resonant thermal energy transfer to magnons in a ferromagnetic nanolayer

et al. 2020

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“…Hence, laser excitation may be used to trigger such a transition on a picosecond time scale via changes of B 1 and the film strain. Finally, laser-induced changes of magnetoelastic anisotropy may be employed for driving spin waves [67] in switchable magnonic waveguides based on Co 40 Fe 40 B 20 /BaTiO 3 structures [25,27,68,69].…”

Section: Discussionmentioning

confidence: 99%

Laser-Induced Magnetization Precession in Individual Magnetoelastic Domains of a Multiferroic Co40Fe40B20/BaTiO

et al. 2020

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Using a magneto-optical pump-probe technique with micrometer spatial resolution, we show that magnetization precession can be launched in individual magnetic domains imprinted in a Co 40 Fe 40 B 20 layer by elastic coupling to ferroelectric domains in a BaTiO 3 substrate. The dependence of the precession parameters on the strength and orientation of the external magnetic field reveals that laser-induced ultrafast partial quenching of the magnetoelastic coupling parameter of Co 40 Fe 40 B 20 by approximately 27% along with 10% ultrafast demagnetization triggers the magnetization precession. The relation between the laser-induced reduction of the magnetoelastic coupling and the demagnetization is approximated by an n(n + 1)/2 law with n ≈ 2. This correspondence confirms the thermal origin of the laser-induced anisotropy change. Based on analysis and modeling of the excited precession, we find signatures of laser-induced precessional switching, which occurs when the magnetic field is applied along the hard magnetization axis and its value is close to the effective magnetoelastic anisotropy field. The precessionexcitation process in an individual magnetoelastic domain is found to be unaffected by neighboring domains. This makes laser-induced changes of magnetoelastic anisotropy a promising tool for driving magnetization dynamics and switching in composite multiferroics with spatial selectivity.

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“…Это накладывает ограничения на геометрию экспериментанеобходимость вывода намагниченности из плоскости пленки. Это ограничение было преодолено в работе [125], где в качестве возбуждающего механизма выступало сверхбыстрое изменение магнитокристаллической анизотропии. Для реализации эксперимента авторы использовали 20 nm пленку галфенола (Fe 81 Ga 19 ) с сильной магнитокристаллической кубической анизотропией и наведенной ростовой анизотропией типа легкая ось.…”

Section: сверхбыстрое изменение магнитной анизотропии и возбуждение свunclassified

“…Схемы реализации двумерного детектирования оптически возбуждаемых спиновых волн: a -импульсы накачки и зондовый фокусируются на поверхность образца через один микрообъектив или линзу; относительное смещение пятен на образце достигается за счет изменения угла падения одного из импульсов поворотным зеркалом до объектива[110]; b -импульсы накачки и зондовый фокусируются на поверхность образца с двух сторон через два различных микрообъектива; относительное смещение пятен на образце достигается смещением одного из объективов[125]; c -использование ПЗС-матрицы для получения информации о намагниченности сразу в некоторой площади образца[124]. (Рисунки воспроизведены из[110] (a),[125] (b),[124] (c). )…”

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Сверхбыстрое Лазерно-Индуцированное Управление Магнитной Анизотропией Наноструктур

Калашникова¹,

Хохлов²,

Шелухин³

et al. 2021

Журнал Технической Физики

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Employing short laser pulses with a duration below 100 fs for changing magnetic state of magnetically-ordered media has developed into a distinct branch of magnetism —femtomagnetism which aims at controlling magnetization at ultimately short timescales. Among plethora of femtomagnetic phenomena, there is a class related to impact of femtosecond pulses on magnetic anisotropy of materials and nanostructures which defines orientation of magnetization, magnetic resonance frequencies and spin waves propagation. We present a review of main experimental results obtained in this field. We consider basic mechanisms responsible for a laser-induced change of various anisotropy types: magnetocrystalline, magnetoelastic, interfacial, shape anisotropy, and discuss specifics of these processes in magnetic metals and dielectrics. We consider several examples and describe features of magnetic anisotropy changes resulting from ultrafast laser-induced heating, impact of laser-induced dynamic and quasistatic strains and resonant excitation of electronic states. We also discuss perspectives of employing various mechanisms of laser-induced magnetic anisotropy change for enabling processes prospective for developing devices. We consider precessional magnetization switching for opto-magnetic information recording, generation of high-frequency strongly localized magnetic excitations and fields for magnetic nanotomography and hybrid magnonics, as well as controlling spin waves propagation for optically-reconfigurable magnonics. We further discuss opportunities which open up in studies of ultrafast magnetic anisotropy changes because of using short laser pulses in infrared and terahertz ranges.

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Optical Excitation of Propagating Magnetostatic Waves in an Epitaxial Galfenol Film by Ultrafast Magnetic Anisotropy Change

Cited by 32 publications

References 64 publications

Resonant thermal energy transfer to magnons in a ferromagnetic nanolayer

Resonant thermal energy transfer to magnons in a ferromagnetic nanolayer

Laser-Induced Magnetization Precession in Individual Magnetoelastic Domains of a Multiferroic Co40Fe40B20/BaTiO

Сверхбыстрое Лазерно-Индуцированное Управление Магнитной Анизотропией Наноструктур

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