| 1. |
- Chumak, A. V., et al.
(författare)
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Advances in Magnetics Roadmap on Spin-Wave Computing
- 2022
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Ingår i: IEEE Transactions on Magnetics. - 0018-9464. ; 58:6
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Tidskriftsartikel (refereegranskat)abstract
- Magnonics addresses the physical properties of spin waves and utilizes them for data processing. Scalability down to atomic dimensions, operation in the GHz-to-THz frequency range, utilization of nonlinear and nonreciprocal phenomena, and compatibility with CMOS are just a few of many advantages offered by magnons. Although magnonics is still primarily positioned in the academic domain, the scientific and technological challenges of the field are being extensively investigated, and many proof-of-concept prototypes have already been realized in laboratories. This roadmap is a product of the collective work of many authors that covers versatile spin-wave computing approaches, conceptual building blocks, and underlying physical phenomena. In particular, the roadmap discusses the computation operations with Boolean digital data, unconventional approaches like neuromorphic computing, and the progress towards magnon-based quantum computing. The article is organized as a collection of sub-sections grouped into seven large thematic sections. Each sub-section is prepared by one or a group of authors and concludes with a brief description of current challenges and the outlook of further development for each research direction. Author
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| 2. |
- Ovsyannikov, Gennady, 1948, et al.
(författare)
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Magnetotransport characteristics of strained La0.7Sr0.3MnO3 epitaxial manganite films
- 2009
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Ingår i: Journal of Experimental and Theoretical Physics. - 1090-6509 .- 1063-7761. ; 108:1, s. 48-55
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Tidskriftsartikel (refereegranskat)abstract
- The electrical and magnetic characteristics of La0.7Sr0.3MnO3 (LSMO) epitaxial manganite films are investigated by different methods under conditions when the crystal structure is strongly strained as a result of mismatch between the lattice parameters of the LSMO crystal and the substrate. Substrates with lattice parameters larger and smaller than the nominal lattice parameter of the LSMO crystal are used in experiments. It is shown that the behavior of the temperature dependence of the electrical resistance for the films in the low-temperature range does not depend on the strain of the film and agrees well with the results obtained from the calculations with allowance made for the interaction of electrons with magnetic excitations in the framework of the double-exchange model for systems with strongly correlated electronic states. Investigations of the magneto- optical Kerr effect have revealed that an insignificant (0.3%) orthorhombic distortion of the cubic lattice in the plane of the NdGaO3(110) substrate leads to uniaxial anisotropy of the magnetization of the film, with the easy-magnetization axis lying in the substrate plane. However, LSMO films on substrates (((LaAlO3)(0.3)+(Sr2AlTaO6)(0.7))(001)) ensuring minimum strain of the films exhibit a biaxial anisotropy typical of cubic crystals. The study of the ferromagnetic resonance lines at a frequency of 9.76 GHz confirms the results of magnetooptical investigations and indicates that the ferromagnetic phase in the LSMO films is weakly inhomogeneous.
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| 3. |
- Vilkov, E. A., et al.
(författare)
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Dynamics of Spatially Inhomogeneous Spin Polarization of Nonequilibrium Conduction Electrons in Magnetic Transitions
- 2019
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Ingår i: Physics of the solid state. - : PLEIADES PUBLISHING INC. - 1063-7834 .- 1090-6460. ; 61:6, s. 941-951
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Tidskriftsartikel (refereegranskat)abstract
- The equation of the dynamics of the magnetic moment motion that has been averaged over the ensemble of nonequilibrium spin-injected electrons in a ferromagnetic transition in the presence of exchange interaction, interaction with an external electromagnetic field, and a thermostat has been obtained taking into account the spatial inhomogeneity of the charge carrier distribution. It has been shown that taking into account the spatial inhomogeneity of the charge carrier distribution in the equation of the dynamics of the magnetic moment motion allows for describing the various processes of electron transfer in the magnetic transition. The probability of quantum transitions of electrons with opposite spin directions, which determine spin relaxation in interaction with a thermostat, has been estimated. It has been shown that the anisotropy of the radiation medium is determined not only by the anisotropy of the sd-exchange tensor, but also by the additional anisotropy that is caused by the electron impulse derivatives of this tensor. The considered phenomena have a great potential for the detection of new effects and development of new devices based on them, including compact tunable radiation sources in the terahertz frequency range, which is obviously difficult to generate.
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| 4. |
- Vilkov, E. A., et al.
(författare)
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Spin Polarization Dynamics of Nonequilibrium Conduction Electrons in Magnetic Junctions
- 2018
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Ingår i: Journal of Experimental and Theoretical Physics. - : Pleiades Publishing. - 1063-7761 .- 1090-6509. ; 127:6, s. 1022-1032
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of the motion of the magnetic moment averaged over an ensemble of nonequilibrium spin-injected electrons in a ferromagnetic junction is considered with allowance for the exchange interaction, as well as the interaction with an external electromagnetic field and a thermostat. The solution of this problem is important for the experimental development of compact terahertz-band radiation sources. The rate of quantum transitions of electrons with opposite spins, which determine the spin relaxation under the interaction with a thermostat, is calculated within the density matrix formalism. It is shown that two spin-relaxation modes can be implemented that correspond to low- and high-Q precession of spin-nonequilibrium injected electrons. The effect of the characteristic features of spin-flip transitions under the relaxation of the magnetic moment on the emission and absorption of photons with-energy corresponding to the energy of effective exchange splitting of spin subbands is discussed.
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| 5. |
- Vilkov, E. A., et al.
(författare)
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Динамика пространственно неоднородной спиновой поляризации неравновесных электронов проводимости в магнитных переходах
- 2019
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Ingår i: Fizika tverdogo tela. - Moscow. - 0367-3294. ; 61:6, s. 1021-1030
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Tidskriftsartikel (refereegranskat)abstract
- С учетом пространственной неоднородности распределения носителей заряда получено уравнение динамики движения магнитного момента, усредненного по ансамблю неравновесных спин-инжектированных электронов в ферромагнитном переходе, при наличии обменного взаимодействия, взаимодействия с внешним электромагнитным полем и с термостатом. Показано, что учет пространственной неоднородности распределения носителей заряда в уравнении динамики движения магнитного момента позволяет описать различные процессы переноса электронов в магнитном переходе. Оценена вероятность квантовых переходов электронов с противоположными направлениями спина, определяющих спиновую релаксацию при взаимодействии с термостатом. Показано, что анизотропия среды излучения определяется не только анизотропией тензора sd-обмена, но также и дополнительной анизотропией, связанной с производными этого тензора по импульсу электронов. Рассмотренные явления имеют большой потенциал для обнаружения новых эффектов и разработки на их основе новых устройств, в том числе компактных перестраиваемых источников излучения в заведомо трудном для генерации терагерцовом диапазоне частот.
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| 6. |
- Demidov, V. V., et al.
(författare)
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Magnetic Anisotropy of Strained Epitaxial Manganite Films
- 2011
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Ingår i: Journal of Experimental and Theoretical Physics. - : Pleiades Publishing Ltd. - 1090-6509 .- 1063-7761. ; 112:5, s. 825-832
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Tidskriftsartikel (refereegranskat)abstract
- The in-plane magnetic anisotropy of epitaxial La(0.7)Sr(0.3)MnO(3) (LSMO) films is studied at room temperature by the following three independent techniques: magnetooptical Kerr effect, ferromagnetic resonance at a frequency of 9.61 GHz, and recording of absorption spectra of electromagnetic radiation at a frequency of 290.6 MHz. The films are deposited onto NdGaO(3) (NGO) substrates in which the (110) NGO plane is tilted at an angle of 0-25.7 degrees to the substrate plane. The uniaxial magnetic anisotropy induced by the strain of the film is found to increase with the tilt angle of the (110) NGO plane. A model is proposed to describe the change in the magnetic anisotropy energy with the tilt angle. A sharp increase in the radio-frequency absorption in a narrow angular range of a dc magnetic field near a hard magnetization axis is detected The anisotropy parameters of the LSMO films grown on (110) NGO, (001) SrTiO(3), and (001)[(LaAlO(3))(0.3) + (Sr(2)AlTaO(6))(0.7)] substrates are compared.
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| 7. |
- Vilkov, E. A., et al.
(författare)
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Frequency tuning of the spin-injection radiation in the magnetic contact junction
- 2016
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Ingår i: Journal of communications technology & electronics. - : Maik Nauka/Interperiodica. - 1064-2269 .- 1555-6557. ; 61:9, s. 995-1002
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Tidskriftsartikel (refereegranskat)abstract
- The frequency tuning of the terahertz radiation of spin-injection oscillator based on magnetic contact junction that is formed by contacting ferromagnetic metal layers with different magnetizations is analyzed. Under the current-induced spin injection from one magnetic layer (injector) to another (working) layer, the interval of radiation frequencies is determined by the current density in the magnetic contact, the mismatch angle of the magnetizations of injector and working layer, and the equilibrium spin polarization. The wide-range tuning of terahertz frequencies of the spin-injection radiation can be implemented using variations in the above parameters.
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| 8. |
- Litvinenko, A., et al.
(författare)
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Tunable Magnetoacoustic Oscillator with Low Phase Noise
- 2021
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Ingår i: Physical Review Applied. - 2331-7019. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- A frequency-tunable low-phase-noise magnetoacoustic resonator is developed on the base of a parallel plate straight-edge bilayer consisting of an yttrium-iron-garnet (YIG) layer grown on a substrate of a gallium gadolinium garnet (GGG). When a YIG-GGG sample forms an ideal parallel plate, it supports a series of high-quality-factor acoustic modes standing along the plate thickness. Due to the magnetostriction of the YIG layer the ferromagnetic resonance (FMR) mode of the YIG layer can strongly interact with the acoustic thickness modes of the YIG-GGG structure, when the modes' frequencies match. A particular acoustic thickness mode used for the resonance excitations of the hybrid magnetoacoustic oscillations in a YIG-GGG bilayer is chosen by the YIG-layer FMR frequency, which can be tuned by the variation of the external bias magnetic field. A composite scheme of a magnetoacoustic oscillator, which includes a FMR-based resonance preselector, is developed to guarantee satisfaction of the Barkhausen criteria for a single-acoustic-mode oscillation regime. The developed low-phase-noise composite magnetoacoustic oscillator can be tuned from 0.84 to 1 GHz with an increment of about 4.773 MHz (frequency distance between the adjacent acoustic thickness modes in a YIG-GGG parallel plate), and demonstrates the phase noise of & minus;116 dBc/Hz at the offset frequency of 10 kHz.
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