1
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Yue WC, Yuan Z, Huang P, Sun Y, Gao T, Lyu YY, Tu X, Dong S, He L, Dong Y, Cao X, Kang L, Wang H, Wu P, Nisoli C, Wang YL. Toroidic phase transitions in a direct-kagome artificial spin ice. NATURE NANOTECHNOLOGY 2024; 19:1101-1107. [PMID: 38684808 DOI: 10.1038/s41565-024-01666-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/27/2024] [Indexed: 05/02/2024]
Abstract
Ferrotoroidicity-the fourth form of primary ferroic order-breaks both space and time-inversion symmetry. So far, direct observation of ferrotoroidicity in natural materials remains elusive, which impedes the exploration of ferrotoroidic phase transitions. Here we overcome the limitations of natural materials using an artificial nanomagnet system that can be characterized at the constituent level and at different effective temperatures. We design a nanomagnet array as to realize a direct-kagome spin ice. This artificial spin ice exhibits robust toroidal moments and a quasi-degenerate ground state with two distinct low-temperature toroidal phases: ferrotoroidicity and paratoroidicity. Using magnetic force microscopy and Monte Carlo simulation, we demonstrate a phase transition between ferrotoroidicity and paratoroidicity, along with a cross-over to a non-toroidal paramagnetic phase. Our quasi-degenerate artificial spin ice in a direct-kagome structure provides a model system for the investigation of magnetic states and phase transitions that are inaccessible in natural materials.
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Affiliation(s)
- Wen-Cheng Yue
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Zixiong Yuan
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Peiyuan Huang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Yizhe Sun
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China
| | - Tan Gao
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Yang-Yang Lyu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Xuecou Tu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Sining Dong
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China.
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China.
| | - Liang He
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China
| | - Ying Dong
- College of Metrology Measurement and Instrument, China Jiliang University, Hangzhou, China
| | - Xun Cao
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Lin Kang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Huabing Wang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
- Purple Mountain Laboratories, Nanjing, China.
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China.
| | - Peiheng Wu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Cristiano Nisoli
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Yong-Lei Wang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
- Purple Mountain Laboratories, Nanjing, China.
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China.
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China.
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2
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Büker B, Ramermann D, Piel PM, Bünte J, Ennen I, Hütten A. Simulated Guidance in Interpreting Nano-Patterned Co 70Fe 30 Film Imaging with Differential Phase Contrast. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:116. [PMID: 38202571 PMCID: PMC10780791 DOI: 10.3390/nano14010116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/29/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024]
Abstract
Our paper introduces a simulation-based framework designed to interpret differential phase contrast (DPC) magnetic imaging within the transmission electron microscope (TEM). We investigate patterned magnetic membranes, particularly focusing on nano-patterned Co70Fe30 thin-film membranes fabricated via focused ion beam (FIB) milling. Our direct magnetic imaging reveals regular magnetic domain patterns in these carefully prepared systems. Notably, the observed magnetic structure aligns precisely with micromagnetic simulations based on the dimensions of the underlying nanostructures. This agreement emphasizes the usefulness of micromagnetic simulations, not only for the interpretation of DPC data, but also for the prediction of possible microstructures in magnetic sensor systems with nano-patterns.
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Affiliation(s)
| | | | | | | | | | - Andreas Hütten
- Faculty of Physics, Bielefeld University, Universitaetsstraße 25, 33615 Bielefeld, Germany; (B.B.); (D.R.); (P.-M.P.); (J.B.); (I.E.)
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3
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Bhat VS, Watanabe S, Kronast F, Baumgaertl K, Grundler D. Spin dynamics, loop formation and cooperative reversal in artificial quasicrystals with tailored exchange coupling. COMMUNICATIONS PHYSICS 2023; 6:193. [PMID: 38665397 PMCID: PMC11041715 DOI: 10.1038/s42005-023-01310-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 07/19/2023] [Indexed: 04/28/2024]
Abstract
Aperiodicity and un-conventional rotational symmetries allow quasicrystalline structures to exhibit unusual physical and functional properties. In magnetism, artificial ferromagnetic quasicrystals exhibited knee anomalies suggesting reprogrammable magnetic properties via non-stochastic switching. However, the decisive roles of short-range exchange and long-range dipolar interactions have not yet been clarified for optimized reconfigurable functionality. We report broadband spin-wave spectroscopy and X-ray photoemission electron microscopy on different quasicrystal lattices consisting of ferromagnetic Ni81Fe19 nanobars arranged on aperiodic Penrose and Ammann tilings with different exchange and dipolar interactions. We imaged the magnetic states of partially reversed quasicrystals and analyzed their configurations in terms of the charge model, geometrical frustration and the formation of flux-closure loops. Only the exchange-coupled lattices are found to show aperiodicity-specific collective phenomena and non-stochastic switching. Both, exchange and dipolarly coupled quasicrystals show magnonic excitations with narrow linewidths in minor loop measurements. Thereby reconfigurable functionalities in spintronics and magnonics become realistic.
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Affiliation(s)
- Vinayak Shantaram Bhat
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, 02668 Warsaw, Poland
| | - Sho Watanabe
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Florian Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Korbinian Baumgaertl
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Dirk Grundler
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Electrical and Micro Engineering (IEM), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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4
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Hu W, Zhang Z, Liao Y, Li Q, Shi Y, Zhang H, Zhang X, Niu C, Wu Y, Yu W, Zhou X, Guo H, Wang W, Xiao J, Yin L, Liu Q, Shen J. Distinguishing artificial spin ice states using magnetoresistance effect for neuromorphic computing. Nat Commun 2023; 14:2562. [PMID: 37142614 PMCID: PMC10160026 DOI: 10.1038/s41467-023-38286-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 04/24/2023] [Indexed: 05/06/2023] Open
Abstract
Artificial spin ice (ASI) consisting patterned array of nano-magnets with frustrated dipolar interactions offers an excellent platform to study frustrated physics using direct imaging methods. Moreover, ASI often hosts a large number of nearly degenerated and non-volatile spin states that can be used for multi-bit data storage and neuromorphic computing. The realization of the device potential of ASI, however, critically relies on the capability of transport characterization of ASI, which has not been demonstrated so far. Using a tri-axial ASI system as the model system, we demonstrate that transport measurements can be used to distinguish the different spin states of the ASI system. Specifically, by fabricating a tri-layer structure consisting a permalloy base layer, a Cu spacer layer and the tri-axial ASI layer, we clearly resolve different spin states in the tri-axial ASI system using lateral transport measurements. We have further demonstrated that the tri-axial ASI system has all necessary required properties for reservoir computing, including rich spin configurations to store input signals, nonlinear response to input signals, and fading memory effect. The successful transport characterization of ASI opens up the prospect for novel device applications of ASI in multi-bit data storage and neuromorphic computing.
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Affiliation(s)
- Wenjie Hu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Zefeng Zhang
- Frontier Institute of Chip and System, Fudan University, Shanghai, China
- Research Institute of Intelligent Complex Systems and ISTBI, Fudan University, Shanghai, China
| | - Yanghui Liao
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Qiang Li
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Yang Shi
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Huanyu Zhang
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Xumeng Zhang
- Frontier Institute of Chip and System, Fudan University, Shanghai, China
| | - Chang Niu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Yu Wu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Weichao Yu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Xiaodong Zhou
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Hangwen Guo
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Wenbin Wang
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Jiang Xiao
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
- Shanghai Research Center for Quantum Sciences, Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China
| | - Lifeng Yin
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China.
- Shanghai Qi Zhi Institute, Shanghai, China.
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
- Shanghai Research Center for Quantum Sciences, Shanghai, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China.
- State Key Laboratory of Integrated Chips and Systems, Fudan University, Shanghai, China.
| | - Qi Liu
- Frontier Institute of Chip and System, Fudan University, Shanghai, China.
- State Key Laboratory of Integrated Chips and Systems, Fudan University, Shanghai, China.
| | - Jian Shen
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China.
- Shanghai Qi Zhi Institute, Shanghai, China.
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
- Shanghai Research Center for Quantum Sciences, Shanghai, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China.
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, Shanghai, China.
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5
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Bhattacharya D, Chen Z, Jensen CJ, Liu C, Burks EC, Gilbert DA, Zhang X, Yin G, Liu K. 3D Interconnected Magnetic Nanowire Networks as Potential Integrated Multistate Memristors. NANO LETTERS 2022; 22:10010-10017. [PMID: 36480011 DOI: 10.1021/acs.nanolett.2c03616] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Interconnected magnetic nanowire (NW) networks offer a promising platform for three-dimensional (3D) information storage and integrated neuromorphic computing. Here we report discrete propagation of magnetic states in interconnected Co nanowire networks driven by magnetic field and current, manifested in distinct magnetoresistance (MR) features. In these networks, when only a few interconnected NWs were measured, multiple MR kinks and local minima were observed, including a significant minimum at a positive field during the descending field sweep. Micromagnetic simulations showed that this unusual feature was due to domain wall (DW) pinning at the NW intersections, which was confirmed by off-axis electron holography imaging. In a complex network with many intersections, sequential switching of nanowire sections separated by interconnects was observed, along with stochastic characteristics. The pinning/depinning of the DWs can be further controlled by the driving current density. These results illustrate the promise of such interconnected networks as integrated multistate memristors.
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Affiliation(s)
| | - Zhijie Chen
- Physics Department, Georgetown University, Washington, D.C.20057, United States
| | | | - Chen Liu
- Physical Science and Engineering Division, King Abdullah University of Science & Technology, Thuwal23955-6900, Saudi Arabia
| | - Edward C Burks
- Physics Department, University of California, Davis, California95618, United States
| | - Dustin A Gilbert
- Department of Materials Science and Engineering, and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science & Technology, Thuwal23955-6900, Saudi Arabia
| | - Gen Yin
- Physics Department, Georgetown University, Washington, D.C.20057, United States
| | - Kai Liu
- Physics Department, Georgetown University, Washington, D.C.20057, United States
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6
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Yue WC, Yuan Z, Lyu YY, Dong S, Zhou J, Xiao ZL, He L, Tu X, Dong Y, Wang H, Xu W, Kang L, Wu P, Nisoli C, Kwok WK, Wang YL. Crystallizing Kagome Artificial Spin Ice. PHYSICAL REVIEW LETTERS 2022; 129:057202. [PMID: 35960577 DOI: 10.1103/physrevlett.129.057202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/16/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Artificial spin ices are engineered arrays of dipolarly coupled nanobar magnets. They enable direct investigations of fascinating collective phenomena from their diverse microstates. However, experimental access to ground states in the geometrically frustrated systems has proven difficult, limiting studies and applications of novel properties and functionalities from the low energy states. Here, we introduce a convenient approach to control the competing diploar interactions between the neighboring nanomagnets, allowing us to tailor the vertex degeneracy of the ground states. We achieve this by tuning the length of selected nanobar magnets in the spin ice lattice. We demonstrate the effectiveness of our method by realizing multiple low energy microstates in a kagome artificial spin ice, particularly the hardly accessible long range ordered ground state-the spin crystal state. Our strategy can be directly applied to other artificial spin systems to achieve exotic phases and explore new emergent collective behaviors.
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Affiliation(s)
- Wen-Cheng Yue
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Zixiong Yuan
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Yang-Yang Lyu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
| | - Sining Dong
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
| | - Jian Zhou
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Zhi-Li Xiao
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics, Northern Illinois University, DeKalb, Illinois 60115, USA
| | - Liang He
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Xuecou Tu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Purple Mountain Laboratories, Nanjing 211111, China
| | - Ying Dong
- Research Center for Quantum Sensing, Zhejiang Lab, Hangzhou, Zhejiang 311121, China
| | - Huabing Wang
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Purple Mountain Laboratories, Nanjing 211111, China
| | - Weiwei Xu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
| | - Lin Kang
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Purple Mountain Laboratories, Nanjing 211111, China
| | - Peiheng Wu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Purple Mountain Laboratories, Nanjing 211111, China
| | - Cristiano Nisoli
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Wai-Kwong Kwok
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yong-Lei Wang
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
- Purple Mountain Laboratories, Nanjing 211111, China
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7
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Realization of macroscopic ratchet effect based on nonperiodic and uneven potentials. Sci Rep 2021; 11:16617. [PMID: 34400750 PMCID: PMC8368205 DOI: 10.1038/s41598-021-96192-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/04/2021] [Indexed: 11/28/2022] Open
Abstract
Ratchet devices allow turning an ac input signal into a dc output signal. A ratchet device is set by moving particles driven by zero averages forces on asymmetric potentials. Hybrid nanostructures combining artificially fabricated spin ice nanomagnet arrays with superconducting films have been identified as a good choice to develop ratchet nanodevices. In the current device, the asymmetric potentials are provided by charged Néel walls located in the vertices of spin ice magnetic honeycomb array, whereas the role of moving particles is played by superconducting vortices. We have experimentally obtained ratchet effect for different spin ice I configurations and for vortex lattice moving parallel or perpendicular to magnetic easy axes. Remarkably, the ratchet magnitudes are similar in all the experimental runs; i. e. different spin ice I configurations and in both relevant directions of the vortex lattice motion. We have simulated the interplay between vortex motion directions and a single asymmetric potential. It turns out vortices interact with uneven asymmetric potentials, since they move with trajectories crossing charged Néel walls with different orientations. Moreover, we have found out the asymmetric pair potentials which generate the local ratchet effect. In this rocking ratchet the particles (vortices) on the move are interacting each other (vortex lattice); therefore, the ratchet local effect turns into a global macroscopic effect. In summary, this ratchet device benefits from interacting particles moving in robust and topological protected type I spin ice landscapes.
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8
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Caravelli F, Saccone M, Nisoli C. On the degeneracy of spin ice graphs, and its estimate via the Bethe permanent. Proc Math Phys Eng Sci 2021. [DOI: 10.1098/rspa.2021.0108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The concept of spin ice can be extended to a general graph. We study the degeneracy of spin ice graph on arbitrary interaction structures via graph theory. We map spin ice graphs to the Ising model on a graph and clarify whether the inverse mapping is possible via a modified Krausz construction. From the gauge freedom of frustrated Ising systems, we derive exact, general results about frustration and degeneracy. We demonstrate for the first time that every spin ice graph, with the exception of the one-dimensional Ising model, is degenerate. We then study how degeneracy scales in size, using the mapping between Eulerian trails and spin ice manifolds, and a permanental identity for the number of Eulerian orientations. We show that the Bethe permanent technique provides both an estimate and a lower bound to the frustration of spin ices on arbitrary graphs of even degree. While such a technique can also be used to obtain an upper bound, we find that in all finite degree examples we studied, another upper bound based on Schrijver inequality is tighter.
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Affiliation(s)
- Francesco Caravelli
- Theoretical Division (T4), Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Michael Saccone
- Theoretical Division (T4), Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Cristiano Nisoli
- Theoretical Division (T4), Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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9
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Chaurasiya AK, Mondal AK, Gartside JC, Stenning KD, Vanstone A, Barman S, Branford WR, Barman A. Comparison of Spin-Wave Modes in Connected and Disconnected Artificial Spin Ice Nanostructures Using Brillouin Light Scattering Spectroscopy. ACS NANO 2021; 15:11734-11742. [PMID: 34132521 DOI: 10.1021/acsnano.1c02537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Artificial spin ice systems have seen burgeoning interest due to their intriguing physics and potential applications in reprogrammable memory, logic, and magnonics. Integration of artificial spin ice with functional magnonics is a relatively recent research direction, with a host of promising results. As the field progresses, direct in-depth comparisons of distinct artificial spin systems are crucial to advancing the field. While studies have investigated the effects of different lattice geometries, little comparison exists between systems comprising continuously connected nanostructures, where spin-waves propagate via dipole-exchange interaction, and systems with nanobars disconnected at vertices, where spin-wave propagation occurs via stray dipolar field. Gaining understanding of how these very different coupling methods affect both spin-wave dynamics and magnetic reversal is key for the field to progress and provides crucial system-design information including for future systems containing combinations of connected and disconnected elements. Here, we study the magnonic response of two kagome spin ices via Brillouin light scattering, a continuously connected system and a disconnected system with vertex gaps. We observe distinct high-frequency dynamics and magnetization reversal regimes between the systems, with key distinctions in spin-wave localization and mode quantization, microstate trajectory during reversal and internal field profiles. These observations are pertinent for the fundamental understanding of artificial spin systems and broader design and engineering of reconfigurable functional magnonic crystals.
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Affiliation(s)
- Avinash Kumar Chaurasiya
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block - JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Amrit Kumar Mondal
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block - JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Jack C Gartside
- Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kilian D Stenning
- Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, United Kingdom
| | - Alex Vanstone
- Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, United Kingdom
| | - Saswati Barman
- Institute of Engineering and Management, Sector-V, Salt Lake, Kolkata 700 091, India
| | - Will R Branford
- Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, United Kingdom
- London Centre for Nanotechnology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Anjan Barman
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block - JD, Sector-III, Salt Lake, Kolkata 700 106, India
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10
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May A, Saccone M, van den Berg A, Askey J, Hunt M, Ladak S. Magnetic charge propagation upon a 3D artificial spin-ice. Nat Commun 2021; 12:3217. [PMID: 34050163 PMCID: PMC8163774 DOI: 10.1038/s41467-021-23480-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 04/30/2021] [Indexed: 11/09/2022] Open
Abstract
Magnetic charge propagation in spin-ice materials has yielded a paradigm-shift in science, allowing the symmetry between electricity and magnetism to be studied. Recent work is now suggesting the spin-ice surface may be important in mediating the ordering and associated phase space in such materials. Here, we detail a 3D artificial spin-ice, which captures the exact geometry of bulk systems, allowing magnetic charge dynamics to be directly visualized upon the surface. Using magnetic force microscopy, we observe vastly different magnetic charge dynamics along two principal directions. For a field applied along the surface termination, local energetics force magnetic charges to nucleate over a larger characteristic distance, reducing their magnetic Coulomb interaction and producing uncorrelated monopoles. In contrast, applying a field transverse to the surface termination yields highly correlated monopole-antimonopole pairs. Detailed simulations suggest it is the difference in effective chemical potential as well as the energy landscape experienced during dynamics that yields the striking differences in monopole transport.
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Affiliation(s)
- A May
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - M Saccone
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM, USA.,Theoretical Division (T4), Los Alamos National Laboratory, Los Alamos, NM, USA
| | - A van den Berg
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - J Askey
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - M Hunt
- School of Physics and Astronomy, Cardiff University, Cardiff, UK
| | - S Ladak
- School of Physics and Astronomy, Cardiff University, Cardiff, UK.
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11
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Rodríguez-Gallo C, Ortiz-Ambriz A, Tierno P. Topological Boundary Constraints in Artificial Colloidal Ice. PHYSICAL REVIEW LETTERS 2021; 126:188001. [PMID: 34018772 DOI: 10.1103/physrevlett.126.188001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/17/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The effect of boundaries and how these can be used to influence the bulk behavior in geometrically frustrated systems are both long-standing puzzles, often relegated to a secondary role. Here, we use numerical simulations and "proof of concept" experiments to demonstrate that boundaries can be engineered to control the bulk behavior in a colloidal artificial ice. We show that an antiferromagnetic frontier forces the system to rapidly reach the ground state (GS), as opposed to the commonly implemented open or periodic boundary conditions. We also show that strategically placing defects at the corners generates novel bistable states, or topological strings, which result from competing GS regions in the bulk. Our results could be generalized to other frustrated micro- and nanostructures where boundary conditions may be engineered with lithographic techniques.
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Affiliation(s)
- Carolina Rodríguez-Gallo
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, 08028, Barcelona, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Antonio Ortiz-Ambriz
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, 08028, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Pietro Tierno
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, 08028, Barcelona, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, 08028, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
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12
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Lendinez S, Kaffash MT, Jungfleisch MB. Emergent Spin Dynamics Enabled by Lattice Interactions in a Bicomponent Artificial Spin Ice. NANO LETTERS 2021; 21:1921-1927. [PMID: 33600721 DOI: 10.1021/acs.nanolett.0c03729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Artificial spin ice (ASI) networks are arrays of nanoscaled magnets that can serve both as models for frustration in atomic spin ice as well as for exploring new spin-wave-based strategies to transmit, process, and store information. Here, we exploit the intricate interplay of the magnetization dynamics of two dissimilar ferromagnetic metals arranged on complementary lattice sites in a square ASI to modulate the spin-wave properties effectively. We show that the interaction between the two sublattices results in unique spectra attributed to each sublattice, and we observe inter- and intralattice dynamics facilitated by the distinct magnetization properties of the two materials. The dynamic properties are systematically studied by angular-dependent broadband ferromagnetic resonance and confirmed by micromagnetic simulations. We show that combining materials with dissimilar magnetic properties enables the realization of a wide range of two-dimensional structures, potentially opening the door to new concepts in nanomagnonics.
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Affiliation(s)
- Sergi Lendinez
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States
| | - Mojtaba T Kaffash
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States
| | - M Benjamin Jungfleisch
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States
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13
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Yumnam G, Chen Y, Guo J, Keum J, Lauter V, Singh DK. Quantum Disordered State of Magnetic Charges in Nanoengineered Honeycomb Lattice. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2004103. [PMID: 33747751 PMCID: PMC7967061 DOI: 10.1002/advs.202004103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Indexed: 06/12/2023]
Abstract
A quantum magnetic state due to magnetic charges is never observed, even though they are treated as quantum mechanical variables in theoretical calculations. Here, the occurrence of a novel quantum disordered state of magnetic charges in a nanoengineered magnetic honeycomb lattice of ultra-small connecting elements is demonstrated. The experimental research, performed using spin resolved neutron scattering, reveals a massively degenerate ground state, comprised of low integer and energetically forbidden high integer magnetic charges, that manifests cooperative paramagnetism at low temperature. The system tends to preserve the degenerate configuration even under large magnetic field application. It exemplifies the robustness of disordered correlation of magnetic charges in a 2D honeycomb lattice. The realization of quantum disordered ground state elucidates the dominance of exchange energy, which is enabled due to the nanoscopic magnetic element size in nanoengineered honeycomb. Consequently, an archetypal platform is envisaged to study quantum mechanical phenomena due to emergent magnetic charges.
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Affiliation(s)
- George Yumnam
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
| | - Yiyao Chen
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
| | - Jiasen Guo
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
| | - Jong Keum
- Oak Ridge National LaboratoryOak RidgeTN37831USA
| | | | - Deepak Kumar Singh
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
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14
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Bang W, Silvani R, Hoffmann A, Ketterson JB, Montoncello F, Jungfleisch MB. Ferromagnetic resonance in single vertices and 2D lattices macro-dipoles of elongated nanoelements: measurements and simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:065803. [PMID: 33091893 DOI: 10.1088/1361-648x/abc402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report broadband ferromagnetic resonance measurements of the in-plane magnetic field response of three- and four-fold symmetric vertices formed by non-contacting permalloy nano-ellipses together with extended lattices constructed from them. Complementing the experimental data with simulations, we are able to show that, as far as the most intense FMR responses are concerned, the spectra of vertices and lattices can largely be interpreted in terms of a superposition of the underlying hysteretic responses of the individual ellipses, as elemental building blocks of the system. This property suggest that it is possible to understand the orientation of the individual magnetic dipole moments in a dipole network in terms of dynamic measurements alone, thereby offering a powerful tool to analyze the alignment statistics in frustrated systems that are exposed to various magnetic histories.
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Affiliation(s)
- Wonbae Bang
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, United States of America
- Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, United States of America
| | - R Silvani
- Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, I-06123, Italy
- Istituto Nazionale di Ricerca Metrologica, Torino, I-10135, Italy
| | - A Hoffmann
- Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, United States of America
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - J B Ketterson
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, United States of America
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL 60208, United States of America
| | - F Montoncello
- Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Ferrara, I-44121, Italy
| | - M B Jungfleisch
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States of America
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15
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Llandro J, Love DM, Kovács A, Caron J, Vyas KN, Kákay A, Salikhov R, Lenz K, Fassbender J, Scherer MRJ, Cimorra C, Steiner U, Barnes CHW, Dunin-Borkowski RE, Fukami S, Ohno H. Visualizing Magnetic Structure in 3D Nanoscale Ni-Fe Gyroid Networks. NANO LETTERS 2020; 20:3642-3650. [PMID: 32250635 DOI: 10.1021/acs.nanolett.0c00578] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Arrays of interacting 2D nanomagnets display unprecedented electromagnetic properties via collective effects, demonstrated in artificial spin ices and magnonic crystals. Progress toward 3D magnetic metamaterials is hampered by two challenges: fabricating 3D structures near intrinsic magnetic length scales (sub-100 nm) and visualizing their magnetic configurations. Here, we fabricate and measure nanoscale magnetic gyroids, periodic chiral networks comprising nanowire-like struts forming three-connected vertices. Via block copolymer templating, we produce Ni75Fe25 single-gyroid and double-gyroid (an inversion pair of single-gyroids) nanostructures with a 42 nm unit cell and 11 nm diameter struts, comparable to the exchange length in Ni-Fe. We visualize their magnetization distributions via off-axis electron holography with nanometer spatial resolution and interpret the patterns using finite-element micromagnetic simulations. Our results suggest an intricate, frustrated remanent state which is ferromagnetic but without a unique equilibrium configuration, opening new possibilities for collective phenomena in magnetism, including 3D magnonic crystals and unconventional computing.
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Affiliation(s)
- Justin Llandro
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - David M Love
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Jan Caron
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Kunal N Vyas
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Attila Kákay
- Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Ruslan Salikhov
- Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Kilian Lenz
- Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Jürgen Fassbender
- Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Bautzner Landstrasse 400, 01328 Dresden, Germany
- Technische Universität Dresden, Haeckelstrasse 3, 01069 Dresden, Germany
| | - Maik R J Scherer
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Christian Cimorra
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Ullrich Steiner
- Adolphe Merkle Institute, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Crispin H W Barnes
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Shunsuke Fukami
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, 468-1 Aramaki Aza Aoba, Aoba-ku, Sendai 980-0845 Japan
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Hideo Ohno
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, 468-1 Aramaki Aza Aoba, Aoba-ku, Sendai 980-0845 Japan
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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16
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Askey J, Hunt MO, Langbein W, Ladak S. Use of Two-Photon Lithography with a Negative Resist and Processing to Realise Cylindrical Magnetic Nanowires. NANOMATERIALS 2020; 10:nano10030429. [PMID: 32121262 PMCID: PMC7152837 DOI: 10.3390/nano10030429] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/13/2020] [Accepted: 02/22/2020] [Indexed: 12/29/2022]
Abstract
Cylindrical magnetic nanowires have been shown to exhibit a vast array of fascinating spin textures, including chiral domains, skyrmion tubes, and topologically protected domain walls that harbor Bloch points. Here, we present a novel methodology that utilizes two-photon lithography in order to realize tailored three-dimensional (3D) porous templates upon prefabricated electrodes. Electrochemical deposition is used to fill these porous templates, and reactive ion etching is used to free the encased magnetic nanowires. The nanowires are found to have a diameter of 420 nm, length of 2.82 μm, and surface roughness of 7.6 nm. Magnetic force microscopy in an externally applied field suggests a complex spiraling magnetization state, which demagnetizes via the production of vortices of alternating chirality. Detailed micro-magnetic simulations confirm such a state and a qualitative agreement is found with respect to the switching of experimental nanowires. Surprisingly, simulations also indicate the presence of a Bloch point as a metastable state during the switching process. Our work provides a new means to realize 3D magnetic nanowires of controlled geometry and calculations suggest a further reduction in diameter to sub-200 nm will be possible, providing access to a regime of ultrafast domain wall motion.
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Affiliation(s)
| | | | | | - Sam Ladak
- Correspondence: ; Tel.: +44-(0)292-087-0157
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17
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Lendinez S, Jungfleisch MB. Magnetization dynamics in artificial spin ice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:013001. [PMID: 31600143 DOI: 10.1088/1361-648x/ab3e78] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this topical review, we present key results of studies on magnetization dynamics in artificial spin ice (ASI), which are arrays of magnetically interacting nanostructures. Recent experimental and theoretical progress in this emerging area, which is at the boundary between research on frustrated magnetism and high-frequency studies of artificially created nanomagnets, is reviewed. The exploration of ASI structures has revealed fascinating discoveries in correlated spin systems. Artificially created spin ice lattices offer unique advantages as they allow for a control of the interactions between the elements by their geometric properties and arrangement. Magnonics, on the other hand, is a field that explores spin dynamics in the gigahertz frequency range in magnetic micro- and nanostructures. In this context, magnonic crystals are particularly important as they allow the modification of spin-wave properties and the observation of band gaps in the resonance spectra. Very recently, there has been considerable progress, experimentally and theoretically, in combining aspects of both fields-artificial spin ice and magnonics-enabling new functionalities in magnonic and spintronic applications using ASI, as well as providing a deeper understanding of geometrical frustration in the gigahertz range. Different approaches for the realization of ASI structures and their experimental characterization in the high-frequency range are described and the appropriate theoretical models and simulations are reviewed. Special attention is devoted to linking these findings to the quasi-static behavior of ASI and dynamic investigations in magnonics in an effort to bridge the gap between both areas further and to stimulate new research endeavors.
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Affiliation(s)
- S Lendinez
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States of America
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18
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Chen Y, Summers B, Dahal A, Lauter V, Vignale G, Singh DK. Field and Current Control of the Electrical Conductivity of an Artificial 2D Honeycomb Lattice. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1808298. [PMID: 30811683 DOI: 10.1002/adma.201808298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Indexed: 06/09/2023]
Abstract
The conductivity of a neodymium-based artificial honeycomb lattice undergoes dramatic changes upon application of magnetic fields and currents. These changes are attributed to a redistribution of magnetic charges that are formed at the vertices of the honeycomb due to the nonvanishing net flux of magnetization from adjacent magnetic elements. It is suggested that the application of a large magnetic field or a current causes a transition from a disordered state, in which magnetic charges are distributed at random, to an ordered state, in which they are regularly arranged on the sites of two interpenetrating triangular Wigner crystals. The field and current tuning of electrical properties are highly desirable functionalities for spintronics applications. Consequently, a new spintronics research platform can be envisaged using artificial magnetic honeycomb lattices.
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Affiliation(s)
- Yiyao Chen
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Brock Summers
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Ashutosh Dahal
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Valeria Lauter
- Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Giovanni Vignale
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Deepak K Singh
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
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19
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Li Y, Paterson GW, Macauley GM, Nascimento FS, Ferguson C, Morley SA, Rosamond MC, Linfield EH, MacLaren DA, Macêdo R, Marrows CH, McVitie S, Stamps RL. Superferromagnetism and Domain-Wall Topologies in Artificial "Pinwheel" Spin Ice. ACS NANO 2019; 13:2213-2222. [PMID: 30588800 DOI: 10.1021/acsnano.8b08884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
For over ten years, arrays of interacting single-domain nanomagnets, referred to as artificial spin ices, have been engineered with the aim to study frustration in model spin systems. Here, we use Fresnel imaging to study the reversal process in "pinwheel" artificial spin ice, a modified square ASI structure obtained by rotating each island by some angle about its midpoint. Our results demonstrate that a simple 45° rotation changes the magnetic ordering from antiferromagnetic to ferromagnetic, creating a superferromagnet which exhibits mesoscopic domain growth mediated by domain wall nucleation and coherent domain propagation. We observe several domain-wall configurations, most of which are direct analogues to those seen in continuous ferromagnetic films. However, charged walls also appear due to the geometric constraints of the system. Changing the orientation of the external magnetic field allows control of the nature of the spin reversal with the emergence of either one- or two-dimensional avalanches. This property of pinwheel ASI could be employed to tune devices based on magnetotransport phenomena such as Hall circuits.
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Affiliation(s)
- Yue Li
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Gary W Paterson
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Gavin M Macauley
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Fabio S Nascimento
- Departamento de Física , Universidade Federal de Viçosa , Viçosa 36570-900 , Minas Gerais , Brazil
| | - Ciaran Ferguson
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Sophie A Morley
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
- Department of Physics , University of California , Santa Cruz , California 95064 , United States
| | - Mark C Rosamond
- School of Electronic and Electrical Engineering , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Edmund H Linfield
- School of Electronic and Electrical Engineering , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Donald A MacLaren
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Rair Macêdo
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Christopher H Marrows
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Stephen McVitie
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Robert L Stamps
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
- Department of Physics and Astronomy , University of Manitoba , Manitoba R3T 2N2 , Canada
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20
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Nisoli C. Unexpected Phenomenology in Particle-Based Ice Absent in Magnetic Spin Ice. PHYSICAL REVIEW LETTERS 2018; 120:167205. [PMID: 29756919 DOI: 10.1103/physrevlett.120.167205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Indexed: 06/08/2023]
Abstract
While particle-based ices are often considered essentially equivalent to magnet-based spin ices, the two differ essentially in frustration and energetics. We show that at equilibrium particle-based ices correspond exactly to spin ices coupled to a background field. In trivial geometries, such a field has no effect, and the two systems are indeed thermodynamically equivalent. In other cases, however, the field controls a richer phenomenology, absent in magnetic ices, and still largely unexplored: ice rule fragility, topological charge transfer, radial polarization, decimation induced disorder, and glassiness.
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Affiliation(s)
- Cristiano Nisoli
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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21
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Glavic A, Summers B, Dahal A, Kline J, Van Herck W, Sukhov A, Ernst A, Singh DK. Spin Solid versus Magnetic Charge Ordered State in Artificial Honeycomb Lattice of Connected Elements. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1700856. [PMID: 29721429 PMCID: PMC5908362 DOI: 10.1002/advs.201700856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Indexed: 06/08/2023]
Abstract
The nature of magnetic correlation at low temperature in two-dimensional artificial magnetic honeycomb lattice is a strongly debated issue. While theoretical researches suggest that the system will develop a novel zero entropy spin solid state as T → 0 K, a confirmation to this effect in artificial honeycomb lattice of connected elements is lacking. This study reports on the investigation of magnetic correlation in newly designed artificial permalloy honeycomb lattice of ultrasmall elements, with a typical length of ≈12 nm, using neutron scattering measurements and temperature-dependent micromagnetic simulations. Numerical modeling of the polarized neutron reflectometry data elucidates the temperature-dependent evolution of spin correlation in this system. As temperature reduces to ≈7 K, the system tends to develop novel spin solid state, manifested by the alternating distribution of magnetic vortex loops of opposite chiralities. Experimental results are complemented by temperature-dependent micromagnetic simulations that confirm the dominance of spin solid state over local magnetic charge ordered state in the artificial honeycomb lattice with connected elements. These results enable a direct investigation of novel spin solid correlation in the connected honeycomb geometry of 2D artificial structure.
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Affiliation(s)
- Artur Glavic
- Laboratory for Neutron Scattering and ImagingPaul Scherrer Institut5232Villigen PSISwitzerland
| | - Brock Summers
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
| | - Ashutosh Dahal
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
| | - Joseph Kline
- National Institute of Standards and TechnologyGaithersburgMD20899USA
| | - Walter Van Herck
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier‐Leibnitz Zentrum (MLZ)Forschungszentrum Jülich GmbHLichtenbergstr. 185748GarchingGermany
| | - Alexander Sukhov
- Forschungszentrum Jülich GmbHHelmholtz Institute Erlangen‐Nürnberg for Renewable Energy (IEK‐11)90429NürnbergGermany
| | - Arthur Ernst
- Institut für Theoretische PhysikJohannes Kepler UniversitätA 4040LinzAustria
- Max‐Planck‐Institut für MikrostrukturphysikWeinberg 206120HalleGermany
| | - Deepak K. Singh
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211USA
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22
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Gartside JC, Arroo DM, Burn DM, Bemmer VL, Moskalenko A, Cohen LF, Branford WR. Realization of ground state in artificial kagome spin ice via topological defect-driven magnetic writing. NATURE NANOTECHNOLOGY 2018; 13:53-58. [PMID: 29158603 DOI: 10.1038/s41565-017-0002-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 09/14/2017] [Indexed: 06/07/2023]
Abstract
Arrays of non-interacting nanomagnets are widespread in data storage and processing. As current technologies approach fundamental limits on size and thermal stability, enhancing functionality through embracing the strong interactions present at high array densities becomes attractive. In this respect, artificial spin ices are geometrically frustrated magnetic metamaterials that offer vast untapped potential due to their unique microstate landscapes, with intriguing prospects in applications from reconfigurable logic to magnonic devices or hardware neural networks. However, progress in such systems is impeded by the inability to access more than a fraction of the total microstate space. Here, we demonstrate that topological defect-driven magnetic writing-a scanning probe technique-provides access to all of the possible microstates in artificial spin ices and related arrays of nanomagnets. We create previously elusive configurations such as the spin-crystal ground state of artificial kagome dipolar spin ices and high-energy, low-entropy 'monopole-chain' states that exhibit negative effective temperatures.
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Affiliation(s)
- Jack C Gartside
- Blackett Laboratory, Imperial College London, London, SW7 2AZ, UK.
| | - Daan M Arroo
- Blackett Laboratory, Imperial College London, London, SW7 2AZ, UK
| | | | - Victoria L Bemmer
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
| | - Andy Moskalenko
- Blackett Laboratory, Imperial College London, London, SW7 2AZ, UK
| | - Lesley F Cohen
- Blackett Laboratory, Imperial College London, London, SW7 2AZ, UK
| | - Will R Branford
- Blackett Laboratory, Imperial College London, London, SW7 2AZ, UK
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23
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Summers B, Chen Y, Dahal A, Singh DK. New Description of Evolution of Magnetic Phases in Artificial Honeycomb Lattice. Sci Rep 2017; 7:16080. [PMID: 29167461 PMCID: PMC5700068 DOI: 10.1038/s41598-017-15786-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/01/2017] [Indexed: 11/08/2022] Open
Abstract
Artificial magnetic honeycomb lattice provides a two-dimensional archetypal system to explore novel phenomena of geometrically frustrated magnets. According to theoretical reports, an artificial magnetic honeycomb lattice is expected to exhibit several phase transitions to unique magnetic states as a function of reducing temperature. Experimental investigations of permalloy artificial honeycomb lattice of connected ultra-small elements, [Formula: see text] 12 nm, reveal a more complicated behavior. First, upon cooling the sample to intermediate temperature, [Formula: see text] 175 K, the system manifests a non-unique state where the long range order co-exists with short-range magnetic charge order and weak spin ice state. Second, at much lower temperature, [Formula: see text] 6 K, the long-range spin solid state exhibits a re-entrant behavior. Both observations are in direct contrast to the present understanding of this system. New theoretical approaches are needed to develop a comprehensive formulation of this two dimensional magnet.
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Affiliation(s)
- B Summers
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - Y Chen
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - A Dahal
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - D K Singh
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
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24
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Gliga S, Hrkac G, Donnelly C, Büchi J, Kleibert A, Cui J, Farhan A, Kirk E, Chopdekar RV, Masaki Y, Bingham NS, Scholl A, Stamps RL, Heyderman LJ. Emergent dynamic chirality in a thermally driven artificial spin ratchet. NATURE MATERIALS 2017; 16:1106-1111. [PMID: 29058727 DOI: 10.1038/nmat5007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/12/2017] [Indexed: 05/22/2023]
Abstract
Modern nanofabrication techniques have opened the possibility to create novel functional materials, whose properties transcend those of their constituent elements. In particular, tuning the magnetostatic interactions in geometrically frustrated arrangements of nanoelements called artificial spin ice can lead to specific collective behaviour, including emergent magnetic monopoles, charge screening and transport, as well as magnonic response. Here, we demonstrate a spin-ice-based active material in which energy is converted into unidirectional dynamics. Using X-ray photoemission electron microscopy we show that the collective rotation of the average magnetization proceeds in a unique sense during thermal relaxation. Our simulations demonstrate that this emergent chiral behaviour is driven by the topology of the magnetostatic field at the edges of the nanomagnet array, resulting in an asymmetric energy landscape. In addition, a bias field can be used to modify the sense of rotation of the average magnetization. This opens the possibility of implementing a magnetic Brownian ratchet, which may find applications in novel nanoscale devices, such as magnetic nanomotors, actuators, sensors or memory cells.
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Affiliation(s)
- Sebastian Gliga
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Gino Hrkac
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
| | - Claire Donnelly
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Jonathan Büchi
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Jizhai Cui
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Alan Farhan
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Advanced Light Source, Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, California 94720, USA
| | - Eugenie Kirk
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Rajesh V Chopdekar
- Department of Materials Science and Engineering, University of California, Davis, Davis, California 95616, USA
| | - Yusuke Masaki
- Department of Physics, University of Tokyo, Tokyo 113-0033, Japan
| | - Nicholas S Bingham
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- National Research Council Research Associate at the US Naval Research Laboratory, 4555 Overlook Avenue, SW Washington DC 20375, USA
| | - Andreas Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, California 94720, USA
| | - Robert L Stamps
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Laura J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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25
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Bramwell ST. Artificial spin ice: A ratchet made of tiny magnets. NATURE MATERIALS 2017; 16:1053-1054. [PMID: 29058726 DOI: 10.1038/nmat5004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- Steven T Bramwell
- Department of Physics and Astronomy and at the London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AJ, UK
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26
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Wiedwald U, Gräfe J, Lebecki KM, Skripnik M, Haering F, Schütz G, Ziemann P, Goering E, Nowak U. Magnetic switching of nanoscale antidot lattices. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:733-50. [PMID: 27335762 PMCID: PMC4901900 DOI: 10.3762/bjnano.7.65] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/30/2016] [Indexed: 06/06/2023]
Abstract
We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.
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Affiliation(s)
- Ulf Wiedwald
- Institute of Solid State Physics, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany
| | - Joachim Gräfe
- Max-Planck-Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Kristof M Lebecki
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- IT4Innovations Centre, VSB Technical University of Ostrava, Czech Republic
| | - Maxim Skripnik
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Felix Haering
- Institute of Solid State Physics, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Gisela Schütz
- Max-Planck-Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Paul Ziemann
- Institute of Solid State Physics, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Eberhard Goering
- Max-Planck-Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Ulrich Nowak
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
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27
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Wang YL, Xiao ZL, Snezhko A, Xu J, Ocola LE, Divan R, Pearson JE, Crabtree GW, Kwok WK. Rewritable artificial magnetic charge ice. Science 2016; 352:962-6. [DOI: 10.1126/science.aad8037] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 04/13/2016] [Indexed: 11/02/2022]
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28
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Farmer B, Bhat VS, Balk A, Teipel E, Smith N, Unguris J, Keavney DJ, Hastings JT, De Long LE. Direct imaging of coexisting ordered and frustrated sublattices in artificial ferromagnetic quasicrystals. PHYSICAL REVIEW. B 2016; 93:134428. [PMID: 28691109 PMCID: PMC5497597 DOI: 10.1103/physrevb.93.134428] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have used scanning electron microscopy with polarization analysis and photoemission electron microscopy to image the two-dimensional magnetization of permalloy films patterned into Penrose P2 tilings (P2T). The interplay of exchange interactions in asymmetrically coordinated vertices and short-range dipole interactions among connected film segments stabilize magnetically ordered, spatially distinct sublattices that coexist with frustrated sublattices at room temperature. Numerical simulations that include long-range dipole interactions between sublattices agree with images of as-grown P2T samples and predict a magnetically ordered ground state for a two-dimensional quasicrystal lattice of classical Ising spins.
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Affiliation(s)
- B Farmer
- Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, Kentucky 40506-0055, USA
| | - V S Bhat
- Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, Kentucky 40506-0055, USA
| | - A Balk
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, USA
- Maryland Nanocenter, University of Maryland, College Park, Maryland 20742, USA
| | - E Teipel
- Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, Kentucky 40506-0055, USA
| | - N Smith
- Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, Kentucky 40506-0055, USA
| | - J Unguris
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, USA
| | - D J Keavney
- Advanced Photon Source 431-E007, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439, USA
| | - J T Hastings
- Department of Electrical and Computer Engineering, University of Kentucky, 453F Paul Anderson Tower, Lexington, Kentucky 40506-0046, USA
| | - L E De Long
- Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, Kentucky 40506-0055, USA
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29
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Engineering of frustration in colloidal artificial ices realized on microfeatured grooved lattices. Nat Commun 2016; 7:10575. [PMID: 26830629 PMCID: PMC4740443 DOI: 10.1038/ncomms10575] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/30/2015] [Indexed: 11/09/2022] Open
Abstract
Artificial spin ice systems, namely lattices of interacting single domain ferromagnetic islands, have been used to date as microscopic models of frustration induced by lattice topology, allowing for the direct visualization of spin arrangements and textures. However, the engineering of frustrated ice states in which individual spins can be manipulated in situ and the real-time observation of their collective dynamics remain both challenging tasks. Inspired by recent theoretical advances, here we realize a colloidal version of an artificial spin ice system using interacting polarizable particles confined to lattices of bistable gravitational traps. We show quantitatively that ice-selection rules emerge in this frustrated soft matter system by tuning the strength of the pair interactions between the microscopic units. Via independent control of particle positioning and dipolar coupling, we introduce monopole-like defects and strings and use loops with defined chirality as an elementary unit to store binary information. Visualizing the dynamics of electron spins in frustrated systems is a challenging task, which may require an alternative way at the microscale. Here, the authors realize an artificial system composed of interacting colloidal particles to mimick frustrated spins, which is potentially helpful in information storage.
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30
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Krawczyk M, Grundler D. Review and prospects of magnonic crystals and devices with reprogrammable band structure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:123202. [PMID: 24599025 DOI: 10.1088/0953-8984/26/12/123202] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Research efforts addressing spin waves (magnons) in microand nanostructured ferromagnetic materials have increased tremendously in recent years. Corresponding experimental and theoretical work in magnonics faces significant challenges in that spinwave dispersion relations are highly anisotropic and different magnetic states might be realized via, for example, the magnetic field history. At the same time, these features offer novel opportunities for wave control in solids going beyond photonics and plasmonics. In this topical review we address materials with a periodic modulation of magnetic parameters that give rise to artificially tailored band structures and allow unprecedented control of spin waves. In particular, we discuss recent achievements and perspectives of reconfigurable magnonic devices for which band structures can be reprogrammed during operation. Such characteristics might be useful for multifunctional microwave and logic devices operating over a broad frequency regime on either the macroor nanoscale.
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31
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Kang SH, Shan S, Košmrlj A, Noorduin WL, Shian S, Weaver JC, Clarke DR, Bertoldi K. Complex ordered patterns in mechanical instability induced geometrically frustrated triangular cellular structures. PHYSICAL REVIEW LETTERS 2014; 112:098701. [PMID: 24655285 DOI: 10.1103/physrevlett.112.098701] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Indexed: 06/03/2023]
Abstract
Geometrical frustration arises when a local order cannot propagate throughout the space because of geometrical constraints. This phenomenon plays a major role in many systems leading to disordered ground-state configurations. Here, we report a theoretical and experimental study on the behavior of buckling-induced geometrically frustrated triangular cellular structures. To our surprise, we find that buckling induces complex ordered patterns which can be tuned by controlling the porosity of the structures. Our analysis reveals that the connected geometry of the cellular structure plays a crucial role in the generation of ordered states in this frustrated system.
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Affiliation(s)
- Sung Hoon Kang
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Sicong Shan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Andrej Košmrlj
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Wim L Noorduin
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Samuel Shian
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - James C Weaver
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, USA
| | - David R Clarke
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Katia Bertoldi
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA and Kavli Institute, Harvard University, Cambridge, Massachusetts 02138, USA
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32
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Crystallites of magnetic charges in artificial spin ice. Nature 2013; 500:553-7. [DOI: 10.1038/nature12399] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 06/14/2013] [Indexed: 11/09/2022]
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33
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Bhat VS, Sklenar J, Farmer B, Woods J, Hastings JT, Lee SJ, Ketterson JB, De Long LE. Controlled magnetic reversal in Permalloy films patterned into artificial quasicrystals. PHYSICAL REVIEW LETTERS 2013; 111:077201. [PMID: 23992078 DOI: 10.1103/physrevlett.111.077201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 07/12/2013] [Indexed: 06/02/2023]
Abstract
We have patterned novel Permalloy thin films with quasicrystalline Penrose P2 tilings and measured their dc magnetization and ferromagnetic resonance absorption. Reproducible anomalies in the hysteretic, low-field data signal a series of abrupt transitions between ordered magnetization textures, culminating in a smooth evolution into a saturated state. Micromagnetic simulations compare well to experimental dc hysteresis loops and ferromagnetic resonance spectra and indicate that systematic control of magnetic reversal and domain wall motion can be achieved via tiling design, offering a new paradigm of magnonic quasicrystals.
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Affiliation(s)
- V S Bhat
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
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34
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Latimer ML, Berdiyorov GR, Xiao ZL, Peeters FM, Kwok WK. Realization of artificial ice systems for magnetic vortices in a superconducting MoGe thin film with patterned nanostructures. PHYSICAL REVIEW LETTERS 2013; 111:067001. [PMID: 23971602 DOI: 10.1103/physrevlett.111.067001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Indexed: 06/02/2023]
Abstract
We report an anomalous matching effect in MoGe thin films containing pairs of circular holes arranged in such a way that four of those pairs meet at each vertex point of a square lattice. A remarkably pronounced fractional matching was observed in the magnetic field dependences of both the resistance and the critical current. At the half matching field the critical current can be even higher than that at zero field. This has never been observed before for vortices in superconductors with pinning arrays. Numerical simulations within the nonlinear Ginzburg-Landau theory reveal a square vortex ice configuration in the ground state at the half matching field and demonstrate similar characteristic features in the field dependence of the critical current, confirming the experimental realization of an artificial ice system for vortices for the first time.
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Affiliation(s)
- M L Latimer
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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35
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The non-random walk of chiral magnetic charge carriers in artificial spin ice. Sci Rep 2013; 3:1252. [PMID: 23409243 PMCID: PMC3570775 DOI: 10.1038/srep01252] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/14/2013] [Indexed: 12/02/2022] Open
Abstract
The flow of magnetic charge carriers (dubbed magnetic monopoles) through frustrated spin ice lattices, governed simply by Coulombic forces, represents a new direction in electromagnetism. Artificial spin ice nanoarrays realise this effect at room temperature, where the magnetic charge is carried by domain walls. Control of domain wall path is one important element of utilizing this new medium. By imaging the transit of domain walls across different connected 2D honeycomb structures we contribute an important aspect which will enable that control to be realized. Although apparently equivalent paths are presented to a domain wall as it approaches a Y-shaped vertex from a bar parallel to the field, we observe a stark non-random path distribution, which we attribute to the chirality of the magnetic charges. These observations are supported by detailed statistical modelling and micromagnetic simulations. The identification of chiral control to magnetic charge path selectivity invites analogy with spintronics.
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36
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Yakubovich OV, Yakovleva EV, Golovanov AN, Volkov AS, Volkova OS, Zvereva EA, Dimitrova OV, Vasiliev AN. The First Vanadate–Carbonate, K2Mn3(VO4)2(CO3): Crystal Structure and Physical Properties. Inorg Chem 2013; 52:1538-43. [DOI: 10.1021/ic302333e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Olga S. Volkova
- M. V. Lomonosov Moscow State University, Moscow 119991, Russia
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