1
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Li XL, Ma Z, Tang J. Recent Developments of Nontraditional Single-Molecule Toroics. Chemistry 2024; 30:e202304369. [PMID: 38414107 DOI: 10.1002/chem.202304369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 02/29/2024]
Abstract
Single-molecule toroics (SMTs), defined as a type of molecules with toroidal arrangement of magnetic moment associated with bi-stable non-magnetic ground states, are promising candidates for high-density information storage and the development of molecule based multiferroic materials with linear magneto-electric coupling and multiferroic behavior. The design and synthesis of SMTs by arranging the magnetic anisotropy axis in a circular pattern at the molecular level have been of great interest to scientists for last two decades since the first detection of the SMT behavior in the seminal Dy3 molecules. DyIII ion has long been the ideal candidate for constructing SMTs due to its Kramer ion nature as well as high anisotropy. Nevertheless, other LnIII ions such as TbIII and HoIII ions, as well as some paramagnetic transition metal ions, have also been used to construct many nontraditional SMTs. Therefore, we review the progress in the studies of SMTs based on the nontraditional perspective, ranging from the 3D topological to 1D&2D&3D polymeric SMTs, and 3d-4f to non Dy-based SMTs. We hope the understanding we provide about nontraditional SMTs will be helpful in designing novel SMTs.
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Affiliation(s)
- Xiao-Lei Li
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
| | - Zhifang Ma
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, P. R. China
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2
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Kong JF, Ren Y, Tey MSN, Ho P, Khoo KH, Chen X, Soumyanarayanan A. Quantifying the Magnetic Interactions Governing Chiral Spin Textures Using Deep Neural Networks. ACS Appl Mater Interfaces 2024; 16:1025-1032. [PMID: 38156820 DOI: 10.1021/acsami.3c12655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The interplay of magnetic interactions in chiral multilayer films gives rise to nanoscale topological spin textures that form attractive elements for next-generation computing. Quantifying these interactions requires several specialized, time-consuming, and resource-intensive experimental techniques. Imaging of ambient domain configurations presents a promising avenue for high-throughput extraction of parent magnetic interactions. Here, we present a machine learning (ML)-based approach to simultaneously determine the key magnetic interactions─symmetric exchange, chiral exchange, and anisotropy─governing the chiral domain phenomenology in multilayers, using a single binarized image of domain configurations. Our convolutional neural network model, trained and validated on over 10,000 domain images, achieved R2 > 0.85 in predicting the parameters and independently learned the physical interdependencies between magnetic parameters. When applied to microscopy data acquired across samples, our model-predicted parameter trends are consistent with those of independent experimental measurements. These results establish ML-driven techniques as valuable, high-throughput complements to conventional determination of magnetic interactions and serve to accelerate materials and device development for nanoscale electronics.
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Affiliation(s)
- Jian Feng Kong
- Agency for Science, Technology & Research (A*STAR), Institute of High Performance Computing, Singapore 138632, Singapore
| | - Yuhua Ren
- Department of Physics, National University of Singapore, Singapore 117551, Singapore
| | - M S Nicholas Tey
- Agency for Science, Technology & Research (A*STAR), Institute of Materials Research & Engineering, Singapore 138634, Singapore
| | - Pin Ho
- Agency for Science, Technology & Research (A*STAR), Institute of Materials Research & Engineering, Singapore 138634, Singapore
| | - Khoong Hong Khoo
- Agency for Science, Technology & Research (A*STAR), Institute of High Performance Computing, Singapore 138632, Singapore
| | - Xiaoye Chen
- Agency for Science, Technology & Research (A*STAR), Institute of Materials Research & Engineering, Singapore 138634, Singapore
| | - Anjan Soumyanarayanan
- Department of Physics, National University of Singapore, Singapore 117551, Singapore
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3
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Zhang F, Zhang J, Fang D, Zhang Y, Wang D. Unusual magnetic interaction in CrTe: insights from machine-learning and empirical models. J Phys Condens Matter 2023; 36:135804. [PMID: 38091625 DOI: 10.1088/1361-648x/ad154f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 12/13/2023] [Indexed: 12/28/2023]
Abstract
Chromium telluride (CrTe) has received much attention due to its small magnetic anisotropy, which hosts the potential for complex magnetic structures. However, its magnetic properties have been relatively unexplored with numerical simulations, as the magnetic interactions inside are quite unusual. In this study, we employ both a machine-learning model and an empirical model to investigate the magnetic phase transitions of bulk and monolayer CrTe, revealing the existence of unusual magnetic interaction, which can be captured by the machine-learning model but not the simple empirical model. Furthermore, our results also demonstrate that magnetic moments further apart exhibit stronger interactions than those in closer proximity, deviating from typical behavior.
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Affiliation(s)
- F Zhang
- School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
- Key Lab of Micro-Nano Electronics and System Integration of Xi'an City, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - J Zhang
- School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
- Key Lab of Micro-Nano Electronics and System Integration of Xi'an City, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - D Fang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Y Zhang
- School of Physics, Henan Normal University, Xinxiang 453007, People's Republic of China
| | - D Wang
- School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
- Key Lab of Micro-Nano Electronics and System Integration of Xi'an City, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
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4
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Kour M, Taborosi A, Boyd ES, Szilagyi RK. Development of molecular cluster models to probe pyrite surface reactivity. J Comput Chem 2023; 44:2486-2500. [PMID: 37650712 DOI: 10.1002/jcc.27213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023]
Abstract
The recent discovery that anaerobic methanogens can reductively dissolve pyrite and utilize dissolution products as a source of iron and sulfur to meet their biosynthetic demands for these elements prompted the development of atomic-scale nanoparticle models, as maquettes of reactive surface sites, for describing the fundamental redox steps that take place at the mineral surface during reduction. The given report describes our computational approach for modeling n(FeS2 ) nanoparticles originated from mineral bulk structure. These maquettes contain a comprehensive set of coordinatively unsaturated Fe(II) sites that are connected via a range of persulfide (S2 2- ) ligation. In addition to the specific maquettes with n = 8, 18, and 32 FeS2 units, we established guidelines for obtaining low-energy structures by considering the pattern of ionic, covalent, and magnetic interactions among the metal and ligand sites. The developed models serve as computational nano-reactors that can be used to describe the reductive dissolution mechanism of pyrite to better understand the reactive sites on the mineral, where microbial extracellular electron-transfer reactions can occur.
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Affiliation(s)
- Manjinder Kour
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Attila Taborosi
- Research Initiative for Supra-Materials, Faculty of Engineering, Shinshu University, Nagano, Japan
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Robert K Szilagyi
- Department of Chemistry, The University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
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5
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Ntallis N, Trohidou KN. Effect of Organic Coating Variation on the Electric and Magnetic Behavior of Ferrite Nanoparticles. ACS Phys Chem Au 2023; 3:532-539. [PMID: 38034033 PMCID: PMC10683492 DOI: 10.1021/acsphyschemau.3c00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 12/02/2023]
Abstract
Organic ligand coatings can modify the surface properties of nanoparticles. With the proper choice of the type of nanoparticles and of the ligand, a targeted modification can be achieved that is suitable for specific applications. In the present work, we employ density functional theory calculations with Hubbard corrections (DFT + U) to treat localized states in order to investigate the magnetic and electrostatic properties of ferrite nanoparticles (CoFe2O4 and Fe2O3) covered with COOH-terminated [oleic acid (OA)] and OH-terminated [diethylene glycol (DEG)] ligands by varying the ligands coverage. OA results in a decrease of the mean magnetic moment for both particles as the coating coverage increases. The magnetic anisotropy (MAE) significantly decreases for CoFe2O4, whereas for Fe2O3 a significant increase of MAE is found as the OA coverage percentage increases. For DEG, the variation of both types of nanoparticles in the magnetic moment and the magnetic anisotropy is not significant since DEG shows a weaker attachment on the surface. As COOH shows a larger percentage of covalent bonding than OH, a larger amount of charge is transferred to both particles when OA is attached on their surface. In this case, the particles possess a higher charge, and thus they can produce a larger electrostatic potential in the neighborhood independently of the screening by the coating. Thus, the repulsive Coulombic forces are enhanced mainly in the OA coating case, resulting in an enhancement of their colloidal stability.
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Affiliation(s)
- Nikolaos Ntallis
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, Agia Paraskevi, Attiki 153 10, Greece
| | - Kalliopi N. Trohidou
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, Agia Paraskevi, Attiki 153 10, Greece
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6
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Paddison JAM. Spinteract: a program to refine magnetic interactions to diffuse scattering data. J Phys Condens Matter 2023; 35. [PMID: 37604160 DOI: 10.1088/1361-648x/acf261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 08/21/2023] [Indexed: 08/23/2023]
Abstract
Magnetic diffuse scattering-the broad magnetic scattering features observed in neutron-diffraction data above a material's magnetic ordering temperature-provides a rich source of information about the material's magnetic Hamiltonian. However, this information has often remained under-utilised due to a lack of available computer software that can fit values of magnetic interaction parameters to such data. Here, an open-source computer program, Spinteract, is presented, which enables straightforward refinement of magnetic interaction parameters to powder and single-crystal magnetic diffuse scattering data. The theory and implementation of this approach are summarised. Examples are presented of refinements to published experimental diffuse-scattering data sets for the canonical antiferromagnet MnO and the highly-frustrated classical spin liquid Gd3Ga5O12. Guidelines for data collection and refinement are outlined, and possible developments of the approach are discussed.
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Affiliation(s)
- Joseph A M Paddison
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
- Churchill College, University of Cambridge, Storey's Way, Cambridge CB3 0DS, United Kingdom
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7
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de Oteyza DG, Frederiksen T. Carbon-based nanostructures as a versatile platform for tunable π-magnetism. J Phys Condens Matter 2022; 34:443001. [PMID: 35977474 DOI: 10.1088/1361-648x/ac8a7f] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Emergence ofπ-magnetism in open-shell nanographenes has been theoretically predicted decades ago but their experimental characterization was elusive due to the strong chemical reactivity that makes their synthesis and stabilization difficult. In recent years, on-surface synthesis under vacuum conditions has provided unprecedented opportunities for atomically precise engineering of nanographenes, which in combination with scanning probe techniques have led to a substantial progress in our capabilities to realize localized electron spin states and to control electron spin interactions at the atomic scale. Here we review the essential concepts and the remarkable advances in the last few years, and outline the versatility of carbon-basedπ-magnetic materials as an interesting platform for applications in spintronics and quantum technologies.
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Affiliation(s)
- Dimas G de Oteyza
- Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA, E-33940 El Entrego, Spain
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, E-48013 Bilbao, Spain
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8
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Abbas H, Nadeem K, Hester J, Pervez MF, Yick S, Kostylev M, Letofsky-Papst I, Ali B, Ulrich C, Krenn H. Competing magnetic states and M- Hloop splitting in core-shell NiO nanoparticles. Nanotechnology 2022; 33:345711. [PMID: 35525188 DOI: 10.1088/1361-6528/ac6dc3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 05/06/2022] [Indexed: 06/14/2023]
Abstract
Magnetic relaxation in a nanoparticles system depends on the intra-particle interactions, reversal mechanism, the anisotropy field, easy axis distribution, particle volume, lattice defects, surface defects, materials composite, etc. Here we report the competing magnetic states between superparamagnetic blocking and Néel transition states in 14 nm core-shell NiO nanoparticles. A crossover temperature of 50 K was observed for both these states from the zero field cooled/field cooled magnetization curves taken at different fields. At crossover temperature, an interestingM-Hloop splitting is observed which is attributed to the slow spin relaxation. This anomalousM-Hloop splitting behaviour was found to be particle size dependent and suppressed for diameters above and below 14 nm which indicates a critical size for these competing magnetic states. Additional neutron diffraction experiments confirmed this observation. This experimental study provides a new insight for the understanding of intra-particle interactions in fine antiferromagnetic nanoparticles and obtained results are an important step towards deeper understanding of the competing/non-competing modes between superparamagnetic blocked and Néel transition states.
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Affiliation(s)
- Hur Abbas
- Nanoscience and Technology Laboratory, Department of Physics, International Islamic University, Islamabad 44000, Pakistan
| | - K Nadeem
- Nanoscience and Technology Laboratory, Department of Physics, International Islamic University, Islamabad 44000, Pakistan
| | - J Hester
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights NSW 2234, Australia
| | - M F Pervez
- School of Physics, The University of New South Wales, Kensington NSW 2052, Australia
| | - S Yick
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights NSW 2234, Australia
- School of Physics, The University of New South Wales, Kensington NSW 2052, Australia
| | - M Kostylev
- School of Physics, The University of Western Australia, Crawley, WA 6009, Australia
| | - Ilse Letofsky-Papst
- Institute of Electron Microscopy, University of Technology Graz, Steyrergasse 17, A-8010 Graz, Austria
| | - B Ali
- Nanoscience and Technology Laboratory, Department of Physics, International Islamic University, Islamabad 44000, Pakistan
| | - C Ulrich
- School of Physics, The University of New South Wales, Kensington NSW 2052, Australia
| | - H Krenn
- Institute of Physics, Karl-Franzens University, Universitätsplatz 5, A-8010 Graz, Austria
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9
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Khurshid H, Yoosuf R, Issa BA, Attaelmanan AG, Hadjipanayis G. Tuning Easy Magnetization Direction and Magnetostatic Interactions in High Aspect Ratio Nanowires. Nanomaterials (Basel) 2021; 11:nano11113042. [PMID: 34835808 PMCID: PMC8621815 DOI: 10.3390/nano11113042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/25/2022]
Abstract
Cobalt nanowires have been synthesized by electrochemical deposition using track-etched anodized aluminum oxide (AAO) templates. Nanowires with varying spacing-to-diameter ratios were prepared, and their magnetic properties were investigated. It is found that the nanowires’ easy magnetization direction switches from parallel to perpendicular to the nanowire growth direction when the nanowire’s spacing-to-diameter ratio is reduced below 0.7, or when the nanowires’ packing density is increased above 5%. Upon further reduction in the spacing-to-diameter ratio, nanowires’ magnetic properties exhibit an isotropic behavior. Apart from shape anisotropy, strong dipolar interactions among nanowires facilitate additional uniaxial anisotropy, favoring an easy magnetization direction perpendicular to their growth direction. The magnetic interactions among the nanowires were studied using the standard method of remanence curves. The demagnetization curves and Delta m (Δm) plots showed that the nanowires interact via dipolar interactions that act as an additional uniaxial anisotropy favoring an easy magnetization direction perpendicular to the nanowire growth direction. The broadening of the dipolar component of Δm plots indicate an increase in the switching field distribution with the increase in the nanowires’ diameter. Our findings provide an important insight into the magnetic behavior of cobalt nanowires, meaning that it is crucial to design them according to the specific requirements for the application purposes.
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Affiliation(s)
- Hafsa Khurshid
- Department of Applied Physics and Astronomy, University of Sharjah, Sharjah 27272, United Arab Emirates; (R.Y.); (A.G.A.)
- Department of Radiology, Dartmouth Hitchcock Medical Center, Lebanon, NH 03766, USA
- Department of Medical Diagnostic Imaging, University of Sharjah, Sharjah 27272, United Arab Emirates;
- Correspondence: ; Tel.: +971-50-726-0807
| | - Rahana Yoosuf
- Department of Applied Physics and Astronomy, University of Sharjah, Sharjah 27272, United Arab Emirates; (R.Y.); (A.G.A.)
| | - Bashar Afif Issa
- Department of Medical Diagnostic Imaging, University of Sharjah, Sharjah 27272, United Arab Emirates;
| | - Atta G. Attaelmanan
- Department of Applied Physics and Astronomy, University of Sharjah, Sharjah 27272, United Arab Emirates; (R.Y.); (A.G.A.)
| | - George Hadjipanayis
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA;
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10
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Ovejero JG, Spizzo F, Morales MP, Del Bianco L. Nanoparticles for Magnetic Heating: When Two (or More) Is Better Than One. Materials (Basel) 2021; 14:6416. [PMID: 34771940 PMCID: PMC8585339 DOI: 10.3390/ma14216416] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 01/16/2023]
Abstract
The increasing use of magnetic nanoparticles as heating agents in biomedicine is driven by their proven utility in hyperthermia therapeutic treatments and heat-triggered drug delivery methods. The growing demand of efficient and versatile nanoheaters has prompted the creation of novel types of magnetic nanoparticle systems exploiting the magnetic interaction (exchange or dipolar in nature) between two or more constituent magnetic elements (magnetic phases, primary nanoparticles) to enhance and tune the heating power. This process occurred in parallel with the progress in the methods for the chemical synthesis of nanostructures and in the comprehension of magnetic phenomena at the nanoscale. Therefore, complex magnetic architectures have been realized that we classify as: (a) core/shell nanoparticles; (b) multicore nanoparticles; (c) linear aggregates; (d) hybrid systems; (e) mixed nanoparticle systems. After a general introduction to the magnetic heating phenomenology, we illustrate the different classes of nanoparticle systems and the strategic novelty they represent. We review some of the research works that have significantly contributed to clarify the relationship between the compositional and structural properties, as determined by the synthetic process, the magnetic properties and the heating mechanism.
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Affiliation(s)
- Jesus G. Ovejero
- Departamento de Energía, Medio Ambiente y Salud, Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain; (J.G.O.); (M.P.M.)
- Servicio de Dosimetría y Radioprotección, Hospital General Universitario Gregorio Marañón, E-28007 Madrid, Spain
| | - Federico Spizzo
- Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, I-44122 Ferrara, Italy;
| | - M. Puerto Morales
- Departamento de Energía, Medio Ambiente y Salud, Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain; (J.G.O.); (M.P.M.)
| | - Lucia Del Bianco
- Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, I-44122 Ferrara, Italy;
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Amoroso D, Barone P, Picozzi S. Interplay between Single-Ion and Two-Ion Anisotropies in Frustrated 2D Semiconductors and Tuning of Magnetic Structures Topology. Nanomaterials (Basel) 2021; 11:nano11081873. [PMID: 34443704 PMCID: PMC8397980 DOI: 10.3390/nano11081873] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 01/14/2023]
Abstract
The effects of competing magnetic interactions in stabilizing different spin configurations are drawing renewed attention in order to unveil emerging topological spin textures and to highlight microscopic mechanisms leading to their stabilization. The possible key role of the two-site exchange anisotropy in selecting specific helicity and vorticity of skyrmionic lattices has only recently been proposed. In this work, we explore the phase diagram of a frustrated localized magnet characterized by a two-dimensional centrosymmetric triangular lattice, focusing on the interplay between the two-ion anisotropy and the single-ion anisotropy. The effects of an external magnetic field applied perpendicularly to the magnetic layer, are also investigated. By means of Monte Carlo simulations, we find an abundance of different spin configurations, going from trivial to high-order Q skyrmionic and meronic lattices. In closer detail, we find that a dominant role is played by the two-ion over the single-ion anisotropy in determining the planar spin texture; the strength and the sign of single ion anisotropy, together with the magnitude of the magnetic field, tune the perpendicular spin components, mostly affecting the polarity (and, in turn, the topology) of the spin texture. Our analysis confirms the crucial role of the anisotropic symmetric exchange in systems with dominant short-range interactions; at the same time, we predict a rich variety of complex magnetic textures, which may arise from a fine tuning of competing anisotropic mechanisms.
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Affiliation(s)
- Danila Amoroso
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi “G. D’Annunzio”, I-66100 Chieti, Italy;
- Correspondence:
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche CNR-SPIN, Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere 100, I-00133 Rome, Italy;
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi “G. D’Annunzio”, I-66100 Chieti, Italy;
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12
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Karshalev E, Silva-Lopez C, Chan K, Yan J, Sandraz E, Gallot M, Nourhani A, Garay J, Wang J. Swimmers Heal on the Move Following Catastrophic Damage. Nano Lett 2021; 21:2240-2247. [PMID: 33617270 DOI: 10.1021/acs.nanolett.0c05061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Herein, we describe the development of 2D self-healing small-scale swimmers capable of autonomous propulsion and "on-the-fly" structural recovery in large containers. Incorporation of magnetic Nd2Fe14B microparticles in specialized printed strips results in rapid reorientation and reattachment of the moving tail to its complementary broken static piece to restore the original swimmer structure and propulsion behavior. The swimmers display functional recovery independent of user input. Measurements of the magnetic hysteresis and fields were used to assess the behavior of the healing mechanism in real swimming situations. Damage position and multiple magnetic strip patterns have been examined and their influence upon the recovery efficiency has been compared. Owing to its versatility, fast response, and simplicity the new self-healing strategy represents an important step toward the development of new "on-the-fly" repairing strategies for small-scale swimmers and robots.
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Affiliation(s)
- Emil Karshalev
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
| | - Cristian Silva-Lopez
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
| | - Kyle Chan
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Jieming Yan
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
| | - Elodie Sandraz
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
| | - Mathieu Gallot
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
| | - Amir Nourhani
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
| | - Javier Garay
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Joseph Wang
- Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States
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13
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Abstract
This topical review presents an overview of the recent experimental and theoretical attempts on designing magnonic crystals for operation at different frequencies. The focus is put on the microscopic physical mechanisms involved in the formation of the magnonic band structure, allowed as well as forbidden magnon states in various systems, including ultrathin films, multilayers and artificial magnetic structures. The essential criteria for the formation of magnonic bandgaps in different frequency regimes are explained in connection with the magnon dynamics in such structures. The possibility of designing small-size magnonic crystals for operation at ultrahigh frequencies (terahertz and sub-terahertz regime) is discussed. Recently discovered magnonic crystals based on topological defects and using periodic Dzyaloshinskii-Moriya interaction, are outlined. Different types of magnonic crystals, capable of operation at different frequency regimes, are put within a rather unified picture.
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Affiliation(s)
- Khalil Zakeri
- Heisenberg Spin-dynamics Group, Physikalisches Institut, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe, Germany
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14
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Kuznetsov AA. Zero-Field and Field-Induced Interactions between Multicore Magnetic Nanoparticles. Nanomaterials (Basel) 2019; 9:E718. [PMID: 31075888 DOI: 10.3390/nano9050718] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/02/2019] [Accepted: 05/05/2019] [Indexed: 02/03/2023]
Abstract
In this paper, the Langevin dynamics simulation method is used to study magnetic interactions between a pair of multicore magnetic nanoparticles subjected to a uniform magnetic field. Multicore nanoparticles are modelled as spherical rigid clusters of single-domain superparamagnetic cores coupled via dipole-dipole interactions. It is shown that the magnetic force between two well-separated clusters in a strong applied field can be accurately described within the induced point-dipole approximation. However, this approximation also assumes that there are no interactions between clusters in the zero-field limit. On the contrary, simulations indicate the existence of a relatively small attractive magnetic force between clusters, even in the absence of an applied field. It is shown that this force is a direct superparamagnetic analog of the van der Waals interaction between a pair of dielectric spheres.
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15
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Grijalva-Castillo MC, Santillán-Rodríguez CR, Sáenz-Hernández RJ, Botello-Zubíate ME, Matutes-Aquino JA. First Order Reversal Curve Study of SmFe₂ Melt-Spun Ribbons. Materials (Basel) 2018; 11:ma11101804. [PMID: 30249010 PMCID: PMC6212980 DOI: 10.3390/ma11101804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/12/2018] [Accepted: 09/20/2018] [Indexed: 06/08/2023]
Abstract
First-order reversal curves (FORC) and the FORC distribution provide a detailed characterization of the relative proportions of reversible and irreversible components of the magnetization of a material, revealing the dominant interactions in the system. Alloys with the nominal composition SmFe₂ were obtained by melt-spinning with a cooper wheel velocity of 30 m/s. X-ray powder diffraction analysis showed a greater part consisting of an amorphous phase and a very small amount of SmFe₂ crystalline phase with an average crystallite size of 8 nm. A constant acceleration Mössbauer spectrum, measured at room temperature in transmission mode, was fitted to a continuous distribution of effective fields at the nucleus of the amorphous phase (about 84% of the total area), plus two sextets for the non-equivalent sites of Fe in the SmFe₂ crystalline phase. 91 first-order reversal curves were collected in a Quantum Design PPMS-VSM with reversal fields from ⁻800 mT to +800 mT and using a calibration field of 850 mT. The obtained FORC diagrams showed a combined effect of a local interaction field and a mean interaction field, and showed that the reversible magnetization is a function of both, the applied magnetic field and the irreversible magnetization.
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Affiliation(s)
- María C Grijalva-Castillo
- CONACYT-Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31136, Mexico.
| | - Carlos R Santillán-Rodríguez
- Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31136, Mexico.
| | - Renee J Sáenz-Hernández
- Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31136, Mexico.
| | - María E Botello-Zubíate
- Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31136, Mexico.
| | - José A Matutes-Aquino
- Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31136, Mexico.
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16
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Moraes S, Navas D, Béron F, Proenca MP, Pirota KR, Sousa CT, Araújo JP. The Role of Cu Length on the Magnetic Behaviour of Fe/Cu Multi-Segmented Nanowires. Nanomaterials (Basel) 2018; 8:E490. [PMID: 29973506 PMCID: PMC6071036 DOI: 10.3390/nano8070490] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 06/29/2018] [Accepted: 07/02/2018] [Indexed: 11/26/2022]
Abstract
A set of multi-segmented Fe/Cu nanowires were synthesized by a two-step anodization process of aluminum substrates and a pulsed electrodeposition technique using a single bath. While both Fe segment length and diameter were kept constant to (30 ± 7) and (45 ± 5) nm, respectively, Cu length was varied between (15 ± 5) and (120 ± 10) nm. The influence of the non-magnetic layer thickness variation on the nanowire magnetic properties was investigated through first-order reversal curve (FORC) measurements and micromagnetic simulations. Our analysis confirmed that, in the multi-segmented Fe/Cu nanowires with shorter Cu segments, the dipolar coupling between Fe segments controls the nanowire magnetic behavior, and its performance is like that of a homogenous Fe nanowire array of similar dimensions. On the other hand, multi-segmented Fe/Cu nanowires with larger Cu segments act like a collection of non-interacting magnetic entities (along the nanowire axis), and their global behavior is mainly controlled by the neighbor-to-neighbor nanodisc dipolar interactions.
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Affiliation(s)
- Suellen Moraes
- Instituto de Física dos Materiais da Universidade do Porto-Instituto de Nanotecnologia and Department Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
| | - David Navas
- Instituto de Física dos Materiais da Universidade do Porto-Instituto de Nanotecnologia and Department Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
| | - Fanny Béron
- Instituto de Física Gleb Wataghin (IFGW), Universidade Estadual de Campinas (UNICAMP), Campinas, SP 13083-859, Brazil.
| | - Mariana P Proenca
- Instituto de Física dos Materiais da Universidade do Porto-Instituto de Nanotecnologia and Department Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
- Instituto de Sistemas Optoelectrónicos y Microtecnología, Universidad Politécnica de Madrid, Avda., Complutense 30, E-28040 Madrid, Spain.
| | - Kleber R Pirota
- Instituto de Física Gleb Wataghin (IFGW), Universidade Estadual de Campinas (UNICAMP), Campinas, SP 13083-859, Brazil.
| | - Célia T Sousa
- Instituto de Física dos Materiais da Universidade do Porto-Instituto de Nanotecnologia and Department Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
| | - João P Araújo
- Instituto de Física dos Materiais da Universidade do Porto-Instituto de Nanotecnologia and Department Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
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17
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Trisnanto SB, Takemura Y. Complex Magnetization Harmonics of Polydispersive Magnetic Nanoclusters. Nanomaterials (Basel) 2018; 8:E424. [PMID: 29891808 DOI: 10.3390/nano8060424] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 11/16/2022]
Abstract
Understanding magnetic interparticle interactions within a single hydrodynamic volume of polydispersed magnetic nanoparticles and the resulting nonlinear magnetization properties is critical for their implementation in magnetic theranostics. However, in general, the field-dependent static and dynamic magnetization measurements may only highlight polydispersity effects including magnetic moment and size distributions. Therefore, as a complement to such typical analysis of hysteretic magnetization curves, we spectroscopically examined the complex magnetization harmonics of magnetic nanoclusters either dispersed in a liquid medium or immobilized by a hydrocolloid polymer, later to emphasize the harmonic characteristics for different core sizes. In the case of superparamagnetic nanoclusters with a 4-nm primary size, particularly, we correlated the negative quadrature components of the third-harmonic susceptibility with an insignificant cluster rotation induced by the oscillatory field. Moreover, the field-dependent in-phase components appear to be frequency-independent, suggesting a weak damping effect on the moment dynamics. The characteristic of the Néel time constant further supports this argument by showing a smaller dependence on the applied dc bias field, in comparison to that of larger cores. These findings show that the complex harmonic components of the magnetization are important attributes to the interacting cores of a magnetic nanocluster.
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18
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Cabrera D, Coene A, Leliaert J, Artés-Ibáñez EJ, Dupré L, Telling ND, Teran FJ. Dynamical Magnetic Response of Iron Oxide Nanoparticles Inside Live Cells. ACS Nano 2018; 12:2741-2752. [PMID: 29508990 DOI: 10.1021/acsnano.7b08995] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Magnetic nanoparticles exposed to alternating magnetic fields have shown a great potential acting as magnetic hyperthermia mediators for cancer treatment. However, a dramatic and unexplained reduction of the nanoparticle magnetic heating efficiency has been evidenced when nanoparticles are located inside cells or tissues. Recent studies suggest the enhancement of nanoparticle clustering and/or immobilization after interaction with cells as possible causes, although a quantitative description of the influence of biological matrices on the magnetic response of magnetic nanoparticles under AC magnetic fields is still lacking. Here, we studied the effect of cell internalization on the dynamical magnetic response of iron oxide nanoparticles (IONPs). AC magnetometry and magnetic susceptibility measurements of two magnetic core sizes (11 and 21 nm) underscored differences in the dynamical magnetic response following cell uptake with effects more pronounced for larger sizes. Two methodologies have been employed for experimentally determining the magnetic heat losses of magnetic nanoparticles inside live cells without risking their viability as well as the suitability of magnetic nanostructures for in vitro hyperthermia studies. Our experimental results-supported by theoretical calculations-reveal that the enhancement of intracellular IONP clustering mainly drives the cell internalization effects rather than intracellular IONP immobilization. Understanding the effects related to the nanoparticle transit into live cells on their magnetic response will allow the design of nanostructures containing magnetic nanoparticles whose dynamical magnetic response will remain invariable in any biological environments, allowing sustained and predictable in vivo heating efficiency.
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Affiliation(s)
- David Cabrera
- iMdea Nanociencia , Campus Universitario de Cantoblanco, C\Faraday, 9 , 28049 Madrid , Spain
- Institute for Science and Technology in Medicine , Keele University , Guy Hilton Research Centre, Thornburrow Drive , Hartshill, Stoke-on-Trent ST4 7QB , United Kingdom
| | - Annelies Coene
- Department of Electrical Energy, Metals, Mechanical Constructions and Systems , Ghent University , Technologiepark 913 , 9052 Zwijnaarde , Belgium
| | - Jonathan Leliaert
- Department of Solid State Sciences , Ghent University , Krijgslaan 281/S1 , 9000 Ghent , Belgium
| | - Emilio J Artés-Ibáñez
- iMdea Nanociencia , Campus Universitario de Cantoblanco, C\Faraday, 9 , 28049 Madrid , Spain
| | - Luc Dupré
- Department of Electrical Energy, Metals, Mechanical Constructions and Systems , Ghent University , Technologiepark 913 , 9052 Zwijnaarde , Belgium
| | - Neil D Telling
- Institute for Science and Technology in Medicine , Keele University , Guy Hilton Research Centre, Thornburrow Drive , Hartshill, Stoke-on-Trent ST4 7QB , United Kingdom
| | - Francisco J Teran
- iMdea Nanociencia , Campus Universitario de Cantoblanco, C\Faraday, 9 , 28049 Madrid , Spain
- Nanobiotecnología (iMdea-Nanociencia) , Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid , Spain
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19
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Spizzo F, Sgarbossa P, Sieni E, Semenzato A, Dughiero F, Forzan M, Bertani R, Del Bianco L. Synthesis of Ferrofluids Made of Iron Oxide Nanoflowers: Interplay between Carrier Fluid and Magnetic Properties. Nanomaterials (Basel) 2017; 7:E373. [PMID: 29113079 DOI: 10.3390/nano7110373] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/01/2017] [Indexed: 11/17/2022]
Abstract
Ferrofluids are nanomaterials consisting of magnetic nanoparticles that are dispersed in a carrier fluid. Their physical properties, and hence their field of application are determined by intertwined compositional, structural, and magnetic characteristics, including interparticle magnetic interactions. Magnetic nanoparticles were prepared by thermal decomposition of iron(III) chloride hexahydrate (FeCl₃·6H₂O) in 2-pyrrolidone, and were then dispersed in two different fluids, water and polyethylene glycol 400 (PEG). A number of experimental techniques (especially, transmission electron microscopy, Mössbauer spectroscopy and superconducting quantum interference device (SQUID) magnetometry) were employed to study both the as-prepared nanoparticles and the ferrofluids. We show that, with the adopted synthesis parameters of temperature and FeCl₃ relative concentration, nanoparticles are obtained that mainly consist of maghemite and present a high degree of structural disorder and strong spin canting, resulting in a low saturation magnetization (~45 emu/g). A remarkable feature is that the nanoparticles, ultimately due to the presence of 2-pyrrolidone at their surface, are arranged in nanoflower-shape structures, which are substantially stable in water and tend to disaggregate in PEG. The different arrangement of the nanoparticles in the two fluids implies a different strength of dipolar magnetic interactions, as revealed by the analysis of their magnetothermal behavior. The comparison between the magnetic heating capacities of the two ferrofluids demonstrates the possibility of tailoring the performances of the produced nanoparticles by exploiting the interplay with the carrier fluid.
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20
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Hauptmann N, Gerritsen JW, Wegner D, Khajetoorians AA. Sensing Noncollinear Magnetism at the Atomic Scale Combining Magnetic Exchange and Spin-Polarized Imaging. Nano Lett 2017; 17:5660-5665. [PMID: 28782956 PMCID: PMC5599874 DOI: 10.1021/acs.nanolett.7b02538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/24/2017] [Indexed: 06/07/2023]
Abstract
Storing and accessing information in atomic-scale magnets requires magnetic imaging techniques with single-atom resolution. Here, we show simultaneous detection of the spin-polarization and exchange force with or without the flow of current with a new method, which combines scanning tunneling microscopy and noncontact atomic force microscopy. To demonstrate the application of this new method, we characterize the prototypical nanoskyrmion lattice formed on a monolayer of Fe/Ir(111). We resolve the square magnetic lattice by employing magnetic exchange force microscopy, demonstrating its applicability to noncollinear magnetic structures for the first time. Utilizing distance-dependent force and current spectroscopy, we quantify the exchange forces in comparison to the spin-polarization. For strongly spin-polarized tips, we distinguish different signs of the exchange force that we suggest arises from a change in exchange mechanisms between the probe and a skyrmion. This new approach may enable both nonperturbative readout combined with writing by current-driven reversal of atomic-scale magnets.
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21
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Zhang J, Agramunt-Puig S, Del-Valle N, Navau C, Baró MD, Estradé S, Peiró F, Pané S, Nelson BJ, Sanchez A, Nogués J, Pellicer E, Sort J. Tailoring Staircase-like Hysteresis Loops in Electrodeposited Trisegmented Magnetic Nanowires: a Strategy toward Minimization of Interwire Interactions. ACS Appl Mater Interfaces 2016; 8:4109-4117. [PMID: 26804742 DOI: 10.1021/acsami.5b11747] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A new strategy to minimize magnetic interactions between nanowires (NWs) dispersed in a fluid is proposed. Such a strategy consists of preparing trisegmented NWs containing two antiparallel ferromagnetic segments with dissimilar coercivity separated by a nonmagnetic spacer. The trisegmented NWs exhibit a staircase-like hysteresis loop with tunable shape that depends on the relative length of the soft- and hard-magnetic segments and the respective values of saturation magnetization. Such NWs are prepared by electrodepositing CoPt/Cu/Ni in a polycarbonate (PC) membrane. The antiparallel alignment is set by applying suitable magnetic fields while the NWs are still embedded in the PC membrane. Analytic calculations are used to demonstrate that the interaction magnetic energy from fully compensated trisegmented NWs with antiparallel alignment is reduced compared to a single-component NW with the same length or the trisegmented NWs with the two ferromagnetic counterparts parallel to each other. The proposed approach is appealing for the use of magnetic NWs in certain biological or catalytic applications where the aggregation of NWs is detrimental for optimized performance.
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Affiliation(s)
- Jin Zhang
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Sebastià Agramunt-Puig
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Núria Del-Valle
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Carles Navau
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Maria D Baró
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Sònia Estradé
- LENS, MIND-IN2UB, Departament d'Electrònica, Universitat de Barcelona , Martí i Franquès 1, E-08028 Barcelona, Spain
| | - Francesca Peiró
- LENS, MIND-IN2UB, Departament d'Electrònica, Universitat de Barcelona , Martí i Franquès 1, E-08028 Barcelona, Spain
| | - Salvador Pané
- Institute of Robotics & Intelligent Systems (IRIS), ETH Zürich , CH-8092 Zurich, Switzerland
| | - Bradley J Nelson
- Institute of Robotics & Intelligent Systems (IRIS), ETH Zürich , CH-8092 Zurich, Switzerland
| | - Alvaro Sanchez
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Josep Nogués
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) , Barcelona, Catalonia, Spain
| | - Eva Pellicer
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
| | - Jordi Sort
- Departament de Fı́sica, Universitat Autònoma de Barcelona , Bellaterra, E-08193 Barcelona, Catalonia, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) , Barcelona, Catalonia, Spain
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Andreu I, Natividad E, Solozábal L, Roubeau O. Nano-objects for addressing the control of nanoparticle arrangement and performance in magnetic hyperthermia. ACS Nano 2015; 9:1408-19. [PMID: 25658023 DOI: 10.1021/nn505781f] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
One current challenge of magnetic hyperthermia is achieving therapeutic effects with a minimal amount of nanoparticles, for which improved heating abilities are continuously pursued. However, it is demonstrated here that the performance of magnetite nanocubes in a colloidal solution is reduced by 84% when they are densely packed in three-dimensional arrangements similar to those found in cell vesicles after nanoparticle internalization. This result highlights the essential role played by the nanoparticle arrangement in heating performance, uncontrolled in applications. A strategy based on the elaboration of nano-objects able to confine nanocubes in a fixed arrangement is thus considered here to improve the level of control. The obtained specific absorption rate results show that nanoworms and nanospheres with fixed one- and two-dimensional nanocube arrangements, respectively, succeed in reducing the loss of heating power upon agglomeration, suggesting a change in the kind of nano-object to be used in magnetic hyperthermia.
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Affiliation(s)
- Irene Andreu
- Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza , Campus Río Ebro, María de Luna 3, 50018 Zaragoza, Spain
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23
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Poleti D, Rogan J, Rodić MV, Radovanović L. Mixed-ligand MnII and CuII complexes with alternating 2,2'-bipyrimidine and terephthalate bridges. Acta Crystallogr C Struct Chem 2015; 71:110-5. [PMID: 25652277 DOI: 10.1107/s2053229614028113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/24/2014] [Indexed: 11/10/2022]
Abstract
The novel polymeric complexes catena-poly[[diaquamanganese(II)]-μ-2,2'-bipyrimidine-κ(4)N(1),N(1'):N(3),N(3')-[diaquamanganese(II)]-bis(μ-terephthalato-κ(2)O(1):O(4))], [Mn2(C8H4O4)2(C8H6N4)(H2O)4]n, (I), and catena-poly[[[aquacopper(II)]-μ-aqua-μ-hydroxido-μ-terephthalato-κ(2)O(1):O(1')-copper(II)-μ-aqua-μ-hydroxido-μ-terephthalato-κ(2)O(1):O(1')-[aquacopper(II)]-μ-2,2'-bipyrimidine-κ(4)N(1),N(1'):N(3),N(3')] tetrahydrate], {[Cu3(C8H4O4)2(OH)2(C8H6N4)(H2O)4]·4H2O}n, (II), containing bridging 2,2'-bipyrimidine (bpym) ligands coordinated as bis-chelates, have been prepared via a ligand-exchange reaction. In both cases, quite unusual coordination modes of the terephthalate (tpht(2-)) anions were found. In (I), two tpht(2-) anions acting as bis-monodentate ligands bridge the Mn(II) centres in a parallel fashion. In (II), the tpht(2-) anions act as endo-bridges and connect two Cu(II) centres in combination with additional aqua and hydroxide bridges. In this way, the binuclear [Mn2(tpht)2(bpym)(H2O)4] entity in (I) and the trinuclear [Cu3(tpht)2(OH)2(bpym)(H2O)4]·4H2O coordination entity in (II) build up one-dimensional polymeric chains along the b axis. In (I), the Mn(II) cation lies on a twofold axis, whereas the four central C atoms of the bpym ligand are located on a mirror plane. In (II), the central Cu(II) cation is also on a special position (site symmetry -1). In the crystal structures, the packing of the chains is further strengthened by a system of hydrogen bonds [in both (I) and (II)] and weak face-to-face π-π interactions [in (I)], forming three-dimensional metal-organic frameworks. The Mn(II) cation in (I) has a trigonally deformed octahedral geometry, whereas the Cu(II) cations in (II) are in distorted octahedral environments. The Cu(II) polyhedra are inclined relative to each other and share common edges.
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Affiliation(s)
- Dejan Poleti
- Department of General and Inorganic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - Jelena Rogan
- Department of General and Inorganic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - Marko V Rodić
- Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia
| | - Lidija Radovanović
- Innovation Center, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
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Abstract
Molecular magnetism is a new and extremely fascinating field on the borders of chemistry, physics and materials science. The design and synthesis of molecule-based magnets requires the chemist to exert considerable control over the molecules to arrange them appropriately. It also demands the development of new theories to explain the complex magneto-structural behaviour of these intriguing solids. Molecular magnetism is still at a very early stage of development. The main challenge is to increase the strength of the magnetic interactions between spin carriers so the resulting materials can be usable at room temperature. However molecular magnets exhibit true potential to become multifunctional materials. They show some considerable advantages over conventional magnets: optical transparency, chemical sensitivity and low weight to name just a few. The following article is not a complete review of the field. Its aim is rather to show how beautiful and versatile magnetic molecular solids can be, and to encourage the in-depth study of the subject.
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Affiliation(s)
- Dawid Pinkowicz
- Jagiellonian University, Institute of Molecular Magnetism. Laboratory of Molecular Magnetism, University of Florence, Ingardena 3, 30-060, Kraków, Poland
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25
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Packer EL, Sternlicht H, Rabinowitz JC. The possible role of aromatic residues of Clostridium acidi-urici ferredoxin in electron transport. Proc Natl Acad Sci U S A 1972; 69:3278-82. [PMID: 4508321 PMCID: PMC389753 DOI: 10.1073/pnas.69.11.3278] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The (13)C-resonances of the 2',6'-ring carbon atoms of both tyrosyl residues of Clostridium acidi-urici ferredoxin are shifted downfield in the oxidized and reduced protein relative to these resonance positions in free tyrosine. These results show that both tyrosyl residues in the oxidized and reduced protein are in magnetically equivalent environments, and suggest that both tyrosyl residues are close to the two iron-sulfur clusters in the reduced and oxidized proteins and that each cluster is equally accessible to one reducing electron.
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