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Fu M, Hartmann R, Braun J, Andreev S, Pietsch T, Scheer E. Modulated critical currents of spin-transfer torque-induced resistance changes in NiCu/Cu multilayered nanowires. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:360-366. [PMID: 38590428 PMCID: PMC10999983 DOI: 10.3762/bjnano.15.32] [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: 01/09/2024] [Accepted: 03/14/2024] [Indexed: 04/10/2024]
Abstract
We present a novel method combining anodic aluminum oxide template synthesis and nanolithography to selectively deposit vertically patterned magnetic nanowires on a Si substrate. With this approach we fabricated three-dimensional nanowire-based spin valve devices without the need of complex etching processes or additional spacer coating. Through this method, we successfully obtained NiCu/Cu multilayered nanowire arrays with a controlled sequence along the long axis of the nanowires. Both magnetic switching and excitation phenomena driven by spin-polarized currents were clearly demonstrated in our NiCu/Cu multilayered nanowires. Moreover, the critical currents for switching and excitation were observed to be modulated in an oscillatory manner by the magnetic field in the nanowire-based devices. We present a toy model to qualitatively explain these observations.
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Affiliation(s)
- Mengqi Fu
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Roman Hartmann
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Julian Braun
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Sergej Andreev
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Torsten Pietsch
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Elke Scheer
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
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2
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Marqués-Marchán J, Fernandez-Roldan JA, Bran C, Puttock R, Barton C, Moreno JA, Kosel J, Vazquez M, Kazakova O, Chubykalo-Fesenko O, Asenjo A. Distinguishing Local Demagnetization Contribution to the Magnetization Process in Multisegmented Nanowires. NANOMATERIALS 2022; 12:nano12121968. [PMID: 35745306 PMCID: PMC9229024 DOI: 10.3390/nano12121968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/03/2022] [Accepted: 06/05/2022] [Indexed: 01/16/2023]
Abstract
Cylindrical magnetic nanowires are promising materials that have the potential to be used in a wide range of applications. The versatility of these nanostructures is based on the tunability of their magnetic properties, which is achieved by appropriately selecting their composition and morphology. In addition, stochastic behavior has attracted attention in the development of neuromorphic devices relying on probabilistic magnetization switching. Here, we present a study of the magnetization reversal process in multisegmented CoNi/Cu nanowires. Nonstandard 2D magnetic maps, recorded under an in-plane magnetic field, produce datasets that correlate with magnetoresistance measurements and micromagnetic simulations. From this process, the contribution of the individual segments to the demagnetization process can be distinguished. The results show that the magnetization reversal in these nanowires does not occur through a single Barkhausen jump, but rather by multistep switching, as individual CoNi segments in the NW undergo a magnetization reversal. The existence of vortex states is confirmed by their footprint in the magnetoresistance and 2D MFM maps. In addition, the stochasticity of the magnetization reversal is analysed. On the one hand, we observe different switching fields among the segments due to a slight variation in geometrical parameters or magnetic anisotropy. On the other hand, the stochasticity is observed in a series of repetitions of the magnetization reversal processes for the same NW under the same conditions.
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Affiliation(s)
- Jorge Marqués-Marchán
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.M.-M.); (C.B.); (M.V.); (O.C.-F.)
| | - Jose Angel Fernandez-Roldan
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany;
| | - Cristina Bran
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.M.-M.); (C.B.); (M.V.); (O.C.-F.)
| | - Robert Puttock
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; (R.P.); (C.B.); (O.K.)
- Department of Physics, Royal Holloway University of London, Egham TW20 0EX, UK
| | - Craig Barton
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; (R.P.); (C.B.); (O.K.)
| | - Julián A. Moreno
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;
| | - Jürgen Kosel
- Computer Electrical and Mathematical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;
- Silicon Austria Labs, Sensor Systems Division, A-9524 Villach, Austria
| | - Manuel Vazquez
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.M.-M.); (C.B.); (M.V.); (O.C.-F.)
| | - Olga Kazakova
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; (R.P.); (C.B.); (O.K.)
| | - Oksana Chubykalo-Fesenko
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.M.-M.); (C.B.); (M.V.); (O.C.-F.)
| | - Agustina Asenjo
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain; (J.M.-M.); (C.B.); (M.V.); (O.C.-F.)
- Correspondence:
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3
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Caspani S, Moraes S, Navas D, Proenca MP, Magalhães R, Nunes C, Araújo JP, Sousa CT. The Magnetic Properties of Fe/Cu Multilayered Nanowires: The Role of the Number of Fe Layers and Their Thickness. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2729. [PMID: 34685176 PMCID: PMC8538472 DOI: 10.3390/nano11102729] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/04/2021] [Accepted: 10/12/2021] [Indexed: 12/22/2022]
Abstract
Multi-segmented bilayered Fe/Cu nanowires have been fabricated through the electrodeposition in porous anodic alumina membranes. We have assessed, with the support of micromagnetic simulations, the dependence of fabricated nanostructures' magnetic properties either on the number of Fe/Cu bilayers or on the length of the magnetic layers, by fixing both the nonmagnetic segment length and the wire diameter. The magnetic reversal, in the segmented Fe nanowires (NWs) with a 300 nm length, occurs through the nucleation and propagation of a vortex domain wall (V-DW) from the extremities of each segment. By increasing the number of bilayers, the coercive field progressively increases due to the small magnetostatic coupling between Fe segments, but the coercivity found in an Fe continuous nanowire is not reached, since the interactions between layers is limited by the Cu separation. On the other hand, Fe segments 30 nm in length have exhibited a vortex configuration, with around 60% of the magnetization pointing parallel to the wires' long axis, which is equivalent to an isolated Fe nanodisc. By increasing the Fe segment length, a magnetic reversal occurred through the nucleation and propagation of a V-DW from the extremities of each segment, similar to what happens in a long cylindrical Fe nanowire. The particular case of the Fe/Cu bilayered nanowires with Fe segments 20 nm in length revealed a magnetization oriented in opposite directions, forming a synthetic antiferromagnetic system with coercivity and remanence values close to zero.
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Affiliation(s)
- Sofia Caspani
- IFIMUP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal; (S.C.); (S.M.); (M.P.P.); (R.M.); (J.P.A.)
| | - Suellen Moraes
- IFIMUP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal; (S.C.); (S.M.); (M.P.P.); (R.M.); (J.P.A.)
| | - David Navas
- ICMM-CSIC-Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - Mariana P. Proenca
- IFIMUP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal; (S.C.); (S.M.); (M.P.P.); (R.M.); (J.P.A.)
- ISOM and Dpto. Electrónica Física, Universidad Politécnica de Madrid, Avda. Complutense 30, 28040 Madrid, Spain
| | - Ricardo Magalhães
- IFIMUP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal; (S.C.); (S.M.); (M.P.P.); (R.M.); (J.P.A.)
| | - Cláudia Nunes
- LAQV, REQUIMTE, Faculty of Pharmacy of Porto University, 4050-313 Porto, Portugal;
| | - João Pedro Araújo
- IFIMUP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal; (S.C.); (S.M.); (M.P.P.); (R.M.); (J.P.A.)
| | - Célia T. Sousa
- IFIMUP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal; (S.C.); (S.M.); (M.P.P.); (R.M.); (J.P.A.)
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Tishkevich D, Vorobjova A, Shimanovich D, Kaniukov E, Kozlovskiy A, Zdorovets M, Vinnik D, Turutin A, Kubasov I, Kislyuk A, Dong M, Sayyed MI, Zubar T, Trukhanov A. Magnetic Properties of the Densely Packed Ultra-Long Ni Nanowires Encapsulated in Alumina Membrane. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:1775. [PMID: 34361161 PMCID: PMC8308109 DOI: 10.3390/nano11071775] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 12/02/2022]
Abstract
High-quality and compact arrays of Ni nanowires with a high ratio (up to 700) were obtained by DC electrochemical deposition into porous anodic alumina membranes with a distance between pores equal to 105 nm. The nanowire arrays were examined using scanning electron microscopy, X-ray diffraction analysis and vibration magnetometry at 300 K and 4.2 K. Microscopic and X-ray diffraction results showed that Ni nanowires are homogeneous, with smooth walls and mostly single-crystalline materials with a 220-oriented growth direction. The magnetic properties of the samples (coercivity and squareness) depend more on the length of the nanowires and the packing factor (the volume fraction of the nanowires in the membrane). It is shown that the dipolar interaction changes the demagnetizing field during a reversal magnetization of the Ni nanowires, and the general effective field of magnetostatic uniaxial shape anisotropy. The effect of magnetostatic interaction between ultra-long nanowires (with an aspect ratio of >500) in samples with a packing factor of ≥37% leads to a reversal magnetization state, in which a "curling"-type model of nanowire behavior is realized.
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Affiliation(s)
- Daria Tishkevich
- Laboratory of Magnetic Films Physics, Scientific-Practical Materials Research Centre of National Academy of Sciences of Belarus, 220072 Minsk, Belarus;
- Laboratory of Single Crystal Growth, South Ural State University, 454080 Chelyabinsk, Russia;
| | - Alla Vorobjova
- Department of Micro and Nanoelectronics, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus; (A.V.); (D.S.)
| | - Dmitry Shimanovich
- Department of Micro and Nanoelectronics, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus; (A.V.); (D.S.)
| | - Egor Kaniukov
- Department of Technology of Electronic Materials, Department of Materials Science of Semiconductors and Dielectrics, National University of Science and Technology, «MISIS», 119049 Moscow, Russia; (E.K.); (A.T.); (I.K.); (A.K.)
| | - Artem Kozlovskiy
- Engineering Profile Laboratory, L.N. Gumilyov Eurasian National University, Nur-Sultan 010000, Kazakhstan; (A.K.); (M.Z.)
- Laboratory of Solid State Physics, Institute of Nuclear Physics, Almaty 050032, Kazakhstan
| | - Maxim Zdorovets
- Engineering Profile Laboratory, L.N. Gumilyov Eurasian National University, Nur-Sultan 010000, Kazakhstan; (A.K.); (M.Z.)
- Laboratory of Solid State Physics, Institute of Nuclear Physics, Almaty 050032, Kazakhstan
- Department of Intelligent Information Technologies, Ural Federal University Named after the First President of Russia B.N. Yeltsin, 620075 Yekaterinburg, Russia
| | - Denis Vinnik
- Laboratory of Single Crystal Growth, South Ural State University, 454080 Chelyabinsk, Russia;
| | - Andrei Turutin
- Department of Technology of Electronic Materials, Department of Materials Science of Semiconductors and Dielectrics, National University of Science and Technology, «MISIS», 119049 Moscow, Russia; (E.K.); (A.T.); (I.K.); (A.K.)
- Department of Physics and I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Ilya Kubasov
- Department of Technology of Electronic Materials, Department of Materials Science of Semiconductors and Dielectrics, National University of Science and Technology, «MISIS», 119049 Moscow, Russia; (E.K.); (A.T.); (I.K.); (A.K.)
| | - Alexander Kislyuk
- Department of Technology of Electronic Materials, Department of Materials Science of Semiconductors and Dielectrics, National University of Science and Technology, «MISIS», 119049 Moscow, Russia; (E.K.); (A.T.); (I.K.); (A.K.)
| | - Mengge Dong
- Department of Resource and Environment, Northeastern University, Shenyang 110819, China;
| | - M. I. Sayyed
- Department of Physics, Faculty of Science, Isra University, Amman 11622, Jordan;
- Department of Nuclear Medicine Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman bin Faisal University (IAU), Dammam 31441, Saudi Arabia
| | - Tatiana Zubar
- Laboratory of Magnetic Films Physics, Scientific-Practical Materials Research Centre of National Academy of Sciences of Belarus, 220072 Minsk, Belarus;
- Laboratory of Single Crystal Growth, South Ural State University, 454080 Chelyabinsk, Russia;
| | - Alex Trukhanov
- Laboratory of Magnetic Films Physics, Scientific-Practical Materials Research Centre of National Academy of Sciences of Belarus, 220072 Minsk, Belarus;
- Laboratory of Single Crystal Growth, South Ural State University, 454080 Chelyabinsk, Russia;
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Magnetic reversal modes in cylindrical nanostructures: from disks to wires. Sci Rep 2021; 11:10100. [PMID: 33980937 PMCID: PMC8114916 DOI: 10.1038/s41598-021-89474-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/27/2021] [Indexed: 11/08/2022] Open
Abstract
Cylindrical magnetic nanowires are key elements of fast-recording and high-density 3D-storage devices. The accurate tuning of the magnetization processes at the nanoscale is crucial for the development of future nano-devices. Here, we analyzed the magnetization of Ni nanostructures with 15-100 nm in diameter and 12-230 nm in length and compared our results with experimental data for periodic arrays. Our modelling led to a phase diagram of the reversal modes where the presence of a critical diameter (d ≈ 30 nm) triggered the type of domain wall (DW) formed (transverse or vortex); while a critical length (L ≈ 100 nm) determined the number of DWs nucleated. Moreover, vortex-DWs originated from 3D skyrmion tubes, reported as one of the best configurations for storage devices. By increasing the diameter and aspect-ratio of nanowires with L > 100 nm, three reversal modes were observed: simultaneous propagation of two vortex-DWs; propagation of one vortex-DW; or spiral rotation of both DWs through "corkscrew" mechanism. Only for very low aspect-ratios (nanodisks), no skyrmion tubes were observed and reversal occurred by spiral rotation of one vortex-DW. The broad range of nanostructures studied allowed the creation of a complete phase diagram, highly important for future choice of nanoscaled dimensions in the development of novel nano-devices.
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Rial J, Proenca MP. A Novel Design of a 3D Racetrack Memory Based on Functional Segments in Cylindrical Nanowire Arrays. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E2403. [PMID: 33271869 PMCID: PMC7761019 DOI: 10.3390/nano10122403] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 11/16/2022]
Abstract
A racetrack memory is a device where the information is stored as magnetic domains (bits) along a nanowire (track). To read and record the information, the bits are moved along the track by current pulses until they reach the reading/writing heads. In particular, 3D racetrack memory devices use arrays of vertically aligned wires (tracks), thus enhancing storage density. In this work, we propose a novel 3D racetrack memory configuration based on functional segments inside cylindrical nanowire arrays. The innovative idea is the integration of the writing element inside the racetrack itself, avoiding the need to implement external writing heads next to the track. The use of selective magnetic segments inside one nanowire allows the creation of writing and storage sections inside the same track, separated by chemical constraints identical to those separating the bits. Using micromagnetic simulations, our study reveals that if the writing section is composed of two segments with different coercivities, one can reverse its magnetization independently from the rest of the memory device by applying an external magnetic field. Spin-polarized current pulses then move the information bits along selected tracks, completing the writing process by pushing the new bit into the storage section of the wire. Finally, we have proven the efficacy of this system inside an array of 7 nanowires, opening the possibility to use this configuration in a 3D racetrack memory device composed of an array of thousands of nanowires produced by low-cost and high-yield template-electrodeposition methods.
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Affiliation(s)
- Javier Rial
- IFIMUP—Institute of Physics for Advanced Materials, Nanotechnology and Photonics, Department of Physics and Astronomy, Faculty of Sciences, University of Porto, Rua do Campo Alegre 678, 4169-007 Porto, Portugal
| | - Mariana P. Proenca
- IFIMUP—Institute of Physics for Advanced Materials, Nanotechnology and Photonics, Department of Physics and Astronomy, Faculty of Sciences, University of Porto, Rua do Campo Alegre 678, 4169-007 Porto, Portugal
- ISOM—Institute of Optoelectronic Systems and Microtechnology, Technical University of Madrid, Avda. Complutense 30, 28040, Madrid, Spain
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7
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Caspani S, Magalhães R, Araújo JP, Sousa CT. Magnetic Nanomaterials as Contrast Agents for MRI. MATERIALS 2020; 13:ma13112586. [PMID: 32517085 PMCID: PMC7321635 DOI: 10.3390/ma13112586] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/18/2020] [Accepted: 05/29/2020] [Indexed: 01/17/2023]
Abstract
Magnetic Resonance Imaging (MRI) is a powerful, noninvasive and nondestructive technique, capable of providing three-dimensional (3D) images of living organisms. The use of magnetic contrast agents has allowed clinical researchers and analysts to significantly increase the sensitivity and specificity of MRI, since these agents change the intrinsic properties of the tissues within a living organism, increasing the information present in the images. Advances in nanotechnology and materials science, as well as the research of new magnetic effects, have been the driving forces that are propelling forward the use of magnetic nanostructures as promising alternatives to commercial contrast agents used in MRI. This review discusses the principles associated with the use of contrast agents in MRI, as well as the most recent reports focused on nanostructured contrast agents. The potential applications of gadolinium- (Gd) and manganese- (Mn) based nanomaterials and iron oxide nanoparticles in this imaging technique are discussed as well, from their magnetic behavior to the commonly used materials and nanoarchitectures. Additionally, recent efforts to develop new types of contrast agents based on synthetic antiferromagnetic and high aspect ratio nanostructures are also addressed. Furthermore, the application of these materials in theragnosis, either as contrast agents and controlled drug release systems, contrast agents and thermal therapy materials or contrast agents and radiosensitizers, is also presented.
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Ghafouri A, Ramazani A, Montazer AH. 3D interacting magnetic multilayered nanowire arrays: the emergence and evolution of new first-order reversal curve features. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:155801. [PMID: 31846942 DOI: 10.1088/1361-648x/ab62ba] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The crucial role of magnetostatic interactions in tuning properties of storage devices based on magnetic nanowires (NWs) has recently been highlighted by advanced characterization techniques including the first-order reversal curve (FORC) analysis, evaluating physical entities constituting conventional 2D NW systems. Herein, FORC diagrams of ferromagnetic (FM)/non-magnetic (NM) multilayered NW arrays are simulated using Monte Carlo calculations, involving magnetostatic interactions between segments in 3D space. The FM length is constant to 6 µm whereas the NM length (L NM) varies from 10 to 300 nm, significantly influencing interwire and intrasegment interactions of neighboring NWs and coupled segments along the NW length. Intriguingly, this is accompanied with the emergence of two new FORC diagram features in addition to the typical demagnetizing-type feature, indicating complex behavior of the 3D interacting NWs with the same anisotropy field for each FM segment. The FORC coercivity of the emerging features is tracked individually, presenting evolution as a function of L NM. Our results also evidence an increase in interwire and intrasegment interactions when increasing NW diameter, being in accordance with total magnetostatic energy calculations.
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Affiliation(s)
- A Ghafouri
- Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan 87317-51167, Iran
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9
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Rose JC, Fölster M, Kivilip L, Gerardo-Nava JL, Jaekel EE, Gehlen DB, Rohlfs W, De Laporte L. Predicting the orientation of magnetic microgel rods for soft anisotropic biomimetic hydrogels. Polym Chem 2020. [DOI: 10.1039/c9py01008d] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Predicting the orientation rate of rod-shaped magnetic microgels to induce unidirectional regeneration of complex and sensitive tissues.
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Affiliation(s)
- Jonas C. Rose
- DWI – Leibniz-Institute for Interactive Materials
- Aachen
- Germany
| | - Maaike Fölster
- DWI – Leibniz-Institute for Interactive Materials
- Aachen
- Germany
| | - Lukas Kivilip
- RWTH Aachen University
- Institute of Heat and Mass Transfer
- Aachen
- Germany
| | | | | | - David B. Gehlen
- DWI – Leibniz-Institute for Interactive Materials
- Aachen
- Germany
| | - Wilko Rohlfs
- RWTH Aachen University
- Institute of Heat and Mass Transfer
- Aachen
- Germany
| | - Laura De Laporte
- DWI – Leibniz-Institute for Interactive Materials
- Aachen
- Germany
- RWTH Aachen University
- Institute for Technical and Macromolecular Chemistry
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10
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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, SWITZERLAND) 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] [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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Sergelius P, Lee JH, Fruchart O, Salem MS, Allende S, Escobar RA, Gooth J, Zierold R, Toussaint JC, Schneider S, Pohl D, Rellinghaus B, Martin S, Garcia J, Reith H, Spende A, Toimil-Molares ME, Altbir D, Cowburn R, Görlitz D, Nielsch K. Intra-wire coupling in segmented Ni/Cu nanowires deposited by electrodeposition. NANOTECHNOLOGY 2017; 28:065709. [PMID: 28067207 DOI: 10.1088/1361-6528/aa5118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Segmented magnetic nanowires are a promising route for the development of three dimensional data storage techniques. Such devices require a control of the coercive field and the coupling mechanisms between individual magnetic elements. In our study, we investigate electrodeposited nanomagnets within host templates using vibrating sample magnetometry and observe a strong dependence between nanowire length and coercive field (25 nm-5 μm) and diameter (25-45 nm). A transition from a magnetization reversal through coherent rotation to domain wall propagation is observed at an aspect ratio of approximately 2. Our results are further reinforced via micromagnetic simulations and angle dependent hysteresis loops. The found behavior is exploited to create nanowires consisting of a fixed and a free segment in a spin-valve like structure. The wires are released from the membrane and electrically contacted, displaying a giant magnetoresistance effect that is attributed to individual switching of the coupled nanomagnets. We develop a simple analytical model to describe the observed switching phenomena and to predict stable and unstable regimes in coupled nanomagnets of certain geometries.
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Affiliation(s)
- Philip Sergelius
- Institute of Nanostructure and Solid-State Physics, Universität Hamburg, D-20355 Hamburg, Germany
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