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Bran C, Fernandez-Roldan JA, Moreno JA, Fraile Rodríguez A, Del Real RP, Asenjo A, Saugar E, Marqués-Marchán J, Mohammed H, Foerster M, Aballe L, Kosel J, Vazquez M, Chubykalo-Fesenko O. Domain wall propagation and pinning induced by current pulses in cylindrical modulated nanowires. NANOSCALE 2023; 15:8387-8394. [PMID: 37092798 DOI: 10.1039/d3nr00455d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The future developments in 3D magnetic nanotechnology require the control of domain wall dynamics by means of current pulses. While this has been extensively studied in 2D magnetic strips (planar nanowires), few reports on this exist in cylindrical geometry, where Bloch point domain walls are expected to have intriguing properties. Here, we report an investigation on cylindrical magnetic Ni nanowires with geometrical notches. An experimental work based on synchrotron X-ray magnetic circular dichroism (XMCD) combined with photoemission electron microscopy (PEEM) indicates that large current densities induce domain wall nucleation, while smaller currents move domain walls preferably antiparallel to the current direction. In the region where no pinning centers are present, we found a domain wall velocity of about 1 km s-1. Thermal modelling indicates that large current densities temporarily raise the temperature in the nanowire above the Curie temperature, leading to nucleation of domain walls during the system cooling. Micromagnetic modelling with a spin-torque effect shows that for intermediate current densities, Bloch point domain walls with chirality parallel to the Oersted field propagate antiparallel to the current direction. In other cases, domain walls can be bounced from the notches and/or get pinned outside their positions. We thus found that current is not only responsible for domain wall propagation, but also is a source of pinning due to the Oersted field action.
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Affiliation(s)
- C Bran
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, 28049, Spain.
| | - J A Fernandez-Roldan
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - J A Moreno
- King Abdullah University of Science and Technology, Computer Electrical and Mathematical Science and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - A Fraile Rodríguez
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, 08028, Spain
- Institut de Nanociencia i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona, 08028, Spain
| | - R P Del Real
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, 28049, Spain.
| | - A Asenjo
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, 28049, Spain.
| | - E Saugar
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, 28049, Spain.
| | - J Marqués-Marchán
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, 28049, Spain.
| | - H Mohammed
- King Abdullah University of Science and Technology, Computer Electrical and Mathematical Science and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - M Foerster
- ALBA Synchrotron Light Facility, CELLS, Barcelona, 08290, Spain
| | - L Aballe
- ALBA Synchrotron Light Facility, CELLS, Barcelona, 08290, Spain
| | - J Kosel
- King Abdullah University of Science and Technology, Computer Electrical and Mathematical Science and Engineering, Thuwal 23955-6900, Saudi Arabia
- Silicon Austria Labs, Villach 9524, Austria
| | - M Vazquez
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, 28049, Spain.
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2
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Review of Helical Magnetic Structures in Magnetic Microwires. CHEMOSENSORS 2022. [DOI: 10.3390/chemosensors10080291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
We provide an overview of the helical magnetic structures in magnetic microwires. Having analyzed the experimental data describing the magnetic behavior of magnetic microwires since the 1990s, we found indirect evidence of the existence of various types of helical magnetic structures. Purposeful research has allowed us to discover the spiral magnetic structure as one of the most unusual helical structures. A comparison of the spiral structure with another type of helical structure—elliptical—was carried out. In the analysis, emphasis was placed on the length of the domain wall as one of the most important parameters. The difference in the dynamic properties of the spiral and elliptical domain walls has been demonstrated.
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Chen W, Zhang W, Liu Y, Meng FC, Dudley JM, Lu YQ. Time diffraction-free transverse orbital angular momentum beams. Nat Commun 2022; 13:4021. [PMID: 35821372 PMCID: PMC9276663 DOI: 10.1038/s41467-022-31623-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 06/24/2022] [Indexed: 11/28/2022] Open
Abstract
The discovery of optical transverse orbital angular momentum (OAM) has broadened our understanding of light and is expected to promote optics and other physics. However, some fundamental questions concerning the nature of such OAM remain, particularly whether they can survive from observed mode degradation and hold OAM values higher than 1. Here, we show that the strong degradation actually origins from inappropriate time-delayed kx–ω modulation, instead, for transverse OAM having inherent space-time coupling, immediate modulation is necessary. Thus, using immediate x–ω modulation, we demonstrate theoretically and experimentally degradation-free spatiotemporal Bessel (STB) vortices with transverse OAM even beyond 102. Remarkably, we observe a time-symmetrical evolution, verifying pure time diffraction on transverse OAM beams. More importantly, we quantify such nontrivial evolution as an intrinsic dispersion factor, opening the door towards time diffraction-free STB vortices via dispersion engineering. Our results may find analogues in other physical systems, such as surface plasmon-polaritons, superfluids, and Bose-Einstein condensates. It remains unclear whether transverse orbital angular momentum beams can maintain OAM values above 1. Here the authors demonstrate the generation of beams with transverse OAM up to 100 by the inverse design of phase and find an intrinsic dispersion factor to describe the nontrivial evolution of such beams.
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Affiliation(s)
- Wei Chen
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Wang Zhang
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yuan Liu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Fan-Chao Meng
- Institut FEMTO-ST, Université Bourgogne Franche-Comté CNRS UMR 6174, Besançon, 25000, France.,State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - John M Dudley
- Institut FEMTO-ST, Université Bourgogne Franche-Comté CNRS UMR 6174, Besançon, 25000, France
| | - Yan-Qing Lu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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Bran C, Fernandez-Roldan JA, del Real RP, Asenjo A, Chubykalo-Fesenko O, Vazquez M. Magnetic Configurations in Modulated Cylindrical Nanowires. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:600. [PMID: 33670880 PMCID: PMC7997473 DOI: 10.3390/nano11030600] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/12/2021] [Accepted: 02/21/2021] [Indexed: 11/18/2022]
Abstract
Cylindrical magnetic nanowires show great potential for 3D applications such as magnetic recording, shift registers, and logic gates, as well as in sensing architectures or biomedicine. Their cylindrical geometry leads to interesting properties of the local domain structure, leading to multifunctional responses to magnetic fields and electric currents, mechanical stresses, or thermal gradients. This review article is summarizing the work carried out in our group on the fabrication and magnetic characterization of cylindrical magnetic nanowires with modulated geometry and anisotropy. The nanowires are prepared by electrochemical methods allowing the fabrication of magnetic nanowires with precise control over geometry, morphology, and composition. Different routes to control the magnetization configuration and its dynamics through the geometry and magnetocrystalline anisotropy are presented. The diameter modulations change the typical single domain state present in cubic nanowires, providing the possibility to confine or pin circular domains or domain walls in each segment. The control and stabilization of domains and domain walls in cylindrical wires have been achieved in multisegmented structures by alternating magnetic segments of different magnetic properties (producing alternative anisotropy) or with non-magnetic layers. The results point out the relevance of the geometry and magnetocrystalline anisotropy to promote the occurrence of stable magnetochiral structures and provide further information for the design of cylindrical nanowires for multiple applications.
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Affiliation(s)
- Cristina Bran
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.A.F.-R.); (R.P.d.R.); (A.A.); (O.C.-F.); (M.V.)
| | - Jose Angel Fernandez-Roldan
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.A.F.-R.); (R.P.d.R.); (A.A.); (O.C.-F.); (M.V.)
- Department of Physics, University of Oviedo, 33007 Oviedo, Spain
| | - Rafael P. del Real
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.A.F.-R.); (R.P.d.R.); (A.A.); (O.C.-F.); (M.V.)
| | - Agustina Asenjo
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.A.F.-R.); (R.P.d.R.); (A.A.); (O.C.-F.); (M.V.)
| | - Oksana Chubykalo-Fesenko
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.A.F.-R.); (R.P.d.R.); (A.A.); (O.C.-F.); (M.V.)
| | - Manuel Vazquez
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.A.F.-R.); (R.P.d.R.); (A.A.); (O.C.-F.); (M.V.)
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Bran C, Fernandez-Roldan JA, P Del Real R, Asenjo A, Chen YS, Zhang J, Zhang X, Fraile Rodríguez A, Foerster M, Aballe L, Chubykalo-Fesenko O, Vazquez M. Unveiling the Origin of Multidomain Structures in Compositionally Modulated Cylindrical Magnetic Nanowires. ACS NANO 2020; 14:12819-12827. [PMID: 32970409 DOI: 10.1021/acsnano.0c03579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CoNi/Ni multisegmented cylindrical nanowires were synthesized via an electrochemical route. The wires are 140 nm in diameter, with 1000 nm long Ni segments and CoNi segments between 600 and 1400 nm in length. The magnetic configuration was imaged by XMCD-PEEM in the demagnetized state and at remanence after magnetizing axially and perpendicularly. Ni segments, with cubic crystal symmetry, show an axial magnetic configuration with a small curling component at the surface. In turn, CoNi segments, with hexagonal crystal symmetry and a strong magnetocrystalline anisotropy perpendicular to the nanowires, show a single vortex state in the shorter segments and multivortex or multitransverse magnetic configurations in medium and long segments, respectively. A detailed study by micromagnetic simulations reveals that the magnetic configuration is determined mainly by the coupling between soft Ni and harder CoNi segments. For short CoNi segments, Ni segments are magnetostatically coupled and the chirality of the single vortex formed in CoNi remains the same as that of the curling in neighboring Ni segments. For longer CoNi segments, the remanent state is either the multivortex or multitransverse state depending on whether the previously applied field was parallel or perpendicular to the magnetocrystalline axis. The results point out the relevance of the cylindrical geometry to promote the occurrence of complex magneto-chiral effects and provide key information for the design of cylindrical magnetic nanowires for multiple applications.
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Affiliation(s)
- Cristina Bran
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
| | - Jose Angel Fernandez-Roldan
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
- Department of Physics, University of Oviedo, Oviedo 33007, Spain
| | - Rafael P Del Real
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
| | - Agustina Asenjo
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
| | - Yu-Shen Chen
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
- Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan
| | - Junli Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Xixiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Arantxa Fraile Rodríguez
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociencia i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | | | - Lucia Aballe
- ALBA Synchrotron Light Facility, CELLS, Barcelona 08290, Spain
| | | | - Manuel Vazquez
- Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
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Fernández-Pacheco A, Skoric L, De Teresa JM, Pablo-Navarro J, Huth M, Dobrovolskiy OV. Writing 3D Nanomagnets Using Focused Electron Beams. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E3774. [PMID: 32859076 PMCID: PMC7503546 DOI: 10.3390/ma13173774] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/10/2020] [Accepted: 08/20/2020] [Indexed: 12/18/2022]
Abstract
Focused electron beam induced deposition (FEBID) is a direct-write nanofabrication technique able to pattern three-dimensional magnetic nanostructures at resolutions comparable to the characteristic magnetic length scales. FEBID is thus a powerful tool for 3D nanomagnetism which enables unique fundamental studies involving complex 3D geometries, as well as nano-prototyping and specialized applications compatible with low throughputs. In this focused review, we discuss recent developments of this technique for applications in 3D nanomagnetism, namely the substantial progress on FEBID computational methods, and new routes followed to tune the magnetic properties of ferromagnetic FEBID materials. We also review a selection of recent works involving FEBID 3D nanostructures in areas such as scanning probe microscopy sensing, magnetic frustration phenomena, curvilinear magnetism, magnonics and fluxonics, offering a wide perspective of the important role FEBID is likely to have in the coming years in the study of new phenomena involving 3D magnetic nanostructures.
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Affiliation(s)
- Amalio Fernández-Pacheco
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK;
| | - Luka Skoric
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK;
| | - José María De Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA) and Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain;
| | - Javier Pablo-Navarro
- Laboratorio de Microscopías Avanzadas (LMA) and Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain;
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Michael Huth
- Institute of Physics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
| | - Oleksandr V. Dobrovolskiy
- Institute of Physics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
- Faculty of Physics, University of Vienna, 1090 Vienna, Austria
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Perspective: Ferromagnetic Liquids. MATERIALS 2020; 13:ma13122712. [PMID: 32549201 PMCID: PMC7345949 DOI: 10.3390/ma13122712] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 12/22/2022]
Abstract
Mechanical jamming of nanoparticles at liquid-liquid interfaces has evolved into a versatile approach to structure liquids with solid-state properties. Ferromagnetic liquids obtain their physical and magnetic properties, including a remanent magnetization that distinguishes them from ferrofluids, from the jamming of magnetic nanoparticles assembled at the interface between two distinct liquids to minimize surface tension. This perspective provides an overview of recent progress and discusses future directions, challenges and potential applications of jamming magnetic nanoparticles with regard to 3D nano-magnetism. We address the formation and characterization of curved magnetic geometries, and spin frustration between dipole-coupled nanostructures, and advance our understanding of particle jamming at liquid-liquid interfaces.
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