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Barman A, Gubbiotti G, Ladak S, Adeyeye AO, Krawczyk M, Gräfe J, Adelmann C, Cotofana S, Naeemi A, Vasyuchka VI, Hillebrands B, Nikitov SA, Yu H, Grundler D, Sadovnikov AV, Grachev AA, Sheshukova SE, Duquesne JY, Marangolo M, Csaba G, Porod W, Demidov VE, Urazhdin S, Demokritov SO, Albisetti E, Petti D, Bertacco R, Schultheiss H, Kruglyak VV, Poimanov VD, Sahoo S, Sinha J, Yang H, Münzenberg M, Moriyama T, Mizukami S, Landeros P, Gallardo RA, Carlotti G, Kim JV, Stamps RL, Camley RE, Rana B, Otani Y, Yu W, Yu T, Bauer GEW, Back C, Uhrig GS, Dobrovolskiy OV, Budinska B, Qin H, van Dijken S, Chumak AV, Khitun A, Nikonov DE, Young IA, Zingsem BW, Winklhofer M. The 2021 Magnonics Roadmap. J Phys Condens Matter 2021; 33:413001. [PMID: 33662946 DOI: 10.1088/1361-648x/abec1a] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 03/04/2021] [Indexed: 05/26/2023]
Abstract
Magnonics is a budding research field in nanomagnetism and nanoscience that addresses the use of spin waves (magnons) to transmit, store, and process information. The rapid advancements of this field during last one decade in terms of upsurge in research papers, review articles, citations, proposals of devices as well as introduction of new sub-topics prompted us to present the first roadmap on magnonics. This is a collection of 22 sections written by leading experts in this field who review and discuss the current status besides presenting their vision of future perspectives. Today, the principal challenges in applied magnonics are the excitation of sub-100 nm wavelength magnons, their manipulation on the nanoscale and the creation of sub-micrometre devices using low-Gilbert damping magnetic materials and its interconnections to standard electronics. To this end, magnonics offers lower energy consumption, easier integrability and compatibility with CMOS structure, reprogrammability, shorter wavelength, smaller device features, anisotropic properties, negative group velocity, non-reciprocity and efficient tunability by various external stimuli to name a few. Hence, despite being a young research field, magnonics has come a long way since its early inception. This roadmap asserts a milestone for future emerging research directions in magnonics, and hopefully, it will inspire a series of exciting new articles on the same topic in the coming years.
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Affiliation(s)
- Anjan Barman
- Department of Condensed Matter Physics and Material Sciences, S N Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700106, India
| | - Gianluca Gubbiotti
- Istituto Officina dei Materiali del Consiglio nazionale delle Ricerche (IOM-CNR), Perugia, Italy
| | - S Ladak
- School of Physics and Astronomy, Cardiff University, United Kingdom
| | - A O Adeyeye
- Department of Physics, University of Durham, United Kingdom
| | - M Krawczyk
- Adam Mickiewicz University, Poznan, Poland
| | - J Gräfe
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | | | - S Cotofana
- Delft University of Technology, The Netherlands
| | - A Naeemi
- Georgia Institute of Technology, United States of America
| | - V I Vasyuchka
- Department of Physics and State Research Center OPTIMAS, Technische Universität Kaiserslautern (TUK), Kaiserslautern, Germany
| | - B Hillebrands
- Department of Physics and State Research Center OPTIMAS, Technische Universität Kaiserslautern (TUK), Kaiserslautern, Germany
| | - S A Nikitov
- Kotelnikov Institute of Radioengineering and Electronics, Moscow, Russia
| | - H Yu
- Fert Beijing Institute, BDBC, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brian Computing, Beihang University, People's Republic of China
| | - D Grundler
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), Institute of Electrical and Micro Engineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - A V Sadovnikov
- Kotelnikov Institute of Radioengineering and Electronics, Moscow, Russia
- Laboratory 'Magnetic Metamaterials', Saratov State University, Saratov, Russia
| | - A A Grachev
- Kotelnikov Institute of Radioengineering and Electronics, Moscow, Russia
- Laboratory 'Magnetic Metamaterials', Saratov State University, Saratov, Russia
| | - S E Sheshukova
- Kotelnikov Institute of Radioengineering and Electronics, Moscow, Russia
- Laboratory 'Magnetic Metamaterials', Saratov State University, Saratov, Russia
| | - J-Y Duquesne
- Institut des NanoSciences de Paris, Sorbonne University, CNRS, Paris, France
| | - M Marangolo
- Institut des NanoSciences de Paris, Sorbonne University, CNRS, Paris, France
| | - G Csaba
- Pázmány University, Budapest, Hungary
| | - W Porod
- University of Notre Dame, IN, United States of America
| | - V E Demidov
- Institute for Applied Physics, University of Muenster, Muenster, Germany
| | - S Urazhdin
- Department of Physics, Emory University, Atlanta, United States of America
| | - S O Demokritov
- Institute for Applied Physics, University of Muenster, Muenster, Germany
| | | | - D Petti
- Polytechnic University of Milan, Italy
| | | | - H Schultheiss
- Helmholtz-Center Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Germany
- Technische Universität Dresden, Germany
| | | | | | - S Sahoo
- Department of Condensed Matter Physics and Material Sciences, S N Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700106, India
| | - J Sinha
- Department of Physics and Nanotechnology, SRM Institute of Science and Technology, Kattankulathur, India
| | - H Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore
| | - M Münzenberg
- Institute of Physics, University of Greifswald, Greifswald, Germany
| | - T Moriyama
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, Japan
- Centre for Spintronics Research Network, Japan
| | - S Mizukami
- Centre for Spintronics Research Network, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, Japan
| | - P Landeros
- Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
| | - R A Gallardo
- Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
| | - G Carlotti
- Dipartimento di Fisica e Geologia, University of Perugia, Perugia, Italy
- CNR Instituto Nanoscienze, Modena, Italy
| | - J-V Kim
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, Palaiseau, France
| | - R L Stamps
- Department of Physics and Astronomy, University of Manitoba, Canada
| | - R E Camley
- Center for Magnetism and Magnetic Nanostructures, University of Colorado, Colorado Springs, United States of America
| | | | - Y Otani
- RIKEN, Japan
- Institute for Solid State Physics (ISSP), University of Tokyo, Japan
| | - W Yu
- Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - T Yu
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - G E W Bauer
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, Japan
- Zernike Institute for Advanced Materials, Groningen University, The Netherlands
| | - C Back
- Technical University Munich, Germany
| | - G S Uhrig
- Technical University Dortmund, Germany
| | | | - B Budinska
- Faculty of Physics, University of Vienna, Vienna, Austria
| | - H Qin
- Department of Applied Physics, School of Science, Aalto University, Finland
| | - S van Dijken
- Department of Applied Physics, School of Science, Aalto University, Finland
| | - A V Chumak
- Faculty of Physics, University of Vienna, Vienna, Austria
| | - A Khitun
- University of California Riverside, United States of America
| | - D E Nikonov
- Components Research, Intel, Hillsboro, Oregon, United States of America
| | - I A Young
- Components Research, Intel, Hillsboro, Oregon, United States of America
| | - B W Zingsem
- The University of Duisburg-Essen, CENIDE, Germany
| | - M Winklhofer
- The Carl von Ossietzky University of Oldenburg, Germany
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Harder M, Yang Y, Yao BM, Yu CH, Rao JW, Gui YS, Stamps RL, Hu CM. Level Attraction Due to Dissipative Magnon-Photon Coupling. Phys Rev Lett 2018; 121:137203. [PMID: 30312103 DOI: 10.1103/physrevlett.121.137203] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/03/2018] [Indexed: 06/08/2023]
Abstract
We report dissipative magnon-photon coupling caused by the cavity Lenz effect, where the magnons in a magnet induce a rf current in the cavity, leading to a cavity backaction that impedes the magnetization dynamics. This effect is revealed in our experiment as level attraction with a coalescence of hybridized magnon-photon modes, which is distinctly different from level repulsion with mode anticrossing caused by coherent magnon-photon coupling. We develop a method to control the interpolation of coherent and dissipative magnon-photon coupling, and observe a matching condition where the two effects cancel. Our work sheds light on the so-far hidden side of magnon-photon coupling, opening a new avenue for controlling and utilizing light-matter interactions.
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Affiliation(s)
- M Harder
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - Y Yang
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - B M Yao
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - C H Yu
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
- Jiangsu Key Laboratory of ASIC Design, Nantong University, Nantong 226019, China
| | - J W Rao
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - Y S Gui
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - R L Stamps
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - C-M Hu
- Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
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Goncalves FJT, Paterson GW, McGrouther D, Drysdale T, Togawa Y, Schmool DS, Stamps RL. Probing microwave fields and enabling in-situ experiments in a transmission electron microscope. Sci Rep 2017; 7:11064. [PMID: 28894134 PMCID: PMC5593874 DOI: 10.1038/s41598-017-11009-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/15/2017] [Indexed: 12/04/2022] Open
Abstract
A technique is presented whereby the performance of a microwave device is evaluated by mapping local field distributions using Lorentz transmission electron microscopy (L-TEM). We demonstrate the method by measuring the polarisation state of the electromagnetic fields produced by a microstrip waveguide as a function of its gigahertz operating frequency. The forward and backward propagating electromagnetic fields produced by the waveguide, in a specimen-free experiment, exert Lorentz forces on the propagating electron beam. Importantly, in addition to the mapping of dynamic fields, this novel method allows detection of effects of microwave fields on specimens, such as observing ferromagnetic materials at resonance.
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Affiliation(s)
- F J T Goncalves
- Department of Physics and Electronics, Osaka Prefecture University, Osaka, 599-8570, Japan.
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - G W Paterson
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - D McGrouther
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - T Drysdale
- Department of Engineering and Innovation, The Open University, Milton Keynes, MK7 6AA, UK
| | - Y Togawa
- Department of Physics and Electronics, Osaka Prefecture University, Osaka, 599-8570, Japan
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - D S Schmool
- Groupe d'Etude de la Matière Condensée GEMaC, CNRS (UMR 8635), Université de Versailles/Saint-Quentin-en-Yvelines, 45 Avenue des États-Unis, 78035, Versailles, France
| | - R L Stamps
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
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Leonov AO, Togawa Y, Monchesky TL, Bogdanov AN, Kishine J, Kousaka Y, Miyagawa M, Koyama T, Akimitsu J, Koyama T, Harada K, Mori S, McGrouther D, Lamb R, Krajnak M, McVitie S, Stamps RL, Inoue K. Chiral Surface Twists and Skyrmion Stability in Nanolayers of Cubic Helimagnets. Phys Rev Lett 2016; 117:087202. [PMID: 27588877 DOI: 10.1103/physrevlett.117.087202] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Indexed: 06/06/2023]
Abstract
Theoretical analysis and Lorentz transmission electron microscopy (LTEM) investigations in an FeGe wedge demonstrate that chiral twists arising near the surfaces of noncentrosymmetric ferromagnets [Meynell et al., Phys. Rev. B 90, 014406 (2014)] provide a stabilization mechanism for magnetic Skyrmion lattices and helicoids in cubic helimagnet nanolayers. The magnetic phase diagram obtained for freestanding cubic helimagnet nanolayers shows that magnetization processes differ fundamentally from those in bulk cubic helimagnets and are characterized by the first-order transitions between modulated phases. LTEM investigations exhibit a series of hysteretic transformation processes among the modulated phases, which results in the formation of the multidomain patterns.
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Affiliation(s)
- A O Leonov
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- IFW Dresden, Postfach 270016, D-01171 Dresden, Germany
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Y Togawa
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- JST, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 333-0012, Japan
| | - T L Monchesky
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada
| | - A N Bogdanov
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- IFW Dresden, Postfach 270016, D-01171 Dresden, Germany
| | - J Kishine
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- The Open University of Japan, Chiba 261-8586, Japan
| | - Y Kousaka
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - M Miyagawa
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - T Koyama
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - J Akimitsu
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Ts Koyama
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
| | - K Harada
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
| | - S Mori
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
| | - D McGrouther
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - R Lamb
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - M Krajnak
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S McVitie
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - R L Stamps
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - K Inoue
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- IAMR, Facility of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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Abstract
Recent studies on surface reflection illustrate how light beams can be laterally shifted from the position predicted by geometrical optics, the so called Goos-Hänchen effect. In antiferromagnets this shifts can be controlled with an external magnetic field. We show that a configuration in which spins cant in response to applied magnetic fields enhance possibilities of field controlled shifts. Moreover, we show that nonreciprocal displacements are possible, for both oblique and normal incidence, due to inherent nonreciprocity of the polariton phase with respect to the propagation direction. In the absence of an external field, reciprocal displacements occur.
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Abstract
Lithographic processing and film growth technologies are continuing to advance, so that it is now possible to create patterned ferroic materials consisting of arrays of sub-1 μm elements with high definition. Some of the most fascinating behaviour of these arrays can be realised by exploiting interactions between the individual elements to create new functionality. The properties of these artificial ferroic systems differ strikingly from those of their constituent components, with novel emergent behaviour arising from the collective dynamics of the interacting elements, which are arranged in specific designs and can be activated by applying magnetic or electric fields. We first focus on artificial spin systems consisting of arrays of dipolar-coupled nanomagnets and, in particular, review the field of artificial spin ice, which demonstrates a wide range of fascinating phenomena arising from the frustration inherent in particular arrangements of nanomagnets, including emergent magnetic monopoles, domains of ordered macrospins, and novel avalanche behaviour. We outline how demagnetisation protocols have been employed as an effective thermal anneal in an attempt to reach the ground state, comment on phenomena that arise in thermally activated systems and discuss strategies for selectively generating specific configurations using applied magnetic fields. We then move on from slow field and temperature driven dynamics to high frequency phenomena, discussing spinwave excitations in the context of magnonic crystals constructed from arrays of patterned magnetic elements. At high frequencies, these arrays are studied in terms of potential applications including magnetic logic, linear and non-linear microwave optics, and fast, efficient switching, and we consider the possibility to create tunable magnonic crystals with artificial spin ice. Finally, we discuss how functional ferroic composites can be incorporated to realise magnetoelectric effects. Specifically, we discuss artificial multiferroics (or multiferroic composites), which hold promise for new applications that involve electric field control of magnetism, or electric and magnetic field responsive devices for high frequency integrated circuit design in microwave and terahertz signal processing. We close with comments on how enhanced functionality can be realised through engineering of nanostructures with interacting ferroic components, creating opportunities for novel spin electronic devices that, for example, make use of the transport of magnetic charges, thermally activated elements, and reprogrammable nanomagnet systems.
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Affiliation(s)
- L J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
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Budrikis Z, Morgan JP, Akerman J, Stein A, Politi P, Langridge S, Marrows CH, Stamps RL. Disorder strength and field-driven ground state domain formation in artificial spin ice: experiment, simulation, and theory. Phys Rev Lett 2012; 109:037203. [PMID: 22861890 DOI: 10.1103/physrevlett.109.037203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Indexed: 06/01/2023]
Abstract
Quenched disorder affects how nonequilibrium systems respond to driving. In the context of artificial spin ice, an athermal system comprised of geometrically frustrated classical Ising spins with a twofold degenerate ground state, we give experimental and numerical evidence of how such disorder washes out edge effects and provide an estimate of disorder strength in the experimental system. We prove analytically that a sequence of applied fields with fixed amplitude is unable to drive the system to its ground state from a saturated state. These results should be relevant for other systems where disorder does not change the nature of the ground state.
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Affiliation(s)
- Zoe Budrikis
- School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
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Metaxas PJ, Stamps RL, Jamet JP, Ferré J, Baltz V, Rodmacq B. Expansion and relaxation of magnetic mirror domains in a Pt/Co/Pt/Co/Pt multilayer with antiferromagnetic interlayer coupling. J Phys Condens Matter 2012; 24:024212. [PMID: 22173339 DOI: 10.1088/0953-8984/24/2/024212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We detail measurements of field-driven expansion and zero-field relaxation of magnetic mirror domains in antiferromagnetically coupled perpendicularly magnetized ultrathin Co layers. The zero-field stability of aligned ('mirror') domains in such systems results from non-homogeneous dipolar stray fields which exist in the vicinity of the domain walls. During field-driven domain expansion, we evidence a separation of the domain walls which form the mirror domain boundary. However, the walls realign, thereby reforming a mirror domain, if their final separation is below a critical distance at the end of the field pulse. This critical distance marks the point at which the effective net interaction between the walls changes from attractive to repulsive.
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Affiliation(s)
- P J Metaxas
- School of Physics, M013, University of Western Australia, Crawley, WA 6009, Australia.
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Budrikis Z, Politi P, Stamps RL. Diversity enabling equilibration: disorder and the ground state in artificial spin ice. Phys Rev Lett 2011; 107:217204. [PMID: 22181919 DOI: 10.1103/physrevlett.107.217204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Indexed: 05/31/2023]
Abstract
We report a novel approach to the question of whether and how the ground state can be achieved in square artificial spin ices where frustration is incomplete. We identify two sources of randomness that affect the approach to ground state: quenched disorder in the island response to fields and randomness in the sequence of driving fields. Numerical simulations show that quenched disorder can lead to final states with lower energy, and randomness in the sequence of driving fields always lowers the final energy attained by the system. We use a network picture to understand these two effects: disorder in island responses creates new dynamical pathways, and a random sequence of driving fields allows more pathways to be followed.
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Affiliation(s)
- Zoe Budrikis
- School of Physics, The University of Western Australia, Australia.
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Saerbeck T, Loh N, Lott D, Toperverg BP, Mulders AM, Fraile Rodríguez A, Freeland JW, Ali M, Hickey BJ, Stampfl APJ, Klose F, Stamps RL. Spatial fluctuations of loose spin coupling in CuMn/Co multilayers. Phys Rev Lett 2011; 107:127201. [PMID: 22026792 DOI: 10.1103/physrevlett.107.127201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Indexed: 05/31/2023]
Abstract
A detailed investigation of magnetic impurity-mediated interlayer exchange coupling observed in Cu(0.94)Mn(0.06)/Co multilayers using polarized neutron reflectometry and magnetic x-ray techniques is reported. Excellent descriptions of temperature and magnetic field dependent biquadratic coupling are obtained using a variant of the loose spin model that takes into account the distribution of the impurity Mn ions in three dimensions. Positional disorder of the magnetic impurities is shown to enhance biquadratic coupling via a new contribution J(2)(fluct), leading to a temperature dependent canting of magnetic domains in the multilayer. These results provide measurable effects on RKKY coupling associated with the distribution of impurities within planes parallel to the interfaces.
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Affiliation(s)
- T Saerbeck
- School of Physics, University of Western Australia, Crawley, WA6009, Australia.
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Gunawan V, Stamps RL. Surface and bulk polaritons in a PML-type magnetoelectric multiferroic with canted spins: TE and TM polarization. J Phys Condens Matter 2011; 23:105901. [PMID: 21335637 DOI: 10.1088/0953-8984/23/10/105901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present a theory for surface polaritons on ferroelectric-antiferromagnetic materials with canted spin structure. A small uniform canted moment is allowed, resulting in a weak ferromagnetism directed in the plane parallel to the surface. Surface and bulk polariton modes for a semi-infinite film are calculated for the case of transverse electric (TE) and transverse magnetic (TM) polarization. Example results are presented using parameters appropriate for BaMnF(4). We find that the surface modes are non-reciprocal for the TE polarization due to the magnetoelectric interaction, and the non-reciprocity can be controlled by an applied electric field. Example results for attenuated total reflection (ATR) are calculated. The magnetoelectric interaction also gives rise to 'leaky' surface modes in the case of TM polarization. These are pseudo-surface waves that exist in the pass band, and dissipate energy into the bulk of the material. We show that these pseudo-surface mode frequencies and properties can be modified by temperature and the application of external electric or magnetic fields.
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Affiliation(s)
- V Gunawan
- School of Physics M013, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
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Abstract
Local magnetic ordering in artificial spin ices is discussed from the point of view of how geometrical frustration controls dynamics and the approach to steady state. We discuss the possibility of using a particle picture based on vertex configurations to interpret the time evolution of magnetic configurations. Analysis of possible vertex processes allows us to anticipate different behaviors for open and closed edges and the existence of different field regimes. Numerical simulations confirm these results and also demonstrate the importance of correlations and long-range interactions in understanding particle population evolution. We also show that a mean-field model of vertex dynamics gives important insights into finite size effects.
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Affiliation(s)
- Zoe Budrikis
- School of Physics M013, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
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Metaxas PJ, Stamps RL, Jamet JP, Ferré J, Baltz V, Rodmacq B, Politi P. Dynamic binding of driven interfaces in coupled ultrathin ferromagnetic layers. Phys Rev Lett 2010; 104:237206. [PMID: 20867268 DOI: 10.1103/physrevlett.104.237206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Indexed: 05/29/2023]
Abstract
We demonstrate experimentally dynamic interface binding in a system consisting of two coupled ferromagnetic layers. While domain walls in each layer have different velocity-field responses, for two broad ranges of the driving field H, walls in the two layers are bound and move at a common velocity. The bound states have their own velocity-field response and arise when the isolated wall velocities in each layer are close, a condition which always occurs as H→0. Several features of the bound states are reproduced using a one-dimensional model, illustrating their general nature.
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Affiliation(s)
- P J Metaxas
- School of Physics, M013, University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
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Abstract
Magnetic relaxation experiments have been used to investigate the non-equilibrium dynamics of FePt nanoparticles. The system exhibits ageing at low temperatures, as well as a narrow energy distribution of the barrier to reversal. These properties were found susceptible to being affected by particle size, matrix and applied field strength. An analysis based on broad rate distributions is presented and compared with results obtained using energy barrier and viscosity interpretations. We find that a single broad distribution of relaxation times suggestive of cooperative effects is sufficient to explain the experimental results.
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Affiliation(s)
- R O Fuller
- Chemistry, M313, School of Chemical and Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley WA, 6009, Australia. School of Physics, M013, University of Western Australia, 35 Stirling Highway, Crawley WA, 6009, Australia
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Tripathy D, Adeyeye AO, Singh N, Stamps RL. Controlling the magnetization reversal in exchange-biased Co/CoO elongated nanorings. Nanotechnology 2009; 20:015304. [PMID: 19417249 DOI: 10.1088/0957-4484/20/1/015304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the control of magnetization reversal in exchange-biased Co/CoO nanorings resulting from the competition between field-cooling-induced unidirectional anisotropy at the Co/CoO interface and shape anisotropy of the elongated Co nanorings. We observed that the magnetization reversal mechanisms and magnitudes of exchange bias fields are strongly dependent on the strength and orientation of the cooling field relative to the major axis of the nanorings. Our results demonstrate a convenient technique to control the magnetization reversal modes in ferromagnetic nanorings.
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Affiliation(s)
- D Tripathy
- Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
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Metaxas PJ, Jamet JP, Mougin A, Cormier M, Ferré J, Baltz V, Rodmacq B, Dieny B, Stamps RL. Creep and flow regimes of magnetic domain-wall motion in ultrathin Pt/Co/Pt films with perpendicular anisotropy. Phys Rev Lett 2007; 99:217208. [PMID: 18233251 DOI: 10.1103/physrevlett.99.217208] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Indexed: 05/25/2023]
Abstract
We report on magnetic domain-wall velocity measurements in ultrathin Pt/Co(0.5-0.8 nm)/Pt films with perpendicular anisotropy over a large range of applied magnetic fields. The complete velocity-field characteristics are obtained, enabling an examination of the transition between thermally activated creep and viscous flow: motion regimes predicted from general theories for driven elastic interfaces in weakly disordered media. The dissipation limited flow regime is found to be consistent with precessional domain-wall motion, analysis of which yields values for the damping parameter, alpha.
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Affiliation(s)
- P J Metaxas
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France.
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Bauer M, Mougin A, Jamet JP, Repain V, Ferré J, Stamps RL, Bernas H, Chappert C. Deroughening of domain wall pairs by dipolar repulsion. Phys Rev Lett 2005; 94:207211. [PMID: 16090287 DOI: 10.1103/physrevlett.94.207211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Indexed: 05/03/2023]
Abstract
As a magnetic domain wall propagates under small fields through a random potential, it roughens as a result of weak collective pinning, known as creep. Using Kerr microscopy, we report experimental evidence of a surprising deroughening of wall pairs in the creep regime, in a 0.5 nm thick Co layer with perpendicular anisotropy. A bound state is found in cases where two rough domains nucleated far away from one another and first growing under the action of a magnetic field eventually do not merge. The two domains remain separated by a strip of unreversed magnetization, characterized by flat edges and stabilized by dipolar fields. A creep theory that includes dipolar interactions between domains successfully accounts for (i) the domain wall deroughening as the width of the strip decreases and (ii) the quasistatic and dynamic field dependence of the strip width s.
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Affiliation(s)
- M Bauer
- Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris Sud, 91405 Orsay, France
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Abstract
Maxwell’s equations applied to low-dimensional magnetic structures
result in a number of interesting features. For example, the magnetic fields
generated by two-dimensional arrays of Heisenberg spins can stabilise long
range magnetic order and determine critical temperatures. Aspects of this
problem are discussed, and considerations for the dynamic response of weakly
coupled arrays of fine magnetic particles are presented. Finally, a form of
effective medium theory designed to overcome difficulties in treating
magnetostatic interactions in magnetic nanostructures is described.
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Stamps RL, Camley RE. Spin waves in antiferromagnetic thin films and multilayers: Surface and interface exchange and entire-cell effective-medium theory. Phys Rev B Condens Matter 1996; 54:15200-15209. [PMID: 9985582 DOI: 10.1103/physrevb.54.15200] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Liu X, Stamps RL, Sooryakumar R, Prinz GA. Spin-wave hybridization and magnetic anisotropies in a thick bcc cobalt film. Phys Rev B Condens Matter 1996; 54:11903-11906. [PMID: 9985026 DOI: 10.1103/physrevb.54.11903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Camley RE, Hicken RJ. Influence of exchange-coupled anisotropies on spin-wave frequencies in magnetic layered systems: Application to Co/CoO. Phys Rev B Condens Matter 1996; 54:4159-4164. [PMID: 9986319 DOI: 10.1103/physrevb.54.4159] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Subramanian S, Liu X, Stamps RL, Sooryakumar R, Prinz GA. Magnetic anisotropies in body-centered-cubic cobalt films. Phys Rev B Condens Matter 1995; 52:10194-10201. [PMID: 9980070 DOI: 10.1103/physrevb.52.10194] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Carriço AS, Camley RE, Stamps RL. Phase diagram of thin antiferromagnetic films in strong magnetic fields. Phys Rev B Condens Matter 1994; 50:13453-13460. [PMID: 9975539 DOI: 10.1103/physrevb.50.13453] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Camley RE, Nörtemann FC, Tilley DR. Dynamic susceptibilities for magnetic layered structures. Phys Rev B Condens Matter 1993; 48:15740-15743. [PMID: 10008126 DOI: 10.1103/physrevb.48.15740] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Nörtemann FC, Stamps RL, Camley RE. Microscopic calculation of spin waves in antiferromagnetically coupled multilayers: Nonreciprocity and finite-size effects. Phys Rev B Condens Matter 1993; 47:11910-11923. [PMID: 10005363 DOI: 10.1103/physrevb.47.11910] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Stamps RL, Camley RE, Hillebrands B, Güntherodt G. Spin-wave propagation on imperfect ultrathin ferromagnetic films. Phys Rev B Condens Matter 1993; 47:5072-5076. [PMID: 10006671 DOI: 10.1103/physrevb.47.5072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Nörtemann FC, Stamps RL, Camley RE, Hillebrands B, Güntherodt G. Effective-medium theory for finite magnetic multilayers: Effect of anisotropy on dipolar modes. Phys Rev B Condens Matter 1993; 47:3225-3230. [PMID: 10006407 DOI: 10.1103/physrevb.47.3225] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Krams P, Lauks F, Stamps RL, Hillebrands B, Güntherodt G. Magnetic anisotropies of ultrathin Co(001) films on Cu(001). Phys Rev Lett 1992; 69:3674-3677. [PMID: 10046884 DOI: 10.1103/physrevlett.69.3674] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Nörtemann FC, Stamps RL, Carriço AS, Camley RE. Finite-size effects on spin configurations in antiferromagnetically coupled multilayers. Phys Rev B Condens Matter 1992; 46:10847-10853. [PMID: 10002946 DOI: 10.1103/physrevb.46.10847] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Camley RE, Hillebrands B, Güntherodt G. Reflection of spin waves by atomic steps. Phys Rev B Condens Matter 1992; 46:10836-10840. [PMID: 10002944 DOI: 10.1103/physrevb.46.10836] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Fassbender J, Nörtemann F, Stamps RL, Camley RE, Hillebrands B, Güntherodt G, Parkin SS. Oscillatory interlayer exchange coupling of Co/Ru multilayers investigated by Brillouin light scattering. Phys Rev B Condens Matter 1992; 46:5810-5813. [PMID: 10004387 DOI: 10.1103/physrevb.46.5810] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Hillebrands B. Dipolar interactions and the magnetic behavior of two-dimensional ferromagnetic systems. Phys Rev B Condens Matter 1991; 44:12417-12423. [PMID: 9999398 DOI: 10.1103/physrevb.44.12417] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Hillebrands B. Dipole-exchange modes in multilayers with out-of-plane anisotropies. Phys Rev B Condens Matter 1991; 44:5095-5104. [PMID: 9998318 DOI: 10.1103/physrevb.44.5095] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Hillebrands B. Dipole-exchange modes in thin ferromagnetic films with strong out-of-plane anisotropies. Phys Rev B Condens Matter 1991; 43:3532-3539. [PMID: 9997668 DOI: 10.1103/physrevb.43.3532] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Johnson BL, Camley RE. Nonreciprocal reflection from semi-infinite antiferromagnets. Phys Rev B Condens Matter 1991; 43:3626-3636. [PMID: 9997679 DOI: 10.1103/physrevb.43.3626] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Camley RE. Green's functions for antiferromagnetic polaritons. II. Scattering from rough surfaces. Phys Rev B Condens Matter 1989; 40:609-621. [PMID: 9990951 DOI: 10.1103/physrevb.40.609] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Camley RE. Green's functions for antiferromagnetic polaritons. I. Surface modes and resonances. Phys Rev B Condens Matter 1989; 40:596-608. [PMID: 9990950 DOI: 10.1103/physrevb.40.596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stamps RL, Camley RE. Dipole-exchange spin-wave modes in very-thin-film antiferromagnets. Phys Rev B Condens Matter 1987; 35:1919-1931. [PMID: 9941618 DOI: 10.1103/physrevb.35.1919] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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