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Al-Hamdo H, Wagner T, Lytvynenko Y, Kendzo G, Reimers S, Ruhwedel M, Yaqoob M, Vasyuchka VI, Pirro P, Sinova J, Kläui M, Jourdan M, Gomonay O, Weiler M. Coupling of Ferromagnetic and Antiferromagnetic Spin Dynamics in Mn_{2}Au/NiFe Thin Film Bilayers. PHYSICAL REVIEW LETTERS 2023; 131:046701. [PMID: 37566862 DOI: 10.1103/physrevlett.131.046701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/26/2023] [Indexed: 08/13/2023]
Abstract
We investigate magnetization dynamics of Mn_{2}Au/Py (Ni_{80}Fe_{20}) thin film bilayers using broadband ferromagnetic resonance (FMR) and Brillouin light scattering spectroscopy. Our bilayers exhibit two resonant modes with zero-field frequencies up to almost 40 GHz, far above the single-layer Py FMR. Our model calculations attribute these modes to the coupling of the Py FMR and the two antiferromagnetic resonance (AFMR) modes of Mn_{2}Au. The coupling strength is in the order of 1.6 T nm at room temperature for nm-thick Py. Our model reveals the dependence of the hybrid modes on the AFMR frequencies and interfacial coupling as well as the evanescent character of the spin waves that extend across the Mn_{2}Au/Py interface.
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Affiliation(s)
- Hassan Al-Hamdo
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Tobias Wagner
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Yaryna Lytvynenko
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
- Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, 03142 Kyiv, Ukraine
| | - Gutenberg Kendzo
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Sonka Reimers
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Moritz Ruhwedel
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Misbah Yaqoob
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Vitaliy I Vasyuchka
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Philipp Pirro
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Jairo Sinova
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Martin Jourdan
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Olena Gomonay
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Mathias Weiler
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
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Abstract
Nonreciprocity emerges in nature and in artificial objects from various physical origins, being widely utilized in contemporary technologies as exemplified by diode elements in electronics. While most of the nonreciprocal phenomena are realized by employing interfaces where the inversion symmetry is trivially lifted, nonreciprocal transport of photons, electrons, magnons, and possibly phonons also emerge in bulk crystals with broken space inversion and time reversal symmetries. Among them, directional propagation of bulk magnons (i.e., quanta of spin wave excitation) is attracting much attention nowadays for its potentially large nonreciprocity suitable for spintronic and spin-caloritronic applications. Here, we demonstrate nonreciprocal propagation of spin waves for the conical spin helix state in Cu2OSeO3 due to a combination of dipole and Dzyaloshinskii-Moriya interactions. The observed nonreciprocal spin dispersion smoothly connects to the hitherto known magnetochiral nonreciprocity in the field-induced collinear spin state; thus, all the spin phases show diode characteristics in this chiral insulator.
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Aqeel A, Sahliger J, Taniguchi T, Mändl S, Mettus D, Berger H, Bauer A, Garst M, Pfleiderer C, Back CH. Microwave Spectroscopy of the Low-Temperature Skyrmion State in Cu_{2}OSeO_{3}. PHYSICAL REVIEW LETTERS 2021; 126:017202. [PMID: 33480751 DOI: 10.1103/physrevlett.126.017202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
In the cubic chiral magnet Cu_{2}OSeO_{3} a low-temperature skyrmion state (LTS) and a concomitant tilted conical state are observed for magnetic fields parallel to ⟨100⟩. Here, we report on the dynamic resonances of these novel magnetic states. After promoting the nucleation of the LTS by means of field cycling, we apply broadband microwave spectroscopy in two experimental geometries that provide either predominantly in-plane or out-of-plane excitation. By comparing the results to linear spin-wave theory, we clearly identify resonant modes associated with the tilted conical state, the gyrational and breathing modes associated with the LTS, as well as the hybridization of the breathing mode with a dark octupole gyration mode mediated by the magnetocrystalline anisotropies. Most intriguingly, our findings suggest that under decreasing fields the hexagonal skyrmion lattice becomes unstable with respect to an oblique deformation, reflected in the formation of elongated skyrmions.
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Affiliation(s)
- Aisha Aqeel
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Jan Sahliger
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Takuya Taniguchi
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Stefan Mändl
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Denis Mettus
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Helmuth Berger
- École Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Andreas Bauer
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Markus Garst
- Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for quantum materials and technology, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | | | - Christian H Back
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), D-80799 München, Germany
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Pöllath S, Aqeel A, Bauer A, Luo C, Ryll H, Radu F, Pfleiderer C, Woltersdorf G, Back CH. Ferromagnetic Resonance with Magnetic Phase Selectivity by Means of Resonant Elastic X-Ray Scattering on a Chiral Magnet. PHYSICAL REVIEW LETTERS 2019; 123:167201. [PMID: 31702336 DOI: 10.1103/physrevlett.123.167201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Cubic chiral magnets, such as Cu_{2}OSeO_{3}, exhibit a variety of noncollinear spin textures, including a trigonal lattice of spin whirls, the so-called skyrmions. Using magnetic resonant elastic x-ray scattering (REXS) on a crystalline Bragg peak and its magnetic satellites while exciting the sample with magnetic fields at gigahertz frequencies, we probe the ferromagnetic resonance (FMR) modes of these spin textures by means of the scattered intensity. Most notably, the three eigenmodes of the skyrmion lattice are detected with large sensitivity. As this novel technique, which we label REXS FMR, is carried out at distinct positions in reciprocal space, it allows us to distinguish contributions originating from different magnetic states, providing information on the precise character, weight, and mode mixing as a prerequisite of tailored excitations for applications.
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Affiliation(s)
- S Pöllath
- Institut für Experimentelle Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - A Aqeel
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - A Bauer
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - C Luo
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
- Helmholtz-Zentrum Berlin für Materialien and Energie, D-12489 Berlin, Germany
| | - H Ryll
- Helmholtz-Zentrum Berlin für Materialien and Energie, D-12489 Berlin, Germany
| | - F Radu
- Helmholtz-Zentrum Berlin für Materialien and Energie, D-12489 Berlin, Germany
| | - C Pfleiderer
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, D-80799 München, Germany
| | - G Woltersdorf
- Institut für Physik, Universität Halle-Wittenberg, D-06120 Halle (Saale), Germany
| | - C H Back
- Institut für Experimentelle Physik, Universität Regensburg, D-93040 Regensburg, Germany
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, D-80799 München, Germany
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Maier-Flaig H, Goennenwein STB, Ohshima R, Shiraishi M, Gross R, Huebl H, Weiler M. Note: Derivative divide, a method for the analysis of broadband ferromagnetic resonance in the frequency domain. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:076101. [PMID: 30068101 DOI: 10.1063/1.5045135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Broadband ferromagnetic resonance (bbFMR) spectroscopy is an established experimental tool to quantify magnetic properties. Due to frequency-dependent transmission of the microwave setup, bbFMR measurements in the frequency domain require a suitable background removal method. Here, we present a measurement and data analysis protocol that allows us to perform quantitative frequency-swept bbFMR measurements without the need for a calibration of the microwave setup. We furthermore compare the results of the proposed frequency space analysis and a conventional analysis in field-space of bbFMR data obtained from a permalloy thin film. The very good agreement of the extracted parameters using the two methods shows the reliability of our method.
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Affiliation(s)
- Hannes Maier-Flaig
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany
| | | | - Ryo Ohshima
- Department of Electronic Science and Engineering, Kyoto University, Kyoto, Japan
| | - Masashi Shiraishi
- Department of Electronic Science and Engineering, Kyoto University, Kyoto, Japan
| | - Rudolf Gross
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany
| | - Hans Huebl
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany
| | - Mathias Weiler
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany
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Zhang X, Xia J, Zhou Y, Liu X, Zhang H, Ezawa M. Skyrmion dynamics in a frustrated ferromagnetic film and current-induced helicity locking-unlocking transition. Nat Commun 2017; 8:1717. [PMID: 29167418 PMCID: PMC5700181 DOI: 10.1038/s41467-017-01785-w] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 10/13/2017] [Indexed: 11/17/2022] Open
Abstract
The helicity-orbital coupling is an intriguing feature of magnetic skyrmions in frustrated magnets. Here we explore the skyrmion dynamics in a frustrated magnet based on the J1-J2-J3 classical Heisenberg model explicitly by including the dipole-dipole interaction. The skyrmion energy acquires a helicity dependence due to the dipole-dipole interaction, resulting in the current-induced translational motion with a fixed helicity. The lowest-energy states are the degenerate Bloch-type states, which can be used for building the binary memory. By increasing the driving current, the helicity locking-unlocking transition occurs, where the translational motion changes to the rotational motion. Furthermore, we demonstrate that two skyrmions can spontaneously form a bound state. The separation of the bound state forced by a driving current is also studied. In addition, we show the annihilation of a pair of skyrmion and antiskyrmion. Our results reveal the distinctive frustrated skyrmions may enable viable applications in topological magnetism. Exploring the helicity-orbital coupling induced skyrmion properties is essential for the spintronic applications. Here the authors report the current controlled skyrmions and antiskyrmions dynamics with locking-unlocking helicity in frustrated magnets by including the dipole-dipole interaction in their model.
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Affiliation(s)
- Xichao Zhang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Jing Xia
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China.
| | - Xiaoxi Liu
- Department of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553, Japan
| | - Han Zhang
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Motohiko Ezawa
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-8656, Japan.
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