1
|
Beeson WB, Bista D, Zhang H, Krylyuk S, Davydov AV, Yin G, Liu K. Single-Phase L1 0-Ordered High Entropy Thin Films with High Magnetic Anisotropy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2308574. [PMID: 38943261 DOI: 10.1002/advs.202308574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 05/13/2024] [Indexed: 07/01/2024]
Abstract
The vast high entropy alloy (HEA) composition space is promising for discovery of new material phases with unique properties. This study explores the potential to achieve rare-earth-free high magnetic anisotropy materials in single-phase HEA thin films. Thin films of FeCoNiMnCu sputtered on thermally oxidized Si/SiO2 substrates at room temperature are magnetically soft, with a coercivity on the order of 10 Oe. After post-deposition rapid thermal annealing (RTA), the films exhibit a single face-centered-cubic phase, with an almost 40-fold increase in coercivity. Inclusion of 50 at.% Pt in the film leads to ordering of a single L10 high entropy intermetallic phase after RTA, along with high magnetic anisotropy and 3 orders of magnitude coercivity increase. These results demonstrate a promising HEA approach to achieve high magnetic anisotropy materials using RTA.
Collapse
Affiliation(s)
- Willie B Beeson
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Dinesh Bista
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Huairuo Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
- Theiss Research, Inc., La Jolla, CA, 92037, USA
| | - Sergiy Krylyuk
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Albert V Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Gen Yin
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| |
Collapse
|
2
|
Cabanas AM, Pérez del Real R, Laroze D, Vázquez M. First-Order Reversal Curves of Sets of Bistable Magnetostrictive Microwires. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16062131. [PMID: 36984011 PMCID: PMC10058406 DOI: 10.3390/ma16062131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/05/2023] [Accepted: 02/08/2023] [Indexed: 05/27/2023]
Abstract
Amorphous microwires have attracted substantial attention in the past decade because of their useful technological applications. Their bistable magnetic response is determined by positive or negative magnetostriction, respectively. First-order reversal curves (FORC) are a powerful tool for analyzing the magnetization reversal processes of many-body ferromagnetic systems that are essential for a deeper understanding of those applications. After theoretical considerations about magnetostatic interactions among microwires, this work introduces a systematic experimental study and analysis of the FORC diagrams for magnetostrictive microwires exhibiting an individually bistable hysteresis loop, from a single microwire to sets of an increasing number of coupled microwires, the latter considered as an intermediate case to the standard many-body problem. We performed the study for sets of quasi-identical and different hysteretic microwires where we obtained the coercivity Hc and interaction Hu fields. In the cases with relevant magnetostatic interactions, FORC analysis supplies deeper information than standard hysteresis loops since the intrinsic fluctuations of the switching field generate a complex response. For sets of microwires with very different coercivity, the coercivity distributions of the individual microwires characterize the FORC diagram.
Collapse
Affiliation(s)
- Ana María Cabanas
- Departamento de Física, FACI Universidad de Tarapacá, Arica 1010069, Chile
| | | | - David Laroze
- Instituto de Alta Investigación, CEDENNA, Universidad de Tarapacá, Casilla 7D, Arica 1010069, Chile
| | - Manuel Vázquez
- Instituto de Ciencia de Materiales, CSIC, 28049 Madrid, Spain
| |
Collapse
|
3
|
Bhattacharya D, Chen Z, Jensen CJ, Liu C, Burks EC, Gilbert DA, Zhang X, Yin G, Liu K. 3D Interconnected Magnetic Nanowire Networks as Potential Integrated Multistate Memristors. NANO LETTERS 2022; 22:10010-10017. [PMID: 36480011 DOI: 10.1021/acs.nanolett.2c03616] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Interconnected magnetic nanowire (NW) networks offer a promising platform for three-dimensional (3D) information storage and integrated neuromorphic computing. Here we report discrete propagation of magnetic states in interconnected Co nanowire networks driven by magnetic field and current, manifested in distinct magnetoresistance (MR) features. In these networks, when only a few interconnected NWs were measured, multiple MR kinks and local minima were observed, including a significant minimum at a positive field during the descending field sweep. Micromagnetic simulations showed that this unusual feature was due to domain wall (DW) pinning at the NW intersections, which was confirmed by off-axis electron holography imaging. In a complex network with many intersections, sequential switching of nanowire sections separated by interconnects was observed, along with stochastic characteristics. The pinning/depinning of the DWs can be further controlled by the driving current density. These results illustrate the promise of such interconnected networks as integrated multistate memristors.
Collapse
Affiliation(s)
| | - Zhijie Chen
- Physics Department, Georgetown University, Washington, D.C.20057, United States
| | | | - Chen Liu
- Physical Science and Engineering Division, King Abdullah University of Science & Technology, Thuwal23955-6900, Saudi Arabia
| | - Edward C Burks
- Physics Department, University of California, Davis, California95618, United States
| | - Dustin A Gilbert
- Department of Materials Science and Engineering, and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science & Technology, Thuwal23955-6900, Saudi Arabia
| | - Gen Yin
- Physics Department, Georgetown University, Washington, D.C.20057, United States
| | - Kai Liu
- Physics Department, Georgetown University, Washington, D.C.20057, United States
| |
Collapse
|
4
|
Effect of Piezoelectric BaTiO 3 Filler on Mechanical and Magnetoelectric Properties of Zn 0.25Co 0.75Fe 2O 4/PVDF-TrFE Composites. Polymers (Basel) 2022; 14:polym14224807. [PMID: 36432934 PMCID: PMC9695481 DOI: 10.3390/polym14224807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
Polymer-based multiferroics, combining magnetic and piezoelectric properties, are studied experimentally-from synthesis to multi-parameter characterization-in view of their prospects for fabricating biocompatible scaffolds. The main advantage of these systems is facile generation of mechanical deformations and electric signals in response to external magnetic fields. Herein, we address the composites based on PVDF-TrFE polymer matrices filled with a combination of piezoelectric (BaTiO3, BTO) and/or ferrimagnetic (Zn0.25Co0.75Fe2O4, ZCFO) particles. It is shown that the presence of BTO micron-size particles favors stripe-type structuring of the ZCFO filler and enhances the magnetoelectric response of the sample up to 18.6 mV/(cm∙Oe). Besides that, the admixing of BTO particles is crucial because the mechanical properties of the composite filled with only ZCFO is much less efficient in transforming magnetic excitations into the mechanical and electric responses. Attention is focused on the local surfacial mechanical properties since those, to a great extent, determine the fate of stem cells cultivated on these surfaces. The nano-indentation tests are accomplished with the aid of scanning probe microscopy technique. With their proven suitable mechanical properties, a high level of magnetoelectric conversion and also biocompatibility, the composites of the considered type are enticing as the materials for multiferroic-based polymer scaffolds.
Collapse
|
5
|
Kouhpanji MRZ, Zhang Y, Um J, Srinivasan K, Sharma A, Shore D, Gao Z, Chen Y, Harpel A, Porshokouh ZN, Gage TE, Dragos-Pinzaru O, Tabakovic I, Visscher PB, Bischof J, Modiano JF, Franklin R, Stadler BJH. Bioapplications of Magnetic Nanowires: Barcodes, Biocomposites, Heaters. IEEE TRANSACTIONS ON MAGNETICS 2022; 58:5200406. [PMID: 36864851 PMCID: PMC9976993 DOI: 10.1109/tmag.2022.3151608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Magnetic nanowires (MNWs) can have their moments reversed via several mechanisms that are controlled using the composition, length, diameter, and density of nanowires in arrays as-synthesized or as individual nanoparticles in assays or gels. This tailoring of magnetic reversal leads to unique properties that can be used as a signature for reading out the type of MNW for applications as nano-barcodes. When synthesized inside track-etched polycarbonate membranes, the resulting MNW-embedded membranes can be used as biocompatible bandaids for detection without contact or optical sighting. When etched out of the growth template, free-floating MNWs are internalized by cells at 37 °C such that cells and/or exosomes can be collected and detected. In applications of cryopreservation, MNWs can be suspended in cryopreservation agents (CPAs) for injection into the blood vessels of tissues and organs as they are vitrified to -200 °C. Using an alternating magnetic field, the MNWs can then be nanowarmed rapidly to prevent crystallization and uniformly to prevent cracking of specimens, for example, as grafts or transplants. This invited paper is a review of recent progress in the specific bioapplications of MNWs to barcodes, biocomposites, and nanowarmers.
Collapse
Affiliation(s)
| | - Yali Zhang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Joseph Um
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Kartihik Srinivasan
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Anirudh Sharma
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Daniel Shore
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 USA
| | - Zhe Gao
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Yicong Chen
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 USA
| | - Allison Harpel
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 USA
| | - Zohreh Nemati Porshokouh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Thomas E Gage
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 USA
| | - Oana Dragos-Pinzaru
- National Institute of Research and Development for Technical Physics, 700050 Iasi, Romania
| | - Ibro Tabakovic
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - P B Visscher
- Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL 35401 USA
| | - John Bischof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Jaime F Modiano
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Falcon Heights, MN 55108 USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455 USA
| | - Rhonda Franklin
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Bethanie J H Stadler
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455 USA
| |
Collapse
|
6
|
FORC-Diagram Analysis for a Step-like Magnetization Reversal in Nanopatterned Stripe Array. MATERIALS 2021; 14:ma14247523. [PMID: 34947121 PMCID: PMC8715669 DOI: 10.3390/ma14247523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/02/2021] [Accepted: 12/05/2021] [Indexed: 11/16/2022]
Abstract
The fabrication approach of a magnonic crystal with a step-like hysteresis behavior based on a uniform non-monotonous iron layer made by shadow deposition on a preconfigured substrate is reported. The origin of the step-like hysteresis loop behavior is studied with local and integral magnetometry methods, including First-Order Reversal Curves (FORC) diagram analysis, accompanied with magnetic microstructure dynamics measurements. The results are validated with macroscopic magnetic properties and micromagnetic simulations using the intrinsic switching field distribution model. The proposed fabrication method can be used to produce magnonic structures with the controllable hysteresis plateau region's field position and width that can be used to control the magnonic crystal's band structure by changing of an external magnetic field.
Collapse
|
7
|
Coercivity Mechanism and Magnetization Reversal in Anisotropic Ce-(Y)-Pr-Fe-B Films. MATERIALS 2021; 14:ma14164680. [PMID: 34443202 PMCID: PMC8399603 DOI: 10.3390/ma14164680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/30/2021] [Accepted: 08/05/2021] [Indexed: 11/28/2022]
Abstract
In this study, the magnetic properties, coercivity mechanism, and magnetization reversal process were investigated for Ce-(Y)-Pr-Fe-B films. After the addition of Y and subsequent heating treatment, the formations of REO (RE ≡ Ce and Pr) and REFe2 (RE ≡ rare earths) phases are inhibited, and the microstructure of Ce-Y-Pr-Fe-B film is optimized. Meanwhile, the coercivity and the squareness of the hysteresis loop are significantly improved. The coercivity mechanism of Ce-Y-Pr-Fe-B film is determined to be a mixture of nucleation and pinning mechanisms, but dominated by the nucleation mechanism. The demagnetization results show that the nucleation of reversal magnetic domains leads to irreversible reversal. Our results are helpful to understand the coercivity mechanism and magnetization reversal of permanent magnetic films with multi-main phases.
Collapse
|
8
|
Zamani Kouhpanji MR, Stadler BJH. Magnetic Nanowires for Nanobarcoding and Beyond. SENSORS (BASEL, SWITZERLAND) 2021; 21:4573. [PMID: 34283095 PMCID: PMC8271806 DOI: 10.3390/s21134573] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/26/2021] [Accepted: 07/01/2021] [Indexed: 12/15/2022]
Abstract
Multifunctional magnetic nanowires (MNWs) have been studied intensively over the last decades, in diverse applications. Numerous MNW-based systems have been introduced, initially for fundamental studies and later for sensing applications such as biolabeling and nanobarcoding. Remote sensing of MNWs for authentication and/or anti-counterfeiting is not only limited to engineering their properties, but also requires reliable sensing and decoding platforms. We review the latest progress in designing MNWs that have been, and are being, introduced as nanobarcodes, along with the pros and cons of the proposed sensing and decoding methods. Based on our review, we determine fundamental challenges and suggest future directions for research that will unleash the full potential of MNWs for nanobarcoding applications.
Collapse
Affiliation(s)
- Mohammad Reza Zamani Kouhpanji
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Bethanie J. H. Stadler
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA;
| |
Collapse
|
9
|
Gilbert DA, Murray PD, De Rojas J, Dumas RK, Davies JE, Liu K. Reconstructing phase-resolved hysteresis loops from first-order reversal curves. Sci Rep 2021; 11:4018. [PMID: 33597639 PMCID: PMC7889904 DOI: 10.1038/s41598-021-83349-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/11/2021] [Indexed: 11/09/2022] Open
Abstract
The first order reversal curve (FORC) method is a magnetometry based technique used to capture nanoscale magnetic phase separation and interactions with macroscopic measurements using minor hysteresis loop analysis. This makes the FORC technique a powerful tool in the analysis of complex systems which cannot be effectively probed using localized techniques. However, recovering quantitative details about the identified phases which can be compared to traditionally measured metrics remains an enigmatic challenge. We demonstrate a technique to reconstruct phase-resolved magnetic hysteresis loops by selectively integrating the measured FORC distribution. From these minor loops, the traditional metrics-including the coercivity and saturation field, and the remanent and saturation magnetization-can be determined. In order to perform this analysis, special consideration must be paid to the accurate quantitative management of the so-called reversible features. This technique is demonstrated on three representative materials systems, high anisotropy FeCuPt thin-films, Fe nanodots, and SmCo/Fe exchange spring magnet films, and shows excellent agreement with the direct measured major loop, as well as the phase separated loops.
Collapse
Affiliation(s)
- Dustin A Gilbert
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37919, USA.
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37919, USA.
| | - Peyton D Murray
- Physics Department, University of California, Davis, CA, 95616, USA
| | - Julius De Rojas
- Physics Department, University of California, Davis, CA, 95616, USA
| | | | - Joseph E Davies
- Advanced Technology Group, NVE Corp, Eden Prairie, MN, 55344, USA
| | - Kai Liu
- Physics Department, University of California, Davis, CA, 95616, USA
- Department of Physics, Georgetown University, Washington, DC, 20057, USA
| |
Collapse
|
10
|
Burks EC, Gilbert DA, Murray PD, Flores C, Felter TE, Charnvanichborikarn S, Kucheyev SO, Colvin JD, Yin G, Liu K. 3D Nanomagnetism in Low Density Interconnected Nanowire Networks. NANO LETTERS 2021; 21:716-722. [PMID: 33301687 DOI: 10.1021/acs.nanolett.0c04366] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Free-standing, interconnected metallic nanowire networks with densities as low as 40 mg/cm3 have been achieved over centimeter-scale areas, using electrodeposition into polycarbonate membranes that have been ion-tracked at multiple angles. Networks of interconnected magnetic nanowires further provide an exciting platform to explore 3-dimensional nanomagnetism, where their structure, topology, and frustration may be used as additional degrees of freedom to tailor the materials properties. New magnetization reversal mechanisms in cobalt networks are captured by the first-order reversal curve method, which demonstrate the evolution from strong demagnetizing dipolar interactions to intersection-mediated domain wall pinning and propagation, and eventually to shape-anisotropy dominated magnetization reversal. These findings open up new possibilities for 3-dimensional integrated magnetic devices for memory, complex computation, and neuromorphics.
Collapse
Affiliation(s)
- Edward C Burks
- Physics Department, University of California, Davis, California 95618, United States
| | - Dustin A Gilbert
- Physics Department, University of California, Davis, California 95618, United States
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Peyton D Murray
- Physics Department, University of California, Davis, California 95618, United States
| | - Chad Flores
- Physics Department, University of California, Davis, California 95618, United States
| | - Thomas E Felter
- Sandia National Laboratories, Livermore, California 94551, United States
| | | | - Sergei O Kucheyev
- Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Jeffrey D Colvin
- Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Gen Yin
- Physics Department, Georgetown University, Washington, D.C. 20057, United States
| | - Kai Liu
- Physics Department, University of California, Davis, California 95618, United States
- Physics Department, Georgetown University, Washington, D.C. 20057, United States
| |
Collapse
|
11
|
Relation of the average interaction field with the coercive and interaction field distributions in First order reversal curve diagrams of nanowire arrays. Sci Rep 2020; 10:21396. [PMID: 33288826 PMCID: PMC7721885 DOI: 10.1038/s41598-020-78279-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 11/17/2020] [Indexed: 11/17/2022] Open
Abstract
First-order reversal curve diagrams, or FORC diagrams, have been studied to determine if the widths of their distributions along the interaction and coercivity axes can be related to the mean-field magnetization dependent interaction field (MDIF). Arrays of nanowires with diameters ranging from 18 up to 100 nm and packing fractions varying from 0.4 to 12% have been analyzed. The mean-field MDIF has been measured using the remanence curves and used as a measuring scale on the FORC diagrams. Based on these measurements, the full width of the interaction field distribution and the full width at half maximum (FWHM) of the FORC distribution profile along the interaction field direction are shown to be proportional to the MDIF, and the relation between them is found. Moreover, by interpreting the full width of the coercive field distribution in terms of the dipolar induced shearing, a simple relation is found between the width of this distribution and the MDIF. Furthermore, we show that the width of the FORC distribution along the coercive field axis is equal to the width of the switching field distribution obtained by the derivation of the DC remanence curve. This was further verified with the switching field distribution determined using in-field magnetic force microscopy (MFM) for very low density nanowires. The results are further supported by the good agreement found between the experiments and the values calculated using the mean-field model, which provides analytical expressions for both FORC distributions.
Collapse
|
12
|
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.
Collapse
Affiliation(s)
- A Ghafouri
- Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan 87317-51167, Iran
| | | | | |
Collapse
|
13
|
Zamani Kouhpanji MR, Stadler BJH. Beyond the qualitative description of complex magnetic nanoparticle arrays using FORC measurement. NANO EXPRESS 2020. [DOI: 10.1088/2632-959x/ab844d] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
14
|
Bodale I, Stancu A. Reversible and Irreversible Processes in Drying and Wetting of Soil. MATERIALS 2019; 13:ma13010135. [PMID: 31905633 PMCID: PMC6981664 DOI: 10.3390/ma13010135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 11/16/2022]
Abstract
In this article, we provide a detailed description of a modeling technique for the capillary hysteresis in a soil-like porous material based on a Generalized Preisach Model. The identification of the reversible and irreversible Preisach distributions was performed with the first-order reversal curve (FORC) diagram technique, which is very popular now in magnetism and in other areas of science to give a fingerprint of the studied system. A special attention was given to the evaluation of the reversible component. In this case, we used a set of data published in 1965 by Morrow and Harris which has been used as a reference by many other researchers since. The advantage of this approach is that the experimental FORC distributions can be described with analytical functions and easily implemented in the mentioned Preisach-type model. Our research is also focused on the development of a characterization tool for the soil using the soil-moisture hysteresis. The systematic use of scanning curves provides a (FORC) diagram linked to the physical properties of the studied soil. The agreement between the experimental data and the Preisach model using the set of parameters found through the FORC technique is really noticeable and gives a good practical option to the researchers to use a method with a strong predictive capability.
Collapse
Affiliation(s)
- Ilie Bodale
- Faculty of Horticulture, University of Agricultural Sciences and Veterinary Medicine, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania;
| | - Alexandru Stancu
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, 11 Boulevard Carol I, 700506 Iasi, Romania
- Correspondence:
| |
Collapse
|
15
|
Gilbert DA, Ramírez JG, Saerbeck T, Trastoy J, Schuller IK, Liu K, de la Venta J. Growth-Induced In-Plane Uniaxial Anisotropy in V 2O 3/Ni Films. Sci Rep 2017; 7:13471. [PMID: 29044131 PMCID: PMC5647448 DOI: 10.1038/s41598-017-12690-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/13/2017] [Indexed: 11/11/2022] Open
Abstract
We report on a strain-induced and temperature dependent uniaxial anisotropy in V2O3/Ni hybrid thin films, manifested through the interfacial strain and sample microstructure, and its consequences on the angular dependent magnetization reversal. X-ray diffraction and reciprocal space maps identify the in-plane crystalline axes of the V2O3; atomic force and scanning electron microscopy reveal oriented rips in the film microstructure. Quasi-static magnetometry and dynamic ferromagnetic resonance measurements identify a uniaxial magnetic easy axis along the rips. Comparison with films grown on sapphire without rips shows a combined contribution from strain and microstructure in the V2O3/Ni films. Magnetization reversal characteristics captured by angular-dependent first order reversal curve measurements indicate a strong domain wall pinning along the direction orthogonal to the rips, inducing an angular-dependent change in the reversal mechanism. The resultant anisotropy is tunable with temperature and is most pronounced at room temperature, which is beneficial for potential device applications.
Collapse
Affiliation(s)
- Dustin A Gilbert
- Physics Department, University of California, Davis, California, 95616, United States. .,NIST Center for Neutron Research, Gaithersburg, Maryland, 20899, United States.
| | | | - T Saerbeck
- Institut Laue-Langevin, 71 Av. Des Martyrs, CS 20156, 38042, Grenoble cedex 9, France
| | - J Trastoy
- Physics Department, University of California, San Diego, California, 92093, United States
| | - Ivan K Schuller
- Physics Department, University of California, San Diego, California, 92093, United States
| | - Kai Liu
- Physics Department, University of California, Davis, California, 95616, United States.
| | - J de la Venta
- Physics Department, Colorado State University, Fort Collins, Colorado, 80523, United States.
| |
Collapse
|
16
|
First order reversal curves and intrinsic parameter determination for magnetic materials; limitations of hysteron-based approaches in correlated systems. Sci Rep 2017; 7:45218. [PMID: 28338056 PMCID: PMC5364551 DOI: 10.1038/srep45218] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/20/2017] [Indexed: 11/08/2022] Open
Abstract
The generic problem of extracting information on intrinsic particle properties from the whole class of interacting magnetic fine particle systems is a long standing and difficult inverse problem. As an example, the Switching Field Distribution (SFD) is an important quantity in the characterization of magnetic systems, and its determination in many technological applications, such as recording media, is especially challenging. Techniques such as the first order reversal curve (FORC) methods, were developed to extract the SFD from macroscopic measurements. However, all methods rely on separating the contributions to the measurements of the intrinsic SFD and the extrinsic effects of magnetostatic and exchange interactions. We investigate the underlying physics of the FORC method by applying it to the output predictions of a kinetic Monte-Carlo model with known input parameters. We show that the FORC method is valid only in cases of weak spatial correlation of the magnetisation and suggest a more general approach.
Collapse
|
17
|
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.
Collapse
Affiliation(s)
- Philip Sergelius
- Institute of Nanostructure and Solid-State Physics, Universität Hamburg, D-20355 Hamburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Antohe VA, Nysten E, Martínez-Huerta JM, Pereira de Sá PM, Piraux L. Annealing effects on the magnetic properties of highly-packed vertically-aligned nickel nanotubes. RSC Adv 2017. [DOI: 10.1039/c7ra01276d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hysteresis loops showing the decrease of the saturation magnetic moment (left) through a dense array of vertically-aligned Ni nanotubes after their progressive thermal conversion into hybrid ferromagnetic/antiferromagnetic Ni/NiO nanotubes (right).
Collapse
Affiliation(s)
- Vlad-Andrei Antohe
- Institute of Condensed Matter and Nanosciences (IMCN)
- Université Catholique de Louvain (UCL)
- B-1348 Louvain-la-Neuve
- Belgium
- Research and Development Center for Materials and Electronic & Optoelectronic Devices (MDEO)
| | - Emeline Nysten
- Institute of Condensed Matter and Nanosciences (IMCN)
- Université Catholique de Louvain (UCL)
- B-1348 Louvain-la-Neuve
- Belgium
| | - Juan Manuel Martínez-Huerta
- Institute of Condensed Matter and Nanosciences (IMCN)
- Université Catholique de Louvain (UCL)
- B-1348 Louvain-la-Neuve
- Belgium
| | - Pedro Miguel Pereira de Sá
- Institute of Condensed Matter and Nanosciences (IMCN)
- Université Catholique de Louvain (UCL)
- B-1348 Louvain-la-Neuve
- Belgium
| | - Luc Piraux
- Institute of Condensed Matter and Nanosciences (IMCN)
- Université Catholique de Louvain (UCL)
- B-1348 Louvain-la-Neuve
- Belgium
| |
Collapse
|
19
|
Pohlit M, Eibisch P, Akbari M, Porrati F, Huth M, Müller J. First order reversal curves (FORC) analysis of individual magnetic nanostructures using micro-Hall magnetometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:113907. [PMID: 27910450 DOI: 10.1063/1.4967940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Alongside the development of artificially created magnetic nanostructures, micro-Hall magnetometry has proven to be a versatile tool to obtain high-resolution hysteresis loop data and access dynamical properties. Here we explore the application of First Order Reversal Curves (FORC)-a technique well-established in the field of paleomagnetism for studying grain-size and interaction effects in magnetic rocks-to individual and dipolar-coupled arrays of magnetic nanostructures using micro-Hall sensors. A proof-of-principle experiment performed on a macroscopic piece of a floppy disk as a reference sample well known in the literature demonstrates that the FORC diagrams obtained by magnetic stray field measurements using home-built magnetometers are in good agreement with magnetization data obtained by a commercial vibrating sample magnetometer. We discuss in detail the FORC diagrams and their interpretation of three different representative magnetic systems, prepared by the direct-write Focused Electron Beam Induced Deposition (FEBID) technique: (1) an isolated Co-nanoisland showing a simple square-shaped hysteresis loop, (2) a more complex CoFe-alloy nanoisland exhibiting a wasp-waist-type hysteresis, and (3) a cluster of interacting Co-nanoislands. Our findings reveal that the combination of FORC and micro-Hall magnetometry is a promising tool to investigate complex magnetization reversal processes within individual or small ensembles of nanomagnets grown by FEBID or other fabrication methods. The method provides sub-μm spatial resolution and bridges the gap of FORC analysis, commonly used for studying macroscopic samples and rather large arrays, to studies of small ensembles of interacting nanoparticles with the high moment sensitivity inherent to micro-Hall magnetometry.
Collapse
Affiliation(s)
- Merlin Pohlit
- Institute of Physics, Goethe-University, Frankfurt/Main, Germany
| | - Paul Eibisch
- Institute of Physics, Goethe-University, Frankfurt/Main, Germany
| | - Maryam Akbari
- Institute of Physics, Goethe-University, Frankfurt/Main, Germany
| | - Fabrizio Porrati
- Institute of Physics, Goethe-University, Frankfurt/Main, Germany
| | - Michael Huth
- Institute of Physics, Goethe-University, Frankfurt/Main, Germany
| | - Jens Müller
- Institute of Physics, Goethe-University, Frankfurt/Main, Germany
| |
Collapse
|
20
|
Palmero EM, Béron F, Bran C, Del Real RP, Vázquez M. Magnetic interactions in compositionally modulated nanowire arrays. NANOTECHNOLOGY 2016; 27:435705. [PMID: 27658858 DOI: 10.1088/0957-4484/27/43/435705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Series of high hexagonally ordered compositionally modulated nanowire arrays, with different Cu layer and FeCoCu segment thicknesses and a constant diameter of 35 nm, were fabricated by electroplating from a single electrolytic bath into anodic aluminum oxide membranes. The objective of the study was to determine the influence of ferromagnetic (FM) segment and non-ferromagnetic (NFM) layer thickness on the magnetic properties, particularly coercivity and magnetic interactions. First-order reversal curve (FORC) measurements and simulations were performed to quantify the effect of the inter-/intra-nanowire magnetostatic interactions on the coercivity and interaction field distributions. The FORC coercivity increases for a thick NFM layer and long FM segments due to decoupling of the the FM segments and the increased shape anisotropy, respectively. On the other hand, the interaction field presents a parallel strong reduction for a thick NFM layer and thin FM segments, which is ascribed to a similar NFM/FM thickness ratio and degree of FM segment decoupling along the nanowire.
Collapse
Affiliation(s)
- Ester M Palmero
- Institute of Materials Science of Madrid, CSIC, 28049 Madrid, Spain
| | | | | | | | | |
Collapse
|
21
|
Gilbert DA, Liao JW, Kirby BJ, Winklhofer M, Lai CH, Liu K. Magnetic Yoking and Tunable Interactions in FePt-Based Hard/Soft Bilayers. Sci Rep 2016; 6:32842. [PMID: 27604428 PMCID: PMC5015099 DOI: 10.1038/srep32842] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/16/2016] [Indexed: 11/16/2022] Open
Abstract
Magnetic interactions in magnetic nanostructures are critical to nanomagnetic and spintronic explorations. Here we demonstrate an extremely sensitive magnetic yoking effect and tunable interactions in FePt based hard/soft bilayers mediated by the soft layer. Below the exchange length, a thin soft layer strongly exchange couples to the perpendicular moments of the hard layer; above the exchange length, just a few nanometers thicker, the soft layer moments turn in-plane and act to yoke the dipolar fields from the adjacent hard layer perpendicular domains. The evolution from exchange to dipolar-dominated interactions is experimentally captured by first-order reversal curves, the ΔM method, and polarized neutron reflectometry, and confirmed by micromagnetic simulations. These findings demonstrate an effective yoking approach to design and control magnetic interactions in wide varieties of magnetic nanostructures and devices.
Collapse
Affiliation(s)
- Dustin A. Gilbert
- Dept. of Physics, University of California, Davis, California 95616, USA
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - Jung-Wei Liao
- Dept. of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Brian J. Kirby
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - Michael Winklhofer
- Dept. of Earth and Environmental Sciences, Geophysics, Munich University, 80333 Germany
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
- IBU, School of Mathematics and Science, Carl von Ossietzky University, 26129, Oldenburg, Germany
| | - Chih-Huang Lai
- Dept. of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kai Liu
- Dept. of Physics, University of California, Davis, California 95616, USA
| |
Collapse
|
22
|
Gilbert DA, Grutter AJ, Arenholz E, Liu K, Kirby BJ, Borchers JA, Maranville BB. Structural and magnetic depth profiles of magneto-ionic heterostructures beyond the interface limit. Nat Commun 2016; 7:12264. [PMID: 27447691 PMCID: PMC4961844 DOI: 10.1038/ncomms12264] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/16/2016] [Indexed: 01/04/2023] Open
Abstract
Electric field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have been prominently featured in the modification of interface characteristics. Here, we demonstrate magnetoelectric coupling moderated by voltage-driven oxygen migration beyond the interface in relatively thick AlOx/GdOx/Co(15 nm) films. Oxygen migration and Co magnetization are quantitatively mapped with polarized neutron reflectometry under electro-thermal conditioning. The depth-resolved profiles uniquely identify interfacial and bulk behaviours and a semi-reversible control of the magnetization. Magnetometry measurements suggest changes in the microstructure which disrupt long-range ferromagnetic ordering, resulting in an additional magnetically soft phase. X-ray spectroscopy confirms changes in the Co oxidation state, but not in the Gd, suggesting that the GdOx transmits oxygen but does not source or sink it. These results together provide crucial insight into controlling magnetism via magneto-ionic motion, both at interfaces and throughout the bulk of the films.
Collapse
Affiliation(s)
- Dustin A Gilbert
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, 20899, Maryland, USA.
| | - Alexander J Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, 20899, Maryland, USA.
| | - Elke Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, 94720, California, USA
| | - Kai Liu
- Physics Department, University of California, Davis, 95616, California, USA
| | - B J Kirby
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, 20899, Maryland, USA
| | - Julie A Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, 20899, Maryland, USA
| | - Brian B Maranville
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, 20899, Maryland, USA
| |
Collapse
|
23
|
Gilbert DA, Maranville BB, Balk AL, Kirby BJ, Fischer P, Pierce DT, Unguris J, Borchers JA, Liu K. Realization of ground-state artificial skyrmion lattices at room temperature. Nat Commun 2015; 6:8462. [PMID: 26446515 PMCID: PMC4633628 DOI: 10.1038/ncomms9462] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/23/2015] [Indexed: 11/17/2022] Open
Abstract
The topological nature of magnetic skyrmions leads to extraordinary properties that provide new insights into fundamental problems of magnetism and exciting potentials for novel magnetic technologies. Prerequisite are systems exhibiting skyrmion lattices at ambient conditions, which have been elusive so far. Here, we demonstrate the realization of artificial Bloch skyrmion lattices over extended areas in their ground state at room temperature by patterning asymmetric magnetic nanodots with controlled circularity on an underlayer with perpendicular magnetic anisotropy (PMA). Polarity is controlled by a tailored magnetic field sequence and demonstrated in magnetometry measurements. The vortex structure is imprinted from the dots into the interfacial region of the underlayer via suppression of the PMA by a critical ion-irradiation step. The imprinted skyrmion lattices are identified directly with polarized neutron reflectometry and confirmed by magnetoresistance measurements. Our results demonstrate an exciting platform to explore room-temperature ground-state skyrmion lattices.
Collapse
Affiliation(s)
- Dustin A. Gilbert
- Department of Physics, University of California, Davis, California 95616, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Brian B. Maranville
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Andrew L. Balk
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Maryland Nanocenter, University of Maryland, College Park, Maryland 20742, USA
| | - Brian J. Kirby
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Peter Fischer
- Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Santa Cruz, California 94056, USA
| | - Daniel T. Pierce
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - John Unguris
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Julie A. Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Kai Liu
- Department of Physics, University of California, Davis, California 95616, USA
| |
Collapse
|
24
|
Gilbert DA, Ye L, Varea A, Agramunt-Puig S, del Valle N, Navau C, López-Barbera JF, Buchanan KS, Hoffmann A, Sánchez A, Sort J, Liu K, Nogués J. A new reversal mode in exchange coupled antiferromagnetic/ferromagnetic disks: distorted viscous vortex. NANOSCALE 2015; 7:9878-9885. [PMID: 25965577 DOI: 10.1039/c5nr01856k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Magnetic vortices have generated intense interest in recent years due to their unique reversal mechanisms, fascinating topological properties, and exciting potential applications. In addition, the exchange coupling of magnetic vortices to antiferromagnets has also been shown to lead to a range of novel phenomena and functionalities. Here we report a new magnetization reversal mode of magnetic vortices in exchange coupled Ir20Mn80/Fe20Ni80 microdots: distorted viscous vortex reversal. In contrast to the previously known or proposed reversal modes, the vortex is distorted close to the interface and viscously dragged due to the uncompensated spins of a thin antiferromagnet, which leads to unexpected asymmetries in the annihilation and nucleation fields. These results provide a deeper understanding of the physics of exchange coupled vortices and may also have important implications for applications involving exchange coupled nanostructures.
Collapse
|
25
|
Das GK, Bonifacio CS, De Rojas J, Liu K, van Benthem K, Kennedy IM. Ultra-long Magnetic Nanochains for Highly Efficient Arsenic Removal from Water. JOURNAL OF MATERIALS CHEMISTRY. A 2014; 2:12974-12981. [PMID: 25254112 PMCID: PMC4170064 DOI: 10.1039/c4ta02614d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The contamination of drinking water with naturally occurring arsenic is a global health threat. Filters that are packed with adsorbent media with a high affinity for arsenic have been used to de-contaminate water - generally iron or aluminium oxides are favored materials. Recently, nanoparticles have been introduced as adsorbent media due to their superior efficiency compared to their bulk counter-parts. An efficient nanoadsorbent should ideally possess high surface area, be easy to synthesize, and most importantly offer a high arsenic removal capacity. Achieving all the key features in a single step synthesis is an engineering challenge. We have successfully engineered such a material in the form of nanochains synthesized via a one step flame synthesis. The ultra-long γ-Fe2O3 nanochains possess high surface area (151.12 m2 g-1), large saturation magnetization (77.1 emu g-1) that aids in their gas phase self-assembly into long chains in an external magnetic field, along with an extraordinary arsenic removal capacity (162 mg.g-1). A filter made with this material exhibited a relatively low-pressure drop and very little break-through of the iron oxide across the filter.
Collapse
Affiliation(s)
| | | | - Julius De Rojas
- Department of Physics One Shields Avenue, University of California, Davis, CA, 95616
| | - Kai Liu
- Department of Physics One Shields Avenue, University of California, Davis, CA, 95616
| | | | - Ian M. Kennedy
- Department of Mechanical and Aerospace Engineering
- Corresponding author,
| |
Collapse
|