The Experts below are selected from a list of 114741 Experts worldwide ranked by ideXlab platform
B Hillebrands - One of the best experts on this subject based on the ideXlab platform.
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propagating magnetic droplet solitons as moveable nanoscale Spin Wave sources with tunable direction of emission
Physical review applied, 2020Co-Authors: Morteza Mohseni, Qi Wang, Thomas Bracher, B Hillebrands, Majid Mohseni, Philipp PirroAbstract:Magnetic droplets are strongly nonlinear and localized Spin-Wave solitons that can be formed in current-driven nanocontacts. Here, we propose a simple way to launch droplets in an inhomogeneous nanoscopic Waveguide. We use the drift motion of a droplet and show that in a system with broken translational symmetry, the droplet acquires a linear momentum and propagates. We find that the droplet velocity can be tuned via the strength of the break in symmetry and the size of the nanocontact. In addition, we demonstrate that the launched droplet can propagate up to several micrometers in a realistic system with reasonable damping. Finally, we demonstrate how an annihilating droplet delivers its momentum to a highly nonreciprocal Spin-Wave burst with a tunable Wave vector with nanometer Wavelengths. Such a propagating droplet can be used as a moveable Spin-Wave source in nanoscale magnonic networks. The presented method enables full control of the Spin-Wave emission direction, which can largely extend the freedom to design integrated magnonic circuits with a single Spin-Wave source.
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Spin Wave optical elements towards Spin Wave fourier optics
arXiv: Applied Physics, 2019Co-Authors: Marc Vogel, B Hillebrands, Georg Von FreymannAbstract:We perform micromagnetic simulations to investigate the propagation of Spin-Wave beams through Spin-Wave optical elements. Despite Spin-Wave propagation in magnetic media being strongly anisotropic, we use axicons to excite SpinWave Bessel-Gaussian beams and gradient-index lenses to focus Spin Waves in analogy to conventional optics with light in isotropic media. Moreover, we demonstrate Spin-Wave Fourier optics using gradient-index lenses. These results contribute to the growing field of Spin-Wave optics.
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realization of a Spin Wave switch based on the Spin transfer torque effect
IEEE Magnetics Letters, 2018Co-Authors: Thomas J Meyer, Thomas Bracher, B Hillebrands, A A Serga, Frank Heussner, Hiroshi Naganuma, K Mukaiyama, Mikihiko Oogane, Yasuo Ando, Philipp PirroAbstract:We investigate the amplification of externally excited Spin-Waves via the Spin-transfer-torque (STT) effect in combination with the Spin-Hall effect (SHE) resulting from short current pulses. In the case of overcompensation of the Spin-Wave damping, a strong nonlinear shift of the Spin-Wave frequency spectrum occurs. In particular, this shift limits Spin-Wave amplification from the SHE-STT effect. However, it allows for the realization of a Spin-Wave switch. At the corresponding working point, efficient Spin-Wave excitation is possible only in the presence of the SHE-STT effect with a Spin-Wave intensity that is a factor of 20 larger than in the absence of the SHE-STT effect.
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realization of a Spin Wave switch based on the Spin transfer torque effect
arXiv: Mesoscale and Nanoscale Physics, 2018Co-Authors: Thomas J Meyer, Thomas Bracher, B Hillebrands, A A Serga, Frank Heussner, Hiroshi Naganuma, K Mukaiyama, Mikihiko Oogane, Yasuo Ando, Philipp PirroAbstract:We investigate the amplification of externally excited Spin Waves via the Spin-Transfer-Torque (STT) effect in combination with the Spin-Hall-Effect (SHE) employing short current pulses. The results reveal that, in the case of an overcompensation of the Spin Wave damping, a strong nonlinear shift of the Spin Wave frequency spectrum occurs. In particular, this shift affects the Spin Wave amplification using the SHE-STT effect. In contrast, this effect allows for the realization of a Spin Wave switch. By determining the corresponding working point, an efficient Spin Wave excitation is only possible in the presence of the SHE-STT effect yielding an increased Spin Wave intensity of a factor of 20 compared to the absence of the SHE-STT effect.
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reconfigurable nanoscale Spin Wave directional coupler
Science Advances, 2018Co-Authors: Qi Wang, Philipp Pirro, B Hillebrands, Roman Verba, A N Slavin, A V ChumakAbstract:Spin Waves, and their quanta magnons, are prospective data carriers in future signal processing systems because Gilbert damping associated with the Spin-Wave propagation can be made substantially lower than the Joule heat losses in electronic devices. Although individual Spin-Wave signal processing devices have been successfully developed, the challenging contemporary problem is the formation of two-dimensional planar integrated Spin-Wave circuits. Using both micromagnetic modeling and analytical theory, we present an effective solution of this problem based on the dipolar interaction between two laterally adjacent nanoscale Spin-Wave Waveguides. The developed device based on this principle can work as a multifunctional and dynamically reconfigurable signal directional coupler performing the functions of a Waveguide crossing element, tunable power splitter, frequency separator, or multiplexer. The proposed design of a Spin-Wave directional coupler can be used both in digital logic circuits intended for Spin-Wave computing and in analog microWave signal processing devices.
S O Demokritov - One of the best experts on this subject based on the ideXlab platform.
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Spin Wave propagation in ultra thin yig based Waveguides
Applied Physics Letters, 2017Co-Authors: Martin Collet, O Gladii, M Evelt, V D Bessonov, Lucile Soumah, Paolo Bortolotti, S O Demokritov, Y Henry, Vincent CrosAbstract:Spin-Wave propagation in microfabricated 20 nm thick, 2.5 μm wide Yttrium Iron Garnet (YIG) Waveguides is studied using propagating Spin-Wave spectroscopy (PSWS) and phase resolved micro-focused Brillouin Light Scattering (μ-BLS) spectroscopy. We demonstrate that Spin-Wave propagation in 50 parallel Waveguides is robust against microfabrication induced imperfections and extract Spin-Wave propagation parameters for the Damon-Eshbach configuration in a wide range of excitation frequencies. As expected from its low damping, YIG allows for the propagation of Spin Waves over long distances; the attenuation lengths is 25 μm at μ 0 H = 45 mT. Moreover, direct mapping of Spin Waves by μ-BLS allows us to reconstruct the Spin-Wave dispersion relation and to confirm the multi-mode propagation in the Waveguides, glimpsed by propagating Spin-Wave spectroscopy.
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Spin Wave propagation in ultra thin yig based Waveguides
arXiv: Mesoscale and Nanoscale Physics, 2016Co-Authors: Martin Collet, O Gladii, M Evelt, V D Bessonov, Lucile Soumah, Paolo Bortolotti, S O Demokritov, Y Henry, Vincent CrosAbstract:Spin-Wave propagation in an assembly of microfabricated 20 nm thick, 2.5 {\mu}m wide Yttrium Iron Garnet (YIG) Waveguides is studied using propagating Spin-Wave spectroscopy (PSWS) and phase resolved micro-focused Brillouin Light Scattering ({\mu}-BLS) spectroscopy. We show that Spin-Wave propagation in 50 parallel Waveguides is robust against microfabrication induced imperfections. Spin-Wave propagation parameters are studied in a wide range of excitation frequencies for the Damon-Eshbach (DE) configuration. As expected from its low damping, YIG allows the propagation of Spin Waves over long distances (the attenuation lengths is 25 {\mu}m at \mu$_{0}$H = 45 mT). Direct mapping of Spin Waves by {\mu}-BLS allows us to reconstruct the Spin-Wave dispersion relation and to confirm the multi-mode propagation in the Waveguides, glimpsed by propagating Spin-Wave spectroscopy.
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dual function phase shifter for Spin Wave logic applications
Applied Physics Letters, 2009Co-Authors: Ulfhendrik Hansen, V E Demidov, S O DemokritovAbstract:We have studied experimentally the linear and nonlinear control over the phase accumulation in a Spin-Wave phase shifter, which is a key element for construction of Spin-Wave logic devices. The linear control is realized by creation of a local inhomogeneity of the bias magnetic field, whereas the nonlinear control is based on the shift in the Spin-Wave dispersion spectrum with the increase in the Spin-Wave amplitude. We show that in a single device these two mechanisms can have comparable efficiencies and relatively small cross talk, which allows their simultaneous use for realization of dual-argument logic operations.
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transformation of propagating Spin Wave modes in microscopic Waveguides with variable width
Physical Review B, 2009Co-Authors: V E Demidov, S O Demokritov, J Jersch, Karsten Rott, Patryk Krzysteczko, Gunter ReissAbstract:We have studied experimentally the propagation of Spin Waves in microscopic transversally magnetized permalloy stripe Waveguides with variable width. Spatially resolved measurement based on the microfocus Brillouin light-scattering spectroscopy allowed a direct observation of transformations of propagating transverse Spin-Wave modes in the region of the width transition. Our experiments show that due to the variation in the internal demagnetizing fields caused by the width variation, an effective control of the Spin-Wave propagation can be achieved. In particular, a splitting of a Spin-Wave beam into two independent beams or preferred excitation of certain transverse Spin-Wave modes can be realized.
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Spin Wave eigenmodes of permalloy squares with a closure domain structure
Physical Review Letters, 2005Co-Authors: Korbinian Perzlmaier, B Hillebrands, V E Demidov, Matthias Buess, C H Back, S O DemokritovAbstract:Quantized Spin-Wave eigenmodes in single, 16 nm thick and 0.75 to 4 µm wide square permalloy islands with a fourfold closure domain structure have been investigated by microfocus Brillouin light scattering spectroscopy and time resolved scanning magneto-optical Kerr microscopy. Up to six eigenmodes were detected and classified. The main direction of the Spin-Wave quantization in the domains was found to be perpendicular to the local static magnetization. An additional less pronounced quantization along the direction parallel to the static magnetization was also observed.
Philipp Pirro - One of the best experts on this subject based on the ideXlab platform.
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propagating magnetic droplet solitons as moveable nanoscale Spin Wave sources with tunable direction of emission
Physical review applied, 2020Co-Authors: Morteza Mohseni, Qi Wang, Thomas Bracher, B Hillebrands, Majid Mohseni, Philipp PirroAbstract:Magnetic droplets are strongly nonlinear and localized Spin-Wave solitons that can be formed in current-driven nanocontacts. Here, we propose a simple way to launch droplets in an inhomogeneous nanoscopic Waveguide. We use the drift motion of a droplet and show that in a system with broken translational symmetry, the droplet acquires a linear momentum and propagates. We find that the droplet velocity can be tuned via the strength of the break in symmetry and the size of the nanocontact. In addition, we demonstrate that the launched droplet can propagate up to several micrometers in a realistic system with reasonable damping. Finally, we demonstrate how an annihilating droplet delivers its momentum to a highly nonreciprocal Spin-Wave burst with a tunable Wave vector with nanometer Wavelengths. Such a propagating droplet can be used as a moveable Spin-Wave source in nanoscale magnonic networks. The presented method enables full control of the Spin-Wave emission direction, which can largely extend the freedom to design integrated magnonic circuits with a single Spin-Wave source.
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Spin pinning and Spin Wave dispersion in nanoscopic ferromagnetic Waveguides
Physical Review Letters, 2019Co-Authors: Qi Wang, Philipp Pirro, Roman Verba, Thomas J Meyer, Bjorn Heinz, M Kewenig, Michael Schneider, Bert Lagel, Carsten Dubs, Thomas BracherAbstract:Spin Waves are investigated in yttrium iron garnet Waveguides with a thickness of 39 nm and widths ranging down to 50 nm, i.e., with an aspect ratio thickness over width approaching unity, using Brillouin light scattering spectroscopy. The experimental results are verified by a semianalytical theory and micromagnetic simulations. A critical width is found, below which the exchange interaction suppresses the dipolar pinning phenomenon. This changes the quantization criterion for the Spin-Wave eigenmodes and results in a pronounced modification of the Spin-Wave characteristics. The presented semianalytical theory allows for the calculation of Spin-Wave mode profiles and dispersion relations in nanostructures.
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realization of a Spin Wave switch based on the Spin transfer torque effect
IEEE Magnetics Letters, 2018Co-Authors: Thomas J Meyer, Thomas Bracher, B Hillebrands, A A Serga, Frank Heussner, Hiroshi Naganuma, K Mukaiyama, Mikihiko Oogane, Yasuo Ando, Philipp PirroAbstract:We investigate the amplification of externally excited Spin-Waves via the Spin-transfer-torque (STT) effect in combination with the Spin-Hall effect (SHE) resulting from short current pulses. In the case of overcompensation of the Spin-Wave damping, a strong nonlinear shift of the Spin-Wave frequency spectrum occurs. In particular, this shift limits Spin-Wave amplification from the SHE-STT effect. However, it allows for the realization of a Spin-Wave switch. At the corresponding working point, efficient Spin-Wave excitation is possible only in the presence of the SHE-STT effect with a Spin-Wave intensity that is a factor of 20 larger than in the absence of the SHE-STT effect.
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realization of a Spin Wave switch based on the Spin transfer torque effect
arXiv: Mesoscale and Nanoscale Physics, 2018Co-Authors: Thomas J Meyer, Thomas Bracher, B Hillebrands, A A Serga, Frank Heussner, Hiroshi Naganuma, K Mukaiyama, Mikihiko Oogane, Yasuo Ando, Philipp PirroAbstract:We investigate the amplification of externally excited Spin Waves via the Spin-Transfer-Torque (STT) effect in combination with the Spin-Hall-Effect (SHE) employing short current pulses. The results reveal that, in the case of an overcompensation of the Spin Wave damping, a strong nonlinear shift of the Spin Wave frequency spectrum occurs. In particular, this shift affects the Spin Wave amplification using the SHE-STT effect. In contrast, this effect allows for the realization of a Spin Wave switch. By determining the corresponding working point, an efficient Spin Wave excitation is only possible in the presence of the SHE-STT effect yielding an increased Spin Wave intensity of a factor of 20 compared to the absence of the SHE-STT effect.
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reconfigurable nanoscale Spin Wave directional coupler
Science Advances, 2018Co-Authors: Qi Wang, Philipp Pirro, B Hillebrands, Roman Verba, A N Slavin, A V ChumakAbstract:Spin Waves, and their quanta magnons, are prospective data carriers in future signal processing systems because Gilbert damping associated with the Spin-Wave propagation can be made substantially lower than the Joule heat losses in electronic devices. Although individual Spin-Wave signal processing devices have been successfully developed, the challenging contemporary problem is the formation of two-dimensional planar integrated Spin-Wave circuits. Using both micromagnetic modeling and analytical theory, we present an effective solution of this problem based on the dipolar interaction between two laterally adjacent nanoscale Spin-Wave Waveguides. The developed device based on this principle can work as a multifunctional and dynamically reconfigurable signal directional coupler performing the functions of a Waveguide crossing element, tunable power splitter, frequency separator, or multiplexer. The proposed design of a Spin-Wave directional coupler can be used both in digital logic circuits intended for Spin-Wave computing and in analog microWave signal processing devices.
Hugues De Riedmatten - One of the best experts on this subject based on the ideXlab platform.
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solid state Spin Wave quantum memory for time bin qubits
Physical Review Letters, 2015Co-Authors: Mustafa Gundogan, Patrick M Ledingham, Kutlu Kutluer, Margherita Mazzera, Hugues De RiedmattenAbstract:We demonstrate the first solid-state Spin-Wave optical quantum memory with on-demand read-out. Using the full atomic frequency comb scheme in a Pr(3+):Y2SiO5 crystal, we store weak coherent pulses at the single-photon level with a signal-to-noise ratio >10. Narrow-band spectral filtering based on spectral hole burning in a second Pr(3+):Y2SiO5 crystal is used to filter out the excess noise created by control pulses to reach an unconditional noise level of (2.0±0.3)×10(-3) photons per pulse. We also report Spin-Wave storage of photonic time-bin qubits with conditional fidelities higher than achievable by a measure and prepare strategy, demonstrating that the Spin-Wave memory operates in the quantum regime. This makes our device the first demonstration of a quantum memory for time-bin qubits, with on-demand read-out of the stored quantum information. These results represent an important step for the use of solid-state quantum memories in scalable quantum networks.
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solid state Spin Wave quantum memory for time bin qubits
Physical Review Letters, 2015Co-Authors: Mustafa Gundogan, Patrick M Ledingham, Kutlu Kutluer, Margherita Mazzera, Hugues De RiedmattenAbstract:We demonstrate the first solid-state Spin-Wave optical quantum memory with on-demand read-out. Using the full atomic frequency comb scheme in a ${\mathrm{Pr}}^{3+}\ensuremath{\mathbin:}{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal, we store weak coherent pulses at the single-photon level with a signal-to-noise ratio $g10$. Narrow-band spectral filtering based on spectral hole burning in a second ${\mathrm{Pr}}^{3+}\ensuremath{\mathbin:}{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal is used to filter out the excess noise created by control pulses to reach an unconditional noise level of $(2.0\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ photons per pulse. We also report Spin-Wave storage of photonic time-bin qubits with conditional fidelities higher than achievable by a measure and prepare strategy, demonstrating that the Spin-Wave memory operates in the quantum regime. This makes our device the first demonstration of a quantum memory for time-bin qubits, with on-demand read-out of the stored quantum information. These results represent an important step for the use of solid-state quantum memories in scalable quantum networks.
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demonstration of atomic frequency comb memory for light with Spin Wave storage
Physical Review Letters, 2010Co-Authors: Mikael Afzelius, Imam Usmani, Hugues De Riedmatten, Atia Amari, Bjoern Lauritzen, Andreas Walther, Christoph Simon, Nicolas Sangouard, Jiri Minar, Nicolas GisinAbstract:We present a light-storage experiment in a praseodymium-doped crystal where the light is mapped onto an inhomogeneously broadened optical transition shaped into an atomic frequency comb. After absorption of the light, the optical excitation is converted into a Spin-Wave excitation by a control pulse. A second control pulse reads the memory (on-demand) by reconverting the Spin-Wave excitation to an optical one, where the comb structure causes a photon-echo-type rephasing of the dipole moments and directional retrieval of the light. This combination of photon-echo and Spin-Wave storage allows us to store submicrosecond (450 ns) pulses for up to 20 mu s. The scheme has a high potential for storing multiple temporal modes in the single-photon regime, which is an important resource for future long-distance quantum communication based on quantum repeaters.
B Lake - One of the best experts on this subject based on the ideXlab platform.
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linear Spin Wave theory for single q incommensurate magnetic structures
Journal of Physics: Condensed Matter, 2015Co-Authors: B Lake, S. TóthAbstract:Linear Spin Wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of 1/root S. This term is acquired using the Holstein-Primakoff approximation of the Spin operator and valid for small dS fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering Wave vector using a local coordinate transformation for every Spin and a rotating coordinate transformation for the incommensurability. Finally we show, how our model can determine the Spin Wave spectrum of the magnetic C-site langasites with incommensurate order.
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linear Spin Wave theory for single q incommensurate magnetic structures
arXiv: Strongly Correlated Electrons, 2014Co-Authors: B Lake, S. TóthAbstract:Linear Spin Wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of $1/\sqrt{S}$. This term is acquired using the Holstein-Primakoff approximation of the Spin operator and valid for small $\delta S$ fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering Wave vector using a local coordinate transformation for every Spin and a rotating coordinate transformation for the incommensurability. Finally we show, how our model can determine the Spin Wave spectrum of the magnetic C-site langasites with incommensurate order.
