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Gaur SS, Marinero EE. Emergent Magnonic Materials: Challenges and Opportunities. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6299. [PMID: 37763576 PMCID: PMC10533023 DOI: 10.3390/ma16186299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/11/2023] [Accepted: 09/16/2023] [Indexed: 09/29/2023]
Abstract
Advances in information technology are hindered by energy dissipation from Joule losses associated with charge transport. In contrast, the process of information based on spin waves propagation (magnons) in magnetic materials is dissipationless. Low damping of spin wave excitations is essential to control the propagation length of magnons. Ferrimagnetic Y3Fe5O12 garnets (YIG) exhibit the lowest magnetic damping constants. However, to attain the lowest damping constant, epitaxial growth of YIG on single crystal substrates of Gd3Ga5O12 at elevated temperatures is required, which hinders their CMOS integration in electronic devices. Furthermore, their low saturation magnetization and magnetocrystalline anisotropy are challenging for nanoscale device applications. In the search for alternative material systems, polycrystalline ferromagnetic Co25Fe75 alloy films and ferrimagnetic spinel ferrites, such as MgAl0.5Fe1.5O4 (MAFO), have emerged as potential candidates. Their damping constants are comparable, although they are at least one order of magnitude higher than YIG's. However, Co25Fe75 alloy thin film growth is CMOS compatible, and its magnon diffusion length is 20× longer than in MAFO. In addition, MAFO requires epitaxial growth on lattice-matched MgAl2O4 substrates. We discuss the material properties that control the Gilbert damping constant in CoxFe1-x alloys and MAFO and conclude that CoxFe1-x alloy thin films bring us closer to the realization of the exploitation of spin waves for magnonics.
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Affiliation(s)
| | - Ernesto E. Marinero
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
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Zheng XY, Channa S, Riddiford LJ, Wisser JJ, Mahalingam K, Bowers CT, McConney ME, N'Diaye AT, Vailionis A, Cogulu E, Ren H, Galazka Z, Kent AD, Suzuki Y. Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping. Nat Commun 2023; 14:4918. [PMID: 37582804 PMCID: PMC10427713 DOI: 10.1038/s41467-023-40733-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
Ultra-thin films of low damping ferromagnetic insulators with perpendicular magnetic anisotropy have been identified as critical to advancing spin-based electronics by significantly reducing the threshold for current-induced magnetization switching while enabling new types of hybrid structures or devices. Here, we have developed a new class of ultra-thin spinel structure Li0.5Al1.0Fe1.5O4 (LAFO) films on MgGa2O4 (MGO) substrates with: 1) perpendicular magnetic anisotropy; 2) low magnetic damping and 3) the absence of degraded or magnetic dead layers. These films have been integrated with epitaxial Pt spin source layers to demonstrate record low magnetization switching currents and high spin-orbit torque efficiencies. These LAFO films on MGO thus combine all of the desirable properties of ferromagnetic insulators with perpendicular magnetic anisotropy, opening new possibilities for spin based electronics.
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Affiliation(s)
- Xin Yu Zheng
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.
| | - Sanyum Channa
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Lauren J Riddiford
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
| | - Jacob J Wisser
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | | | - Cynthia T Bowers
- Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA
| | - Michael E McConney
- Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Arturas Vailionis
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA, 94305, USA
- Department of Physics, Kaunas University of Technology, Studentu Street 50, LT-51368, Kaunas, Lithuania
| | - Egecan Cogulu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Haowen Ren
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Zbigniew Galazka
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany
| | - Andrew D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Yuri Suzuki
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
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Dubnack O, Müller FA. Oxidic 2D Materials. MATERIALS 2021; 14:ma14185213. [PMID: 34576436 PMCID: PMC8469416 DOI: 10.3390/ma14185213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 11/18/2022]
Abstract
The possibility of producing stable thin films, only a few atomic layers thick, from a variety of materials beyond graphene has led to two-dimensional (2D) materials being studied intensively in recent years. By reducing the layer thickness and approaching the crystallographic monolayer limit, a variety of unexpected and technologically relevant property phenomena were observed, which also depend on the subsequent arrangement and possible combination of individual layers to form heterostructures. These properties can be specifically used for the development of multifunctional devices, meeting the requirements of the advancing miniaturization of modern manufacturing technologies and the associated need to stabilize physical states even below critical layer thicknesses of conventional materials in the fields of electronics, magnetism and energy conversion. Differences in the structure of potential two-dimensional materials result in decisive influences on possible growth methods and possibilities for subsequent transfer of the thin films. In this review, we focus on recent advances in the rapidly growing field of two-dimensional materials, highlighting those with oxidic crystal structure like perovskites, garnets and spinels. In addition to a selection of well-established growth techniques and approaches for thin film transfer, we evaluate in detail their application potential as free-standing monolayers, bilayers and multilayers in a wide range of advanced technological applications. Finally, we provide suggestions for future developments of this promising research field in consideration of current challenges regarding scalability and structural stability of ultra-thin films.
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Affiliation(s)
- Oliver Dubnack
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany;
| | - Frank A. Müller
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany;
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743 Jena, Germany
- Correspondence:
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Alotibi S, Hickey BJ, Teobaldi G, Ali M, Barker J, Poli E, O'Regan DD, Ramasse Q, Burnell G, Patchett J, Ciccarelli C, Alyami M, Moorsom T, Cespedes O. Enhanced Spin-Orbit Coupling in Heavy Metals via Molecular Coupling. ACS APPLIED MATERIALS & INTERFACES 2021; 13:5228-5234. [PMID: 33470108 DOI: 10.1021/acsami.0c19403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
5d metals are used in electronics because of their high spin-orbit coupling (SOC) leading to efficient spin-electric conversion. When C60 is grown on a metal, the electronic structure is altered due to hybridization and charge transfer. In this work, we measure the spin Hall magnetoresistance for Pt/C60 and Ta/C60, finding that they are up to a factor of 6 higher than those for pristine metals, indicating a 20-60% increase in the spin Hall angle. At low fields of 1-30 mT, the presence of C60 increased the anisotropic magnetoresistance by up to 700%. Our measurements are supported by noncollinear density functional theory calculations, which predict a significant SOC enhancement by C60 that penetrates through the Pt layer, concomitant with trends in the magnetic moment of transport electrons acquired via SOC and symmetry breaking. The charge transfer and hybridization between the metal and C60 can be controlled by gating, so our results indicate the possibility of dynamically modifying the SOC of thin metals using molecular layers. This could be exploited in spin-transfer torque memories and pure spin current circuits.
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Affiliation(s)
- Satam Alotibi
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Bryan J Hickey
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Gilberto Teobaldi
- Scientific Computing Department, Science and Technology Facilities Council, Didcot OX11 0QX, U.K
- Beijing Computational Science Research Center, Beijing 100193, China
- Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Liverpool L69 3BX, U.K
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Mannan Ali
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Joseph Barker
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Emiliano Poli
- Scientific Computing Department, Science and Technology Facilities Council, Didcot OX11 0QX, U.K
| | - David D O'Regan
- School of Physics, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and the SFI Advanced Materials and Bio-Engineering Research Centre (AMBER), Dublin 2, Ireland
| | - Quentin Ramasse
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
- SuperSTEM, SciTech Daresbury Science and Innovation Campus, Keckwick Lane, Daresbury WA4 4AD, U.K
| | - Gavin Burnell
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - James Patchett
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Chiara Ciccarelli
- SuperSTEM, SciTech Daresbury Science and Innovation Campus, Keckwick Lane, Daresbury WA4 4AD, U.K
| | - Mohammed Alyami
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Timothy Moorsom
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
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Caretta L, Oh SH, Fakhrul T, Lee DK, Lee BH, Kim SK, Ross CA, Lee KJ, Beach GSD. Relativistic kinematics of a magnetic soliton. Science 2020; 370:1438-1442. [PMID: 33335059 DOI: 10.1126/science.aba5555] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/19/2020] [Accepted: 11/13/2020] [Indexed: 11/02/2022]
Abstract
A tenet of special relativity is that no particle can exceed the speed of light. In certain magnetic materials, the maximum magnon group velocity serves as an analogous relativistic limit for the speed of magnetic solitons. Here, we drive domain walls to this limit in a low-dissipation magnetic insulator using pure spin currents from the spin Hall effect. We achieve record current-driven velocities in excess of 4300 meters per second-within ~10% of the relativistic limit-and we observe key signatures of relativistic motion associated with Lorentz contraction, which leads to velocity saturation. The experimental results are well explained through analytical and atomistic modeling. These observations provide critical insight into the fundamental limits of the dynamics of magnetic solitons and establish a readily accessible experimental framework to study relativistic solitonic physics.
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Affiliation(s)
- Lucas Caretta
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Se-Hyeok Oh
- Department of Nano-Semiconductor and Engineering, Korea University, Seoul 02841, Korea
| | - Takian Fakhrul
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Dong-Kyu Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
| | - Byung Hun Lee
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Se Kwon Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Caroline A Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Kyung-Jin Lee
- Department of Nano-Semiconductor and Engineering, Korea University, Seoul 02841, Korea.,Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea.,Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
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Interfacial Dzyaloshinskii-Moriya interaction arising from rare-earth orbital magnetism in insulating magnetic oxides. Nat Commun 2020; 11:1090. [PMID: 32107384 PMCID: PMC7046643 DOI: 10.1038/s41467-020-14924-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 02/12/2020] [Indexed: 11/09/2022] Open
Abstract
The Dzyaloshinskii-Moriya interaction (DMI) is responsible for exotic chiral and topological magnetic states such as spin spirals and skyrmions. DMI manifests at metallic ferromagnet/heavy-metal interfaces, owing to inversion symmetry breaking and spin-orbit coupling by a heavy metal such as Pt. Moreover, in centrosymmetric magnetic oxides interfaced by Pt, DMI-driven topological spin textures and fast current-driven dynamics have been reported, though the origin of this DMI is unclear. While in metallic systems, spin-orbit coupling arises from a proximate heavy metal, we show that in perpendicularly-magnetized iron garnets, rare-earth orbital magnetism gives rise to an intrinsic spin-orbit coupling generating interfacial DMI at mirror symmetry-breaking interfaces. We show that rare-earth ion substitution and strain engineering can significantly alter the DMI. These results provide critical insights into the origins of chiral magnetism in low-damping magnetic oxides and identify paths toward engineering chiral and topological states in centrosymmetric oxides through rare-earth ion substitution. The origin of interfacial Dzyaloshinskii-Moriya interaction (iDMI) in insulating magnetic oxides remains unclear. Here, Caretta et al. find that an intrinsic spin-orbit coupling due to rare-earth orbital magnetism generates iDMI at mirror symmetry-breaking interfaces of magnetized iron garnets Tm3Fe5O12.
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Emori S, Yi D, Crossley S, Wisser JJ, Balakrishnan PP, Khodadadi B, Shafer P, Klewe C, N'Diaye AT, Urwin BT, Mahalingam K, Howe BM, Hwang HY, Arenholz E, Suzuki Y. Ultralow Damping in Nanometer-Thick Epitaxial Spinel Ferrite Thin Films. NANO LETTERS 2018; 18:4273-4278. [PMID: 29792812 DOI: 10.1021/acs.nanolett.8b01261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Pure spin currents, unaccompanied by dissipative charge flow, are essential for realizing energy-efficient nanomagnetic information and communications devices. Thin-film magnetic insulators have been identified as promising materials for spin-current technology because they are thought to exhibit lower damping compared with their metallic counterparts. However, insulating behavior is not a sufficient requirement for low damping, as evidenced by the very limited options for low-damping insulators. Here, we demonstrate a new class of nanometer-thick ultralow-damping insulating thin films based on design criteria that minimize orbital angular momentum and structural disorder. Specifically, we show ultralow damping in <20 nm thick spinel-structure magnesium aluminum ferrite (MAFO), in which magnetization arises from Fe3+ ions with zero orbital angular momentum. These epitaxial MAFO thin films exhibit a Gilbert damping parameter of ∼0.0015 and negligible inhomogeneous linewidth broadening, resulting in narrow half width at half-maximum linewidths of ∼0.6 mT around 10 GHz. Our findings offer an attractive thin-film platform for enabling integrated insulating spintronics.
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Affiliation(s)
- Satoru Emori
- Department of Physics , Virginia Polytechnic Institute and State University , Blacksburg , Virginia 24060 , United States
| | | | | | | | | | - Behrouz Khodadadi
- Department of Physics , Virginia Polytechnic Institute and State University , Blacksburg , Virginia 24060 , United States
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Brittany T Urwin
- Materials and Manufacturing Directorate , Air Force Research Laboratory , Wright-Patterson Air Force Base , Ohio 45433 , United States
| | - Krishnamurthy Mahalingam
- Materials and Manufacturing Directorate , Air Force Research Laboratory , Wright-Patterson Air Force Base , Ohio 45433 , United States
| | - Brandon M Howe
- Materials and Manufacturing Directorate , Air Force Research Laboratory , Wright-Patterson Air Force Base , Ohio 45433 , United States
| | | | - Elke Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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