Novel environment for spin wave propagation: from periodic magnetization textures towards space-time magnonic crystals
Grant
Project No. 2019/35/D/ST3/03729 (National Science Center, Sonata-15), PI: Paweł Gruszecki
Polish title: Nowe środowisko dla propagacji fal spinowych: od periodycznych tekstur magnetycznych do magnonicznych kryształów czasoprzestrzennych
Project description
Magnetic moments can rotate in precessional motion around the direction of the static magnetic field if they are pushed out from the equilibrium position (e.g. by application of the radiofrequency field, or by thermal excitation). In a magnetic medium, due to the interaction between magnetic moments, the waves of coherently precessing magnetic moments can propagate. These waves, (called spin waves), can transmit energy and information, similarly like waves of a different nature (e.g. electromagnetic waves or elastic waves). The systems, which use the spin waves for processing and transmitting information can fill the gap between electronics and photonics. Typical frequencies of spin waves (in the range from a fraction of GHz to hundreds of GHz) and their wavelengths (in the range from tens to hundreds of nanometers) make possible the design of miniaturized devices (called magnonic devices) operating on high-frequency signals. The main advantages of magnonics over the other technologies are (i) simplicity of inducing nonlinear effects (useful in many tasks related to signal processing), (ii) anisotropy in the propagation of waves and (iii) nonreciprocal effects for the propagation of waves making a possible design of circulators and isolators. The dispersion relation describes the dynamical properties of the system operating on coherent signals (i.e. the signals in the form of waves). It gives the fundamental relation between frequency and the wavelength. Dispersion relation allows deriving a lot of features and parameters useful for the description of wave dynamics. We can itemize the following: location and width of the frequency gaps (determining the frequency of the wave where propagation is not allowed through the system), group velocity and phase velocity.
One of the basic methods suitable for spin wave dispersion relation modification is introduction of a periodical modulation of magnetic properties. Created in such a way periodic structure is typically referred to as magnonic crystal and is characterized by the existence of frequency bandgaps with ranges of forbidden frequencies. A unique property of spin waves is the fact that they propagate in magnetic media. Features of this environment, suitable for SWs propagation, can be easily molded, e.g., by the external factors like the magnetic field, but also by the internal magnetization texture. It means, that this periodical modulation can be also introduced by the magnetization texture without any change of system’s structure.
The concept of periodic modulation was just recently extended from space into time, leading to the idea of a time crystal by Wilczek in 2012. The combination of space and time symmetry breakings defines a so-called Space-Time Crystal that exhibits periodicity in space and time. In the frame of this Project we unite the fundamental space-time crystals with the world of magnonics introducing space-time magnonic crystals and present an exceptional case of nonlinear wave physics in a comparatively large structure. Thus, the general objective of this project is the analysis of spin wave dynamics (i) in magnetization textures that are periodical in space, and (ii) ultimately, in a new class of magnetization textures that are periodical both in space and time. The main research hypothesis is based on the assumption regarding a unique potential of nonuniform magnetization textures, especially those exhibiting space-time periodicity, as a medium for SW propagation.
This project will address theoretically few important issues in magnonics and physics. Although the project mainly bases on the theoretical and numerical investigation, the research will also be conducted in collaboration with experimental groups. We want to propose the structures ready for experimental validation or explain the results of measurements that have been already made. Especially, we will focus on magnetic systems based on mono- and multilayers with perpendicular magnetic anisotropy ferromagnetic/”heavy metal” (e.g., Co/Pt and Co/Pd), and also, in some cases, antisymmetric exchange interaction, so-called Dzyaloshinskii–Moriya interaction. Firstly, we will study the application of the transition regions between magnetization domains as ultra-narrow channels with unique properties for SWs propagation and a source of spin waves. Secondly, we will analyze how the properties of media influence the static and dynamic properties of periodic magnetization textures. Finally, we will use the acquired knowledge to analyze the condensation of periodical (in both space and time) magnetization textures, and then their features for SW propagation. This is a new kind of magnetization texture, up-to-date not considered in magnonics. In general, we will verify whether the STMCs form band structures at room temperature and that quasi-particles interact with these lattices like in regular crystals.
We believe that our research promises outstanding new opportunities not only in magnonics but also in fundamental research in non-linear wave physics. These investigations open the possibility for application of the magnonic devices to processing and routing of the high-frequency signals.
Tasks
I. Study of linear and nonlinear spin wave dynamics in
a single domain wall
II. Study of spin wave dynamics in periodic
magnetization textures
III. Study of space-time magnonic crystals condensation
IV. Study of spin wave dynamics in space-time
magnonic crystals
Team
- Principale Investigator (PI) Dr Paweł Gruszecki >>>
- Prof. dr hab. Maciej Krawczyk >>>
- M.Sc. Krzysztof Sobucki >>>
- B.Sc. Nikodem Leśniewski >>>
Publications
2024
Kumar, N; Gruszecki, Paweł; Gołębiewski, Mateusz; Kłos, Jarosław W; Krawczyk, Maciej
Exciting High-Frequency Short-Wavelength Spin Waves using High Harmonics of a Magnonic Cavity Mode-Revision Journal Article
In: Advanced Quantum Technologies, pp. 2400015, 2024.
@article{https://doi.org/10.1002/qute.202400015,
title = {Exciting High-Frequency Short-Wavelength Spin Waves using High Harmonics of a Magnonic Cavity Mode-Revision},
author = {N Kumar and Paweł Gruszecki and Mateusz Gołębiewski and Jarosław W Kłos and Maciej Krawczyk},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/qute.202400015},
doi = {https://doi.org/10.1002/qute.202400015},
year = {2024},
date = {2024-03-29},
urldate = {2024-03-29},
journal = {Advanced Quantum Technologies},
pages = {2400015},
abstract = {Abstract Spin waves (SWs) are promising objects for signal processing and future quantum technologies due to their high microwave frequencies with corresponding nanoscale wavelengths. However, the nano-wavelength SWs generated so far are limited to low frequencies. In the paper, using micromagnetic simulations, it is shown that a microwave-pumped SW mode confined to the cavity of a thin film magnonic crystal (MC) can be used to generate waves at tens of GHz and wavelengths well below 50 nm. These multi-frequency harmonics of the fundamental cavity mode are generated when the amplitude of the pumping microwave field exceeds a threshold, and their intensities then scale linearly with the field intensity. The frequency of the cavity mode is equal to the ferromagnetic resonance frequency of the planar ferromagnetic film, which overlaps with the magnonic bandgap, providing an efficient mechanism for confinement and magnetic field tunability. The effect reaches saturation when the microstrip feed line covers the entire cavity, making the system feasible for realization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Spin waves (SWs) are promising objects for signal processing and future quantum technologies due to their high microwave frequencies with corresponding nanoscale wavelengths. However, the nano-wavelength SWs generated so far are limited to low frequencies. In the paper, using micromagnetic simulations, it is shown that a microwave-pumped SW mode confined to the cavity of a thin film magnonic crystal (MC) can be used to generate waves at tens of GHz and wavelengths well below 50 nm. These multi-frequency harmonics of the fundamental cavity mode are generated when the amplitude of the pumping microwave field exceeds a threshold, and their intensities then scale linearly with the field intensity. The frequency of the cavity mode is equal to the ferromagnetic resonance frequency of the planar ferromagnetic film, which overlaps with the magnonic bandgap, providing an efficient mechanism for confinement and magnetic field tunability. The effect reaches saturation when the microstrip feed line covers the entire cavity, making the system feasible for realization.
2023
Sobucki, Krzysztof; Śmigaj, Wojciech; Graczyk, Piotr; Krawczyk, Maciej; Gruszecki, Paweł
Magnon-Optic Effects with Spin-Wave Leaky Modes: Tunable Goos-Hänchen Shift and Wood’s Anomaly Journal Article
In: Nano Letters, vol. 23, iss. 15, no. 6979–6984, 2023.
@article{sobucki2023b,
title = {Magnon-Optic Effects with Spin-Wave Leaky Modes: Tunable Goos-Hänchen Shift and Wood’s Anomaly},
author = {Krzysztof Sobucki and Wojciech Śmigaj and Piotr Graczyk and Maciej Krawczyk and Paweł Gruszecki},
url = {https://doi.org/10.1021/acs.nanolett.3c01592},
doi = {10.1021/acs.nanolett.3c01592},
year = {2023},
date = {2023-07-31},
urldate = {2023-07-31},
journal = {Nano Letters},
volume = {23},
number = {6979–6984},
issue = {15},
abstract = {We demonstrate numerically how a spin wave (SW) beam obliquely incident on the edge of a thin film placed below a ferromagnetic stripe can excite leaky SWs guided along the stripe. During propagation, leaky waves emit energy back into the layer in the form of plane waves and several laterally shifted parallel SW beams. This resonance excitation, combined with interference effects of the reflected and re-emitted waves, results in the magnonic Wood’s anomaly and a significant increase of the Goos-Hänchen shift magnitude. This yields a unique platform to control SW reflection and transdimensional magnonic router that can transfer SWs from a 2D platform into a 1D guided mode.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We demonstrate numerically how a spin wave (SW) beam obliquely incident on the edge of a thin film placed below a ferromagnetic stripe can excite leaky SWs guided along the stripe. During propagation, leaky waves emit energy back into the layer in the form of plane waves and several laterally shifted parallel SW beams. This resonance excitation, combined with interference effects of the reflected and re-emitted waves, results in the magnonic Wood’s anomaly and a significant increase of the Goos-Hänchen shift magnitude. This yields a unique platform to control SW reflection and transdimensional magnonic router that can transfer SWs from a 2D platform into a 1D guided mode.
Śmigaj, Wojciech; Sobucki, Krzysztof; Gruszecki, Paweł; Krawczyk, Maciej
Modal approach to modeling spin wave scattering Journal Article
In: Phys. Rev. B, vol. 108, iss. 1, no. 15, pp. 014418, 2023.
@article{PhysRevB.108.014418,
title = {Modal approach to modeling spin wave scattering},
author = {Wojciech Śmigaj and Krzysztof Sobucki and Paweł Gruszecki and Maciej Krawczyk},
url = {https://link.aps.org/doi/10.1103/PhysRevB.108.014418},
doi = {10.1103/PhysRevB.108.014418},
year = {2023},
date = {2023-07-14},
journal = {Phys. Rev. B},
volume = {108},
number = {15},
issue = {1},
pages = {014418},
abstract = {Efficient numerical methods are required for the design of optimized devices. In magnonics, the primary computational tool is micromagnetic simulations, which solve the Landau-Lifshitz equation discretized in time and space. However, their computational cost is high, and the complexity of their output hinders insight into the physics of the simulated system, especially in the case of multimode propagating-wave-based devices. We propose a finite-element modal method allowing an efficient solution of the scattering problem for dipole-exchange spin waves propagating perpendicularly to the magnetization direction. The method gives direct access to the scattering matrix of the whole system and its components. We extend the formula for the power carried by a magnetostatic mode in the Damon-Eshbach configuration to the case with exchange, allowing the scattering coefficients to be normalized to represent the fraction of the input power transferred to each output channel. We apply the method to the analysis of spin wave scattering on a basic functional block of magnonic circuits, consisting of a resonator dynamically coupled to a thin film. The results and the method are validated by comparison with micromagnetic simulations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Efficient numerical methods are required for the design of optimized devices. In magnonics, the primary computational tool is micromagnetic simulations, which solve the Landau-Lifshitz equation discretized in time and space. However, their computational cost is high, and the complexity of their output hinders insight into the physics of the simulated system, especially in the case of multimode propagating-wave-based devices. We propose a finite-element modal method allowing an efficient solution of the scattering problem for dipole-exchange spin waves propagating perpendicularly to the magnetization direction. The method gives direct access to the scattering matrix of the whole system and its components. We extend the formula for the power carried by a magnetostatic mode in the Damon-Eshbach configuration to the case with exchange, allowing the scattering coefficients to be normalized to represent the fraction of the input power transferred to each output channel. We apply the method to the analysis of spin wave scattering on a basic functional block of magnonic circuits, consisting of a resonator dynamically coupled to a thin film. The results and the method are validated by comparison with micromagnetic simulations.
Kisielewski, J; Gruszecki, Paweł; Krawczyk, Maciej; Zablotskii, V; Maziewski, A
Between waves and patterns: Spin wave freezing in films with Dzyaloshinskii-Moriya interaction Journal Article
In: Physical Review B, vol. 107, iss. 13, no. 14, pp. 134416, 2023.
@article{PhysRevB.107.134416,
title = {Between waves and patterns: Spin wave freezing in films with Dzyaloshinskii-Moriya interaction},
author = {J Kisielewski and Paweł Gruszecki and Maciej Krawczyk and V Zablotskii and A Maziewski},
doi = {10.1103/PhysRevB.107.134416},
year = {2023},
date = {2023-04-12},
urldate = {2023-04-12},
journal = {Physical Review B},
volume = {107},
number = {14},
issue = {13},
pages = {134416},
abstract = {The relationship between waves and static pattern formation is an intriguing effect and remains unexplained
in many areas of physics, including magnetism. We study the spin-wave-mediated spin reorientation transition
(SRT) in magnetic films with uniaxial magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI). In
particular, we show that propagating spin waves can freeze in the SRT, causing periodic magnetic domains to
arise, which is reminiscent of the wave amplitude distribution. This process can take place under the influence of
a change in the magnetic field, but also of other parameters. Interestingly, at the SRT, DMI nonreciprocity leads
to the emergence of flowing magnetization patterns, which suggests a spontaneous breaking of translational
symmetry, and the formation of magnonic space-time crystals. The described phenomena are general and should
take place in a large family of magnetic materials. Therefore, the results should be of great importance for the
further development of spintronics and magnonics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The relationship between waves and static pattern formation is an intriguing effect and remains unexplained
in many areas of physics, including magnetism. We study the spin-wave-mediated spin reorientation transition
(SRT) in magnetic films with uniaxial magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI). In
particular, we show that propagating spin waves can freeze in the SRT, causing periodic magnetic domains to
arise, which is reminiscent of the wave amplitude distribution. This process can take place under the influence of
a change in the magnetic field, but also of other parameters. Interestingly, at the SRT, DMI nonreciprocity leads
to the emergence of flowing magnetization patterns, which suggests a spontaneous breaking of translational
symmetry, and the formation of magnonic space-time crystals. The described phenomena are general and should
take place in a large family of magnetic materials. Therefore, the results should be of great importance for the
further development of spintronics and magnonics.
in many areas of physics, including magnetism. We study the spin-wave-mediated spin reorientation transition
(SRT) in magnetic films with uniaxial magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI). In
particular, we show that propagating spin waves can freeze in the SRT, causing periodic magnetic domains to
arise, which is reminiscent of the wave amplitude distribution. This process can take place under the influence of
a change in the magnetic field, but also of other parameters. Interestingly, at the SRT, DMI nonreciprocity leads
to the emergence of flowing magnetization patterns, which suggests a spontaneous breaking of translational
symmetry, and the formation of magnonic space-time crystals. The described phenomena are general and should
take place in a large family of magnetic materials. Therefore, the results should be of great importance for the
further development of spintronics and magnonics.
Gruszecki, Paweł; Kisielewski, J
Influence of Dzyaloshinskii–Moriya interaction and perpendicular anisotropy on spin waves propagation in stripe domain patterns and spin spirals Journal Article
In: Scientific Reports, vol. 13, no. 1218, 2023.
@article{gruszecki_influence_23,
title = {Influence of Dzyaloshinskii–Moriya interaction and perpendicular anisotropy on spin waves propagation in stripe domain patterns and spin spirals},
author = {Paweł Gruszecki and J Kisielewski
},
doi = {https://doi.org/10.1038/s41598-023-28271-2},
year = {2023},
date = {2023-01-21},
journal = {Scientific Reports},
volume = {13},
number = {1218},
abstract = {Texture-based magnonics focuses on the utilization of spin waves in magnetization textures to process information. Using micromagnetic simulations, we study how (1) the dynamic magnetic susceptibility, (2) dispersion relations, and (3) the equilibrium magnetic configurations in periodic magnetization textures in a ultrathin ferromagnetic film in remanence depend on the values of the Dzyaloshinskii–Moriya interaction and the perpendicular magnetocrystalline anisotropy. We observe that for large Dzyaloshinskii–Moriya interaction values, spin spirals with periods of tens of nanometers are the preferred state; for small Dzyaloshinskii–Moriya interaction values and large anisotropies, stripe domain patterns with over a thousand times larger period are preferable. We observe and explain the selectivity of the excitation of resonant modes by a linearly polarized microwave field. We study the propagation of spin waves along and perpendicular to the direction of the periodicity. For propagation along the direction of the periodicity, we observe a bandgap that closes and reopens, which is accompanied by a swap in the order of the bands. For waves propagating in the perpendicular direction, some modes can be used for unidirectional channeling of spin waves. Overall, our findings are promising in sensing and signal processing applications and explain the fundamental properties of periodic magnetization textures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Texture-based magnonics focuses on the utilization of spin waves in magnetization textures to process information. Using micromagnetic simulations, we study how (1) the dynamic magnetic susceptibility, (2) dispersion relations, and (3) the equilibrium magnetic configurations in periodic magnetization textures in a ultrathin ferromagnetic film in remanence depend on the values of the Dzyaloshinskii–Moriya interaction and the perpendicular magnetocrystalline anisotropy. We observe that for large Dzyaloshinskii–Moriya interaction values, spin spirals with periods of tens of nanometers are the preferred state; for small Dzyaloshinskii–Moriya interaction values and large anisotropies, stripe domain patterns with over a thousand times larger period are preferable. We observe and explain the selectivity of the excitation of resonant modes by a linearly polarized microwave field. We study the propagation of spin waves along and perpendicular to the direction of the periodicity. For propagation along the direction of the periodicity, we observe a bandgap that closes and reopens, which is accompanied by a swap in the order of the bands. For waves propagating in the perpendicular direction, some modes can be used for unidirectional channeling of spin waves. Overall, our findings are promising in sensing and signal processing applications and explain the fundamental properties of periodic magnetization textures.
2022
Zelent, Mateusz; Gruszecki, Paweł; Moalic, Mathieu; Hellwig, O; Barman, A; Krawczyk, Maciej
Chapter One - Spin dynamics in patterned magnetic multilayers with perpendicular magnetic anisotropy Book Chapter
In: vol. 73, pp. 1-51, Academic Press, 2022, ISBN: 0081-1947.
@inbook{zelent_spin_dym_PMA,
title = {Chapter One - Spin dynamics in patterned magnetic multilayers with perpendicular magnetic anisotropy},
author = {Mateusz Zelent and Paweł Gruszecki and Mathieu Moalic and O Hellwig and A Barman and Maciej Krawczyk},
doi = {https://doi.org/10.1016/bs.ssp.2022.08.002},
isbn = {0081-1947},
year = {2022},
date = {2022-10-27},
urldate = {2022-10-27},
volume = {73},
pages = {1-51},
publisher = {Academic Press},
series = {Solid State Physics},
abstract = {The magnetization dynamics in nanostructures has been extensively studied in the last decades, and nanomagnetism has evolved significantly over that time, discovering new effects, developing numerous applications, and identifying promising new directions. This includes magnonics, an emerging research field oriented on the study of spin-wave dynamics and their applications. In this context, thin ferromagnetic films with perpendicular magnetic anisotropy (PMA) offer interesting opportunities to study spin waves, in particular, due to out-of-plane magnetization in remanence or at relatively weak external magnetic fields. This is the only magnetization configuration offering isotropic in-plane spin-wave propagation within the sample plane, the forward volume magnetostatic spin-wave geometry. The isotropic dispersion relation is highly important in designing signal-processing devices, offering superior prospects for direct replicating various concepts from photonics into magnonics. Analogous to photonic or phononic crystals, which are the building blocks of optoelectronics and phononics, magnonic crystals are considered as key components in magnonics applications. Arrays of nanodots and structured ferromagnetic thin films with a periodic array of holes, popularly known as antidot lattices based on PMA multilayers, have been recently studied. Novel magnonic properties related to propagating spin-wave modes, exploitation of the band gaps, and confined modes were demonstrated. Also, the existence of nontrivial magnonic band topologies has been shown. Moreover, the combination of PMA and Dzyaloshinskii–Moriya interaction leads to the formation of chiral magnetization states, including Néel domain walls, skyrmions, and skyrmionium states. This promotes the multilayers with PMA as an interesting topic for magnonics and this chapter reviews the background and attempts to provide future perspectives in this research field.},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
The magnetization dynamics in nanostructures has been extensively studied in the last decades, and nanomagnetism has evolved significantly over that time, discovering new effects, developing numerous applications, and identifying promising new directions. This includes magnonics, an emerging research field oriented on the study of spin-wave dynamics and their applications. In this context, thin ferromagnetic films with perpendicular magnetic anisotropy (PMA) offer interesting opportunities to study spin waves, in particular, due to out-of-plane magnetization in remanence or at relatively weak external magnetic fields. This is the only magnetization configuration offering isotropic in-plane spin-wave propagation within the sample plane, the forward volume magnetostatic spin-wave geometry. The isotropic dispersion relation is highly important in designing signal-processing devices, offering superior prospects for direct replicating various concepts from photonics into magnonics. Analogous to photonic or phononic crystals, which are the building blocks of optoelectronics and phononics, magnonic crystals are considered as key components in magnonics applications. Arrays of nanodots and structured ferromagnetic thin films with a periodic array of holes, popularly known as antidot lattices based on PMA multilayers, have been recently studied. Novel magnonic properties related to propagating spin-wave modes, exploitation of the band gaps, and confined modes were demonstrated. Also, the existence of nontrivial magnonic band topologies has been shown. Moreover, the combination of PMA and Dzyaloshinskii–Moriya interaction leads to the formation of chiral magnetization states, including Néel domain walls, skyrmions, and skyrmionium states. This promotes the multilayers with PMA as an interesting topic for magnonics and this chapter reviews the background and attempts to provide future perspectives in this research field.
Sobucki, Krzysztof; Krawczyk, Maciej; Tartakovskaya, Elena; Graczyk, Piotr
Magnon spectrum of Bloch hopfion beyond ferromagnetic resonance Journal Article
In: APL Materials, vol. 10, no. 9, pp. 091103, 2022.
@article{magnon_spectrum,
title = {Magnon spectrum of Bloch hopfion beyond ferromagnetic resonance},
author = {Krzysztof Sobucki and Maciej Krawczyk and Elena Tartakovskaya and Piotr Graczyk},
url = { https://doi.org/10.1063/5.0100484},
year = {2022},
date = {2022-09-08},
journal = {APL Materials},
volume = {10},
number = {9},
pages = {091103},
abstract = {With the development of new nanofabrication technologies and measurement techniques, the interest of researchers is moving toward 3D structures and 3D magnetization textures. Special attention is paid to the topological magnetization textures, particularly hopfions. In this paper, we investigate the magnetization dynamics of the hopfion through the numerical solution of the eigenvalue problem. We show that the spectrum of spin-wave modes of the hopfion is much richer than those attainable in ferromagnetic resonance experiments or time-domain simulations reported so far. We identified four groups of modes that differ in the character of oscillations (clockwise or counter-clockwise rotation sense), the position of an average amplitude localization along the radial direction, and different oscillations in the vertical cross section. The knowledge of the full spin-wave spectrum shall help in hopfion identification, understanding of the interaction between spin waves and hopfion dynamics as well as the development of the potential of hopfion in spintronic and magnonic applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
With the development of new nanofabrication technologies and measurement techniques, the interest of researchers is moving toward 3D structures and 3D magnetization textures. Special attention is paid to the topological magnetization textures, particularly hopfions. In this paper, we investigate the magnetization dynamics of the hopfion through the numerical solution of the eigenvalue problem. We show that the spectrum of spin-wave modes of the hopfion is much richer than those attainable in ferromagnetic resonance experiments or time-domain simulations reported so far. We identified four groups of modes that differ in the character of oscillations (clockwise or counter-clockwise rotation sense), the position of an average amplitude localization along the radial direction, and different oscillations in the vertical cross section. The knowledge of the full spin-wave spectrum shall help in hopfion identification, understanding of the interaction between spin waves and hopfion dynamics as well as the development of the potential of hopfion in spintronic and magnonic applications.
Kotus, Katarzyna; Moalic, Mathieu; Zelent, Mateusz; Krawczyk, Maciej; Gruszecki, Paweł
Scattering of spin waves in a multimode waveguide under the influence of confined magnetic skyrmion Journal Article
In: APL Materials, vol. 10, no. 9, pp. 091101, 2022.
@article{doi:10.1063/5.0100594,
title = {Scattering of spin waves in a multimode waveguide under the influence of confined magnetic skyrmion},
author = {Katarzyna Kotus and Mathieu Moalic and Mateusz Zelent and Maciej Krawczyk and Paweł Gruszecki},
url = {https://doi.org/10.1063/5.0100594},
doi = {10.1063/5.0100594},
year = {2022},
date = {2022-09-08},
journal = {APL Materials},
volume = {10},
number = {9},
pages = {091101},
abstract = {Nontrivial magnetization textures, such as skyrmions, have become a driving force in the physics of magnetism. Furthermore, the utilization of magnetization textures is fueling the development of magnon-based technologies that could provide beyond-CMOS solutions. Here, using a self-developed spin wave (SW) excitation scheme, we selectively excite specific modes and investigate the scattering of SWs on nanodot hosting a Néel-type skyrmion and placed above a multimode waveguide. In particular, at low frequencies, we observe significant reflections from the imprint induced by the skyrmion upon the waveguide. As the frequency increases, the transmission increases as well; however, it is accompanied by scattering to other types of modes. Here, we observe a direct contribution of the skyrmion to the scattering process and various types of conversions of the incident SW modes into other modes quantized by width for both reflected and transmitted SWs. The utilization of imprinted magnetization textures in nonplanar systems to control SW flow can open new possibilities for developing SW-based circuits for ultralow-power signal processing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Nontrivial magnetization textures, such as skyrmions, have become a driving force in the physics of magnetism. Furthermore, the utilization of magnetization textures is fueling the development of magnon-based technologies that could provide beyond-CMOS solutions. Here, using a self-developed spin wave (SW) excitation scheme, we selectively excite specific modes and investigate the scattering of SWs on nanodot hosting a Néel-type skyrmion and placed above a multimode waveguide. In particular, at low frequencies, we observe significant reflections from the imprint induced by the skyrmion upon the waveguide. As the frequency increases, the transmission increases as well; however, it is accompanied by scattering to other types of modes. Here, we observe a direct contribution of the skyrmion to the scattering process and various types of conversions of the incident SW modes into other modes quantized by width for both reflected and transmitted SWs. The utilization of imprinted magnetization textures in nonplanar systems to control SW flow can open new possibilities for developing SW-based circuits for ultralow-power signal processing.
Szulc, Krzysztof; Tacchi, S; Hirreo-Rodríguez, A; Díaz, J; Gruszecki, Paweł; Graczyk, Piotr; and C Quirós,; Markó, D; Martín, J I; Vélez, M; Schmool, D S; Carlotti, G; Krawczyk, Maciej; Álvarez-Prado, L M
Reconfigurable Magnonic Crystals Based on Imprinted Magnetization Textures in Hard and Soft Dipolar-Coupled Bilayers Journal Article
In: ACS Nano, 2022.
@article{Szulc_Reconfigurable_Magnonic_Crystals,
title = {Reconfigurable Magnonic Crystals Based on Imprinted Magnetization Textures in Hard and Soft Dipolar-Coupled Bilayers},
author = {Krzysztof Szulc and S Tacchi and A Hirreo-Rodríguez and J Díaz and Paweł Gruszecki and Piotr Graczyk and and C Quirós and D Markó and J I Martín and M Vélez and D S Schmool and G Carlotti and Maciej Krawczyk and L M Álvarez-Prado},
doi = {https://doi.org/10.1021/acsnano.2c04256},
year = {2022},
date = {2022-08-31},
journal = {ACS Nano},
abstract = {Reconfigurable magnetization textures offer control of spin waves with promising properties for future low-power beyond-CMOS systems. However, materials with perpendicular magnetic anisotropy (PMA) suitable for stable magnetization-texture formation are characterized by high damping, which limits their applicability in magnonic devices. Here, we propose to overcome this limitation by using hybrid structures, i.e., a PMA layer magnetostatically coupled to a low-damping soft ferromagnetic film. We experimentally show that a periodic stripe-domain texture from a PMA layer is imprinted upon the soft layer and induces a nonreciprocal dispersion relation of the spin waves confined to the low-damping film. Moreover, an asymmetric bandgap features the spin-wave band diagram, which is a clear demonstration of collective spin-wave dynamics, a property characteristic for magnonic crystals with broken time-reversal symmetry. The composite character of the hybrid structure allows for stabilization of two magnetic states at remanence, with parallel and antiparallel orientation of net magnetization in hard and soft layers. The states can be switched using a low external magnetic field; therefore, the proposed system obtains an additional functionality of state reconfigurability. This study offers a link between reconfigurable magnetization textures and low-damping spin-wave dynamics, providing an opportunity to create miniaturized, programmable, and energy-efficient signal processing devices operating at high frequencies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Reconfigurable magnetization textures offer control of spin waves with promising properties for future low-power beyond-CMOS systems. However, materials with perpendicular magnetic anisotropy (PMA) suitable for stable magnetization-texture formation are characterized by high damping, which limits their applicability in magnonic devices. Here, we propose to overcome this limitation by using hybrid structures, i.e., a PMA layer magnetostatically coupled to a low-damping soft ferromagnetic film. We experimentally show that a periodic stripe-domain texture from a PMA layer is imprinted upon the soft layer and induces a nonreciprocal dispersion relation of the spin waves confined to the low-damping film. Moreover, an asymmetric bandgap features the spin-wave band diagram, which is a clear demonstration of collective spin-wave dynamics, a property characteristic for magnonic crystals with broken time-reversal symmetry. The composite character of the hybrid structure allows for stabilization of two magnetic states at remanence, with parallel and antiparallel orientation of net magnetization in hard and soft layers. The states can be switched using a low external magnetic field; therefore, the proposed system obtains an additional functionality of state reconfigurability. This study offers a link between reconfigurable magnetization textures and low-damping spin-wave dynamics, providing an opportunity to create miniaturized, programmable, and energy-efficient signal processing devices operating at high frequencies.
Gołębiewski, Mateusz; Gruszecki, Paweł; Krawczyk, Maciej
Self-Imaging Based Programmable Spin-Wave Lookup Tables Journal Article
In: Advanced Electronic Materials, pp. 2200373, 2022.
@article{golkebiewski2022self,
title = {Self-Imaging Based Programmable Spin-Wave Lookup Tables},
author = {Mateusz Gołębiewski and Paweł Gruszecki and Maciej Krawczyk
},
doi = {https://doi.org/10.1002/aelm.202200373},
year = {2022},
date = {2022-07-21},
urldate = {2022-07-21},
journal = {Advanced Electronic Materials},
pages = {2200373},
abstract = {Inclusion of spin waves into the computing paradigm, where complementary metal-oxide-semiconductor devices are still at the fore, is now a challenge for scientists around the world. In this work, a wave phenomenon that has not yet been used in magnonics-self-imaging, also known as the Talbot effect, to design and simulate the operation of interference systems that perform logic functions on spin waves in thin ferromagnetic multimode waveguides is utilized. Lookup tables operating in this way are characterized by high programmability and scalability; thanks to which they are promising for their implementation in field-programmable gate arrays circuits, where multiple logic realizations can be obtained.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Inclusion of spin waves into the computing paradigm, where complementary metal-oxide-semiconductor devices are still at the fore, is now a challenge for scientists around the world. In this work, a wave phenomenon that has not yet been used in magnonics-self-imaging, also known as the Talbot effect, to design and simulate the operation of interference systems that perform logic functions on spin waves in thin ferromagnetic multimode waveguides is utilized. Lookup tables operating in this way are characterized by high programmability and scalability; thanks to which they are promising for their implementation in field-programmable gate arrays circuits, where multiple logic realizations can be obtained.
Gruszecki, Paweł; Guslienko, K Y; Lyubchanskii, I L; Krawczyk, Maciej
Inelastic Spin-Wave Beam Scattering by Edge-Localized Spin Waves in a Ferromagnetic Thin Film Journal Article
In: Phys. Rev. Appl., vol. 17, iss. 4, no. 15, pp. 044038, 2022.
@article{gruszecki2022inelastic,
title = {Inelastic Spin-Wave Beam Scattering by Edge-Localized Spin Waves in a Ferromagnetic Thin Film},
author = {Paweł Gruszecki and K Y Guslienko and I L Lyubchanskii and Maciej Krawczyk},
url = {https://link.aps.org/doi/10.1103/PhysRevApplied.17.044038},
doi = {10.1103/PhysRevApplied.17.044038},
year = {2022},
date = {2022-04-20},
urldate = {2022-04-20},
journal = {Phys. Rev. Appl.},
volume = {17},
number = {15},
issue = {4},
pages = {044038},
abstract = {Spin waves are promising chargeless information carriers for the future, energetically efficient beyond
CMOS systems. Among many advantages are the ease of achieving nonlinearity, the variety of possible interactions, and excitation types. Although the rapidly developing magnonic research has already
yielded impressive realizations, multimode nonlinear effects, particularly with propagating waves and their
nanoscale realizations, are still an open research problem. We theoretically study the dynamic interactions
of spin waves confined to the edge of a thin ferromagnetic film with the spin-wave beam incident at this
edge. We find inelastically scattered spin-wave beams at frequencies increased and decreased by the frequency of the edge spin-wave relative to the specularly reflected beam. We observe a strong dependence
of the angular shift of the inelastic scattered spin-wave beam on the edge-mode frequency, which allows
us to propose a magnonic demultiplexing of the signal encoded in spin waves propagating along the edge.
Since dynamic magnetostatic interactions, which are ubiquitous in the spin-wave dynamics, are decisive
in this process, this indicates the possibility of implementing the presented effects in other configurations
and their use in magnonic systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Spin waves are promising chargeless information carriers for the future, energetically efficient beyond
CMOS systems. Among many advantages are the ease of achieving nonlinearity, the variety of possible interactions, and excitation types. Although the rapidly developing magnonic research has already
yielded impressive realizations, multimode nonlinear effects, particularly with propagating waves and their
nanoscale realizations, are still an open research problem. We theoretically study the dynamic interactions
of spin waves confined to the edge of a thin ferromagnetic film with the spin-wave beam incident at this
edge. We find inelastically scattered spin-wave beams at frequencies increased and decreased by the frequency of the edge spin-wave relative to the specularly reflected beam. We observe a strong dependence
of the angular shift of the inelastic scattered spin-wave beam on the edge-mode frequency, which allows
us to propose a magnonic demultiplexing of the signal encoded in spin waves propagating along the edge.
Since dynamic magnetostatic interactions, which are ubiquitous in the spin-wave dynamics, are decisive
in this process, this indicates the possibility of implementing the presented effects in other configurations
and their use in magnonic systems.
CMOS systems. Among many advantages are the ease of achieving nonlinearity, the variety of possible interactions, and excitation types. Although the rapidly developing magnonic research has already
yielded impressive realizations, multimode nonlinear effects, particularly with propagating waves and their
nanoscale realizations, are still an open research problem. We theoretically study the dynamic interactions
of spin waves confined to the edge of a thin ferromagnetic film with the spin-wave beam incident at this
edge. We find inelastically scattered spin-wave beams at frequencies increased and decreased by the frequency of the edge spin-wave relative to the specularly reflected beam. We observe a strong dependence
of the angular shift of the inelastic scattered spin-wave beam on the edge-mode frequency, which allows
us to propose a magnonic demultiplexing of the signal encoded in spin waves propagating along the edge.
Since dynamic magnetostatic interactions, which are ubiquitous in the spin-wave dynamics, are decisive
in this process, this indicates the possibility of implementing the presented effects in other configurations
and their use in magnonic systems.
Dhiman, A K; Gieniusz, R; Gruszecki, Paweł; Kisielewski, J; Matczak, M; Kurant, Z; Sveklo, I; Guzowska, U; Tekielak, M; Stobiecki, F; Maziewski, A
Magnetization statics and dynamics in (Ir/Co/Pt)6 multilayers with Dzyaloshinskii–Moriya interaction Journal Article
In: AIP Advances, vol. 12, no. 4, pp. 045007, 2022.
@article{Dhiman2022DMI,
title = {Magnetization statics and dynamics in (Ir/Co/Pt)6 multilayers with Dzyaloshinskii–Moriya interaction},
author = {A K Dhiman and R Gieniusz and Paweł Gruszecki and J Kisielewski and M Matczak and Z Kurant and I Sveklo and U Guzowska and M Tekielak and F Stobiecki and A Maziewski
},
doi = {https://doi.org/10.1063/9.0000339},
year = {2022},
date = {2022-04-04},
urldate = {2022-04-04},
journal = {AIP Advances},
volume = {12},
number = {4},
pages = {045007},
abstract = {Magnetic multilayers of (Ir/Co/Pt)6 with interfacial Dzyaloshinskii-Moriya interaction (IDMI) were deposited by magnetron sputtering with Co thickness d=1.8 nm. Exploiting magneto-optical Kerr effect in longitudinal mode microscopy, magnetic force microscopy, and vibrating sample magnetometry, the magnetic field-driven evolution of domain structures and magnetization hysteresis loops have been studied. The existence of weak stripe domains structure was deduced – tens micrometers size domains with in-plane “core” magnetization modulated by hundred of nanometers domains with out-of-plane magnetization. Micromagnetic simulations interpreted such magnetization distribution. Quantitative evaluation of IDMI was carried out using Brillouin light scattering (BLS) spectroscopy as the difference between Stokes and anti-Stokes peak frequencies Δf. Due to the additive nature of IDMI, the asymmetric combination of Ir and Pt covers led to large values of effective IDMI energy density Deff. It was found that Stokes and anti-Stokes frequencies as well as Δf, measured as a function of in-plane applied magnetic field, show hysteresis. These results are explained under the consideration of the influence of IDMI on the dynamics of the in-plane magnetized “core” with weak stripe domains},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Magnetic multilayers of (Ir/Co/Pt)6 with interfacial Dzyaloshinskii-Moriya interaction (IDMI) were deposited by magnetron sputtering with Co thickness d=1.8 nm. Exploiting magneto-optical Kerr effect in longitudinal mode microscopy, magnetic force microscopy, and vibrating sample magnetometry, the magnetic field-driven evolution of domain structures and magnetization hysteresis loops have been studied. The existence of weak stripe domains structure was deduced – tens micrometers size domains with in-plane “core” magnetization modulated by hundred of nanometers domains with out-of-plane magnetization. Micromagnetic simulations interpreted such magnetization distribution. Quantitative evaluation of IDMI was carried out using Brillouin light scattering (BLS) spectroscopy as the difference between Stokes and anti-Stokes peak frequencies Δf. Due to the additive nature of IDMI, the asymmetric combination of Ir and Pt covers led to large values of effective IDMI energy density Deff. It was found that Stokes and anti-Stokes frequencies as well as Δf, measured as a function of in-plane applied magnetic field, show hysteresis. These results are explained under the consideration of the influence of IDMI on the dynamics of the in-plane magnetized “core” with weak stripe domains
Sobucki, Krzysztof; Gruszecki, Paweł; Rychły, Justyna; Krawczyk, Maciej
Control of the Phase of Reflected Spin Waves From Magnonic Gires–Tournois Interferometer of Subwavelength Width Journal Article
In: IEEE Transactions on Magnetics, vol. 58, pp. 1-5, 2022, ISBN: 0018-9464.
@article{Sobucki_2022_GTI,
title = {Control of the Phase of Reflected Spin Waves From Magnonic Gires–Tournois Interferometer of Subwavelength Width},
author = {Krzysztof Sobucki and Paweł Gruszecki and Justyna Rychły and Maciej Krawczyk},
doi = {10.1109/TMAG.2021.3088298},
isbn = {0018-9464},
year = {2022},
date = {2022-02-01},
urldate = {2022-02-01},
journal = {IEEE Transactions on Magnetics},
volume = {58},
pages = {1-5},
abstract = {The phase is one of the fundamental properties of a wave that allows to control interference effects and can be used to efficiently encode information. We examine numerically a magnonic resonator of the Gires–Tournois interferometer type, which enables the control of the phase of spin waves (SWs) reflected from the edge of the ferromagnetic film. The considered interferometer consists of a Py thin film and a thin, narrow Py stripe placed above its edge, both coupled magnetostatically. We show that the resonances and the phase of the reflected SWs are sensitive for a variation of the geometrical parameters of this bi-layered part of the system. The high sensitivity to film, stripe, and non-magnetic spacer thicknesses offers a prospect for developing magnonic metasurfaces and sensors.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The phase is one of the fundamental properties of a wave that allows to control interference effects and can be used to efficiently encode information. We examine numerically a magnonic resonator of the Gires–Tournois interferometer type, which enables the control of the phase of spin waves (SWs) reflected from the edge of the ferromagnetic film. The considered interferometer consists of a Py thin film and a thin, narrow Py stripe placed above its edge, both coupled magnetostatically. We show that the resonances and the phase of the reflected SWs are sensitive for a variation of the geometrical parameters of this bi-layered part of the system. The high sensitivity to film, stripe, and non-magnetic spacer thicknesses offers a prospect for developing magnonic metasurfaces and sensors.
Gołębiewski, Mateusz; Gruszecki, Paweł; Krawczyk, Maciej
Self-imaging of spin waves in thin, multimodeferromagnetic waveguides Journal Article
In: IEEE Transactions on Magnetics, vol. 58, iss. 8, no. 8, pp. 1-5, 2022.
@article{gol_2022_talbot,
title = {Self-imaging of spin waves in thin, multimodeferromagnetic waveguides},
author = {Mateusz Gołębiewski and Paweł Gruszecki and Maciej Krawczyk
},
doi = {10.1109/TMAG.2022.3140280},
year = {2022},
date = {2022-01-04},
urldate = {2022-01-01},
journal = {IEEE Transactions on Magnetics},
volume = {58},
number = {8},
issue = {8},
pages = {1-5},
abstract = {Self-imaging of waves is an intriguing andspectacular effect. The phenomenon was first observedfor light in 1836 by Henry Fox Talbot and to this dayis the subject of research in many areas of physics,for various types of waves and in terms of differentapplications. This paper is a Talbot-effect study for spinwaves in systems composed of a thin, ferromagneticwaveguide with a series of single-mode sources of spinwaves flowing into it. The proposed systems are studiedwith the use of micromagnetic simulations, and the spinwave self-imaging dependencies on many parameters areexamined. We formulated conditions required for theformation of self-images and suitable for experimentalrealization. The results of the research form the basis forthe further development of self-imaging-based magnonicdevices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-imaging of waves is an intriguing andspectacular effect. The phenomenon was first observedfor light in 1836 by Henry Fox Talbot and to this dayis the subject of research in many areas of physics,for various types of waves and in terms of differentapplications. This paper is a Talbot-effect study for spinwaves in systems composed of a thin, ferromagneticwaveguide with a series of single-mode sources of spinwaves flowing into it. The proposed systems are studiedwith the use of micromagnetic simulations, and the spinwave self-imaging dependencies on many parameters areexamined. We formulated conditions required for theformation of self-images and suitable for experimentalrealization. The results of the research form the basis forthe further development of self-imaging-based magnonicdevices.
2021
Gruszecki, Paweł; Mruczkiewicz, Michał
The 2021 roadmap for noncollinear magnonics Journal Article
In: Solid State Physics, 2021, ISSN: 0081-1947.
@article{Mruczkiewicz2021,
title = {The 2021 roadmap for noncollinear magnonics},
author = {Paweł Gruszecki and Michał Mruczkiewicz},
doi = {https://doi.org/10.1016/bs.ssp.2021.09.001},
issn = {0081-1947},
year = {2021},
date = {2021-10-26},
urldate = {2021-10-26},
journal = {Solid State Physics},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Sobucki, Krzysztof; Śmigaj, Wojciech; Rychły, Justyna; Krawczyk, Maciej; Gruszecki, Paweł
Resonant subwavelength control of the phase of spin waves reflected from a Gires–Tournois interferometer Journal Article
In: Sci. Rep., vol. 11, no. 1, pp. 4428, 2021.
@article{sobucki_resonant_2021,
title = {Resonant subwavelength control of the phase of spin waves reflected from a Gires–Tournois interferometer},
author = {Krzysztof Sobucki and Wojciech Śmigaj and Justyna Rychły and Maciej Krawczyk and Paweł Gruszecki},
url = {https://www.nature.com/articles/s41598-021-83307-9},
doi = {10.1038/s41598-021-83307-9},
year = {2021},
date = {2021-02-24},
urldate = {2021-02-24},
journal = {Sci. Rep.},
volume = {11},
number = {1},
pages = {4428},
abstract = {Subwavelength resonant elements are essential building blocks of metamaterials and metasurfaces, which have revolutionized photonics. Despite similarities between different wave phenomena, other types of interactions can make subwavelength coupling significantly distinct; its investigation in their context is therefore of interest both from the physics and applications perspective. In this work, we demonstrate a fully magnonic Gires–Tournois interferometer based on a subwavelength resonator made of a narrow ferromagnetic stripe lying above the edge of a ferromagnetic film. The bilayer formed by the stripe and the film underneath supports two propagative spin-wave modes, one strongly coupled with spin waves propagating in the rest of the film and another almost completely reflected at the ends of the bilayer. When the Fabry–Perot resonance conditions for this mode are satisfied, the weak coupling between both modes is sufficient to achieve high sensitivity of the phase of waves reflected from the resonator to the stripe width and, more interestingly, also to the stripe-film separation. Such spin-wave phase manipulation capabilities are a prerequisite for the design of spin-wave metasurfaces and may stimulate development of magnonic logic devices and sensors detecting magnetic nanoparticles.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Subwavelength resonant elements are essential building blocks of metamaterials and metasurfaces, which have revolutionized photonics. Despite similarities between different wave phenomena, other types of interactions can make subwavelength coupling significantly distinct; its investigation in their context is therefore of interest both from the physics and applications perspective. In this work, we demonstrate a fully magnonic Gires–Tournois interferometer based on a subwavelength resonator made of a narrow ferromagnetic stripe lying above the edge of a ferromagnetic film. The bilayer formed by the stripe and the film underneath supports two propagative spin-wave modes, one strongly coupled with spin waves propagating in the rest of the film and another almost completely reflected at the ends of the bilayer. When the Fabry–Perot resonance conditions for this mode are satisfied, the weak coupling between both modes is sufficient to achieve high sensitivity of the phase of waves reflected from the resonator to the stripe width and, more interestingly, also to the stripe-film separation. Such spin-wave phase manipulation capabilities are a prerequisite for the design of spin-wave metasurfaces and may stimulate development of magnonic logic devices and sensors detecting magnetic nanoparticles.
Gruszecki, Paweł; Lyubchanskii, I L; Guslienko, K Y; Krawczyk, Maciej
Local non-linear excitation of sub-100 nm bulk-type spin waves by edge-localized spin waves in magnetic films Journal Article
In: Appl. Phys. Lett., vol. 118, no. 6, pp. 062408, 2021.
@article{doi:10.1063/5.0041030,
title = {Local non-linear excitation of sub-100 nm bulk-type spin waves by edge-localized spin waves in magnetic films},
author = {Paweł Gruszecki and I L Lyubchanskii and K Y Guslienko and Maciej Krawczyk},
doi = {10.1063/5.0041030},
year = {2021},
date = {2021-02-11},
journal = {Appl. Phys. Lett.},
volume = {118},
number = {6},
pages = {062408},
abstract = {The excitation of high-frequency short-wavelength spin waves is a challenge limiting the application of these propagating magnetization disturbances in information processing systems. We propose a method of local excitation of the high-frequency spin waves using the non-linear nature of magnetization dynamics. We demonstrate with numeric simulations that an edge-localized spin wave can be used to excite plane waves propagating obliquely from the film's edge at a doubled frequency and over twice shorter in wavelength. The excitation mechanism is a direct result of the ellipticity of the magnetic moment precession that is related to the edge-mode propagation. As a consequence, the magnetization component tangential to the equilibrium orientation oscillates with doubled temporal and spatial frequencies, which leads to efficient excitation of the plane spin waves. The threshold-less non-linear process of short-wavelength spin-wave excitation proposed in our study is promising for integration with an inductive or point-like spin-torque source of edge spin waves.
The research leading to these results received funding from the National Science Centre of Poland, Project No. 2019/35/D/ST3/03729. I.L.L. acknowledges support from a COST action under Project No. CA17123 MAGNETOFON. K.Y.G. acknowledges support from IKERBASQUE (the Basque Foundation for Science) and from the Spanish Ministerio de Ciencia, Innovacion y Universidades Grant No. PID2019-108075RB-C33/AEI/10.13039/501100011033. The simulations were partially performed at the Poznan Supercomputing and Networking Center (Grant No. 398).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The excitation of high-frequency short-wavelength spin waves is a challenge limiting the application of these propagating magnetization disturbances in information processing systems. We propose a method of local excitation of the high-frequency spin waves using the non-linear nature of magnetization dynamics. We demonstrate with numeric simulations that an edge-localized spin wave can be used to excite plane waves propagating obliquely from the film's edge at a doubled frequency and over twice shorter in wavelength. The excitation mechanism is a direct result of the ellipticity of the magnetic moment precession that is related to the edge-mode propagation. As a consequence, the magnetization component tangential to the equilibrium orientation oscillates with doubled temporal and spatial frequencies, which leads to efficient excitation of the plane spin waves. The threshold-less non-linear process of short-wavelength spin-wave excitation proposed in our study is promising for integration with an inductive or point-like spin-torque source of edge spin waves.
The research leading to these results received funding from the National Science Centre of Poland, Project No. 2019/35/D/ST3/03729. I.L.L. acknowledges support from a COST action under Project No. CA17123 MAGNETOFON. K.Y.G. acknowledges support from IKERBASQUE (the Basque Foundation for Science) and from the Spanish Ministerio de Ciencia, Innovacion y Universidades Grant No. PID2019-108075RB-C33/AEI/10.13039/501100011033. The simulations were partially performed at the Poznan Supercomputing and Networking Center (Grant No. 398).
The research leading to these results received funding from the National Science Centre of Poland, Project No. 2019/35/D/ST3/03729. I.L.L. acknowledges support from a COST action under Project No. CA17123 MAGNETOFON. K.Y.G. acknowledges support from IKERBASQUE (the Basque Foundation for Science) and from the Spanish Ministerio de Ciencia, Innovacion y Universidades Grant No. PID2019-108075RB-C33/AEI/10.13039/501100011033. The simulations were partially performed at the Poznan Supercomputing and Networking Center (Grant No. 398).
Träger, N; Gruszecki, Paweł; Lisiecki, F; Groß, F; Förster, J; Weigand, M; Głowiński, H; Kuświk, P; Dubowik, Janusz; Schütz, G; Krawczyk, Maciej; Gräfe, J
Real-Space Observation of Magnon Interaction with Driven Space-Time Crystals Journal Article
In: Phys. Rev. Lett., vol. 126, pp. 057201, 2021.
@article{PhysRevLett.126.057201,
title = {Real-Space Observation of Magnon Interaction with Driven Space-Time Crystals},
author = {N Träger and Paweł Gruszecki and F Lisiecki and F Groß and J Förster and M Weigand and H Głowiński and P Kuświk and Janusz Dubowik and G Schütz and Maciej Krawczyk and J Gräfe},
url = {https://doi.org/10.1103/PhysRevLett.126.057201},
doi = {10.1103/PhysRevLett.126.057201},
year = {2021},
date = {2021-02-03},
journal = {Phys. Rev. Lett.},
volume = {126},
pages = {057201},
abstract = {The concept of space-time crystals (STC), i.e., translational symmetry breaking in time and space, was recently proposed and experimentally demonstrated for quantum systems. Here, we transfer this concept to magnons and experimentally demonstrate a driven STC at room temperature. The STC is realized by strong homogeneous microwave pumping of a micron-sized permalloy (Py) stripe and is directly imaged by scanning transmission x-ray microscopy (STXM). For a fundamental understanding of the formation of the STC, micromagnetic simulations are carefully adapted to model the experimental findings. Beyond the mere generation of a STC, we observe the formation of a magnonic band structure due to back folding of modes at the STC’s Brillouin zone boundaries. We show interactions of magnons with the STC that appear as lattice scattering, which results in the generation of ultrashort spin waves (SW) down to 100-nm wavelengths that cannot be described by classical dispersion relations for linear SW excitation. We expect that room-temperature STCs will be useful to investigate nonlinear wave physics, as they can be easily generated and manipulated to control their spatial and temporal band structures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The concept of space-time crystals (STC), i.e., translational symmetry breaking in time and space, was recently proposed and experimentally demonstrated for quantum systems. Here, we transfer this concept to magnons and experimentally demonstrate a driven STC at room temperature. The STC is realized by strong homogeneous microwave pumping of a micron-sized permalloy (Py) stripe and is directly imaged by scanning transmission x-ray microscopy (STXM). For a fundamental understanding of the formation of the STC, micromagnetic simulations are carefully adapted to model the experimental findings. Beyond the mere generation of a STC, we observe the formation of a magnonic band structure due to back folding of modes at the STC’s Brillouin zone boundaries. We show interactions of magnons with the STC that appear as lattice scattering, which results in the generation of ultrashort spin waves (SW) down to 100-nm wavelengths that cannot be described by classical dispersion relations for linear SW excitation. We expect that room-temperature STCs will be useful to investigate nonlinear wave physics, as they can be easily generated and manipulated to control their spatial and temporal band structures.
Trager, N; Lisiecki, F; Lawitzki, R; Weigand, M; Głowiński, H; Schütz, G; Schmitz, G; Kuświk, P; Krawczyk, Maciej; Gräfe, J; Gruszecki, Paweł
Competing spin wave emission mechanisms revealed by time-resolved x-ray microscopy Journal Article
In: Phys. Rev. B, vol. 103, pp. 014430, 2021.
@article{PhysRevB.103.014430,
title = {Competing spin wave emission mechanisms revealed by time-resolved x-ray microscopy},
author = {N Trager and F Lisiecki and R Lawitzki and M Weigand and H Głowiński and G Schütz and G Schmitz and P Kuświk and Maciej Krawczyk and J Gräfe and Paweł Gruszecki},
url = {https://link.aps.org/doi/10.1103/PhysRevB.103.014430},
doi = {10.1103/PhysRevB.103.014430},
year = {2021},
date = {2021-01-19},
urldate = {2021-01-19},
journal = {Phys. Rev. B},
volume = {103},
pages = {014430},
abstract = {Spin wave emission and propagation in magnonic waveguides represent a highly promising alternative for beyond-CMOS computing. It is therefore all the more important to fully understand the underlying physics of the emission process. Here, we use time-resolved scanning transmission x-ray microscopy to directly image the formation process of the globally excited local emission of spin waves in a permalloy waveguide at the nanoscale. Thereby, we observe spin wave emission from the corner of the waveguide as well as from a local oscillation of a domain-wall-like structure within the waveguide. Additionally, an isofrequency contour analysis is used to fully explain the origin of quasicylindrical spin wave excitation from the corner and its concurrent nonreflection and nonrefraction at the domain interface. This study is complemented by micromagnetic simulations which perfectly fit the experimental findings. Thus, we clarify the fundamental question of the emission mechanisms in magnonic waveguides which lay the basis for future magnonic operations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Spin wave emission and propagation in magnonic waveguides represent a highly promising alternative for beyond-CMOS computing. It is therefore all the more important to fully understand the underlying physics of the emission process. Here, we use time-resolved scanning transmission x-ray microscopy to directly image the formation process of the globally excited local emission of spin waves in a permalloy waveguide at the nanoscale. Thereby, we observe spin wave emission from the corner of the waveguide as well as from a local oscillation of a domain-wall-like structure within the waveguide. Additionally, an isofrequency contour analysis is used to fully explain the origin of quasicylindrical spin wave excitation from the corner and its concurrent nonreflection and nonrefraction at the domain interface. This study is complemented by micromagnetic simulations which perfectly fit the experimental findings. Thus, we clarify the fundamental question of the emission mechanisms in magnonic waveguides which lay the basis for future magnonic operations.