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Vijayakumar J, Savchenko TM, Bracher DM, Lumbeeck G, Béché A, Verbeeck J, Vajda Š, Nolting F, Vaz C, Kleibert A. Absence of a pressure gap and atomistic mechanism of the oxidation of pure Co nanoparticles. Nat Commun 2023; 14:174. [PMID: 36635276 PMCID: PMC9837083 DOI: 10.1038/s41467-023-35846-0] [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: 09/14/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023] Open
Abstract
Understanding chemical reactivity and magnetism of 3d transition metal nanoparticles is of fundamental interest for applications in fields ranging from spintronics to catalysis. Here, we present an atomistic picture of the early stage of the oxidation mechanism and its impact on the magnetism of Co nanoparticles. Our experiments reveal a two-step process characterized by (i) the initial formation of small CoO crystallites across the nanoparticle surface, until their coalescence leads to structural completion of the oxide shell passivating the metallic core; (ii) progressive conversion of the CoO shell to Co3O4 and void formation due to the nanoscale Kirkendall effect. The Co nanoparticles remain highly reactive toward oxygen during phase (i), demonstrating the absence of a pressure gap whereby a low reactivity at low pressures is postulated. Our results provide an important benchmark for the development of theoretical models for the chemical reactivity in catalysis and magnetism during metal oxidation at the nanoscale.
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Affiliation(s)
- Jaianth Vijayakumar
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Tatiana M. Savchenko
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - David M. Bracher
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Gunnar Lumbeeck
- grid.5284.b0000 0001 0790 3681EMAT, University of Antwerp, 2020 Antwerpen, Belgium
| | - Armand Béché
- grid.5284.b0000 0001 0790 3681EMAT, University of Antwerp, 2020 Antwerpen, Belgium
| | - Jo Verbeeck
- grid.5284.b0000 0001 0790 3681EMAT, University of Antwerp, 2020 Antwerpen, Belgium
| | - Štefan Vajda
- grid.418095.10000 0001 1015 3316Department of Nanocatalysis, J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 2155/3, 18223 Prague, Czech Republic
| | - Frithjof Nolting
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - C.A.F. Vaz
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Armin Kleibert
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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2
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Honecker D, Bersweiler M, Erokhin S, Berkov D, Chesnel K, Venero DA, Qdemat A, Disch S, Jochum JK, Michels A, Bender P. Using small-angle scattering to guide functional magnetic nanoparticle design. NANOSCALE ADVANCES 2022; 4:1026-1059. [PMID: 36131777 PMCID: PMC9417585 DOI: 10.1039/d1na00482d] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 01/15/2022] [Indexed: 05/14/2023]
Abstract
Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent tunability of their magnetic properties. To optimize particles for a specific application, it is crucial to interrelate their performance with their structural and magnetic properties. This review presents the advantages of small-angle X-ray and neutron scattering techniques for achieving a detailed multiscale characterization of magnetic nanoparticles and their ensembles in a mesoscopic size range from 1 to a few hundred nanometers with nanometer resolution. Both X-rays and neutrons allow the ensemble-averaged determination of structural properties, such as particle morphology or particle arrangement in multilayers and 3D assemblies. Additionally, the magnetic scattering contributions enable retrieving the internal magnetization profile of the nanoparticles as well as the inter-particle moment correlations caused by interactions within dense assemblies. Most measurements are used to determine the time-averaged ensemble properties, in addition advanced small-angle scattering techniques exist that allow accessing particle and spin dynamics on various timescales. In this review, we focus on conventional small-angle X-ray and neutron scattering (SAXS and SANS), X-ray and neutron reflectometry, gracing-incidence SAXS and SANS, X-ray resonant magnetic scattering, and neutron spin-echo spectroscopy techniques. For each technique, we provide a general overview, present the latest scientific results, and discuss its strengths as well as sample requirements. Finally, we give our perspectives on how future small-angle scattering experiments, especially in combination with micromagnetic simulations, could help to optimize the performance of magnetic nanoparticles for specific applications.
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Affiliation(s)
- Dirk Honecker
- ISIS Neutron and Muon Facility, Rutherford Appleton Laboratory Didcot OX11 0QX UK
| | - Mathias Bersweiler
- Department of Physics and Materials Science, University of Luxembourg 162A Avenue de La Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Sergey Erokhin
- General Numerics Research Lab Moritz-von-Rohr-Straße 1A D-07745 Jena Germany
| | - Dmitry Berkov
- General Numerics Research Lab Moritz-von-Rohr-Straße 1A D-07745 Jena Germany
| | - Karine Chesnel
- Brigham Young University, Department of Physics and Astronomy Provo Utah 84602 USA
| | - Diego Alba Venero
- ISIS Neutron and Muon Facility, Rutherford Appleton Laboratory Didcot OX11 0QX UK
| | - Asma Qdemat
- Universität zu Köln, Department für Chemie Luxemburger Straße 116 D-50939 Köln Germany
| | - Sabrina Disch
- Universität zu Köln, Department für Chemie Luxemburger Straße 116 D-50939 Köln Germany
| | - Johanna K Jochum
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München Lichtenbergstraße 1 85748 Garching Germany
| | - Andreas Michels
- Department of Physics and Materials Science, University of Luxembourg 162A Avenue de La Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Philipp Bender
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München Lichtenbergstraße 1 85748 Garching Germany
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3
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Gupta K, Jha PK, Dadwal A, Debnath AK, Jaiswal I, Rana S, Joy PA, Ballav N. Embedding S = 1/2 Kagome-like Lattice in Reduced Graphene Oxide. J Phys Chem Lett 2019; 10:2663-2668. [PMID: 31050902 DOI: 10.1021/acs.jpclett.9b00839] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
An elegant platform to explore frustrated magnetism is the kagome spin lattice. In this work, clinoatacamite, a naturally occurring S = 1/2 kagome-like antiferromagnetic insulator, is synthesized in water at ambient pressure for the first time from a cuprous chloride (CuCl) precursor whereby Cu(I) was spontaneously oxidized to Cu(II) in the form of clinoatacamite [Cu2(OH)3Cl] with a simultaneous reduction of graphene oxide (GO) to reduced graphene oxide (rGO) in one pot. A stable nanocomposite of phase-pure clinoatacamite nanocrystals embedded in the rGO matrix was isolated. The clinoatacamite-rGO nanocomposite was determined to be magnetically active with a markedly enhanced coercive field of ∼2500 Oe at 5 K as well as electronically active with a conductivity value of ∼200 S·m-1 at 300 K. Our results illustrate an avenue of combining exotic magnetic and electronic lattices without impeding their individual characteristics and synergistically generating a new class of magnetic semiconductors.
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Affiliation(s)
- Kriti Gupta
- Department of Chemistry , Indian Institute of Science Education and Research (IISER) , Pune 411008 , India
| | - Plawan Kumar Jha
- Department of Chemistry , Indian Institute of Science Education and Research (IISER) , Pune 411008 , India
| | - Arun Dadwal
- Physical and Materials Chemistry Division , National Chemical Laboratory (NCL) , Pune 411008 , India
| | - Anil K Debnath
- Thin Film Devices Section, Technical Physics Division , Bhabha Atomic Research Centre (BARC) , Mumbai 400085 , India
| | - Ishan Jaiswal
- Department of Chemistry , Indian Institute of Science Education and Research (IISER) , Pune 411008 , India
| | - Shammi Rana
- Department of Chemistry , Indian Institute of Science Education and Research (IISER) , Pune 411008 , India
| | - Pattayil A Joy
- Physical and Materials Chemistry Division , National Chemical Laboratory (NCL) , Pune 411008 , India
| | - Nirmalya Ballav
- Department of Chemistry , Indian Institute of Science Education and Research (IISER) , Pune 411008 , India
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4
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Tinti G, Marchetto H, Vaz CAF, Kleibert A, Andrä M, Barten R, Bergamaschi A, Brückner M, Cartier S, Dinapoli R, Franz T, Fröjdh E, Greiffenberg D, Lopez-Cuenca C, Mezza D, Mozzanica A, Nolting F, Ramilli M, Redford S, Ruat M, Ruder C, Schädler L, Schmidt T, Schmitt B, Schütz F, Shi X, Thattil D, Vetter S, Zhang J. The EIGER detector for low-energy electron microscopy and photoemission electron microscopy. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:963-974. [PMID: 28862618 DOI: 10.1107/s1600577517009109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 06/18/2017] [Indexed: 06/07/2023]
Abstract
EIGER is a single-photon-counting hybrid pixel detector developed at the Paul Scherrer Institut, Switzerland. It is designed for applications at synchrotron light sources with photon energies above 5 keV. Features of EIGER include a small pixel size (75 µm × 75 µm), a high frame rate (up to 23 kHz), a small dead-time between frames (down to 3 µs) and a dynamic range up to 32-bit. In this article, the use of EIGER as a detector for electrons in low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) is reported. It is demonstrated that, with only a minimal modification to the sensitive part of the detector, EIGER is able to detect electrons emitted or reflected by the sample and accelerated to 8-20 keV. The imaging capabilities are shown to be superior to the standard microchannel plate detector for these types of applications. This is due to the much higher signal-to-noise ratio, better homogeneity and improved dynamic range. In addition, the operation of the EIGER detector is not affected by radiation damage from electrons in the present energy range and guarantees more stable performance over time. To benchmark the detector capabilities, LEEM experiments are performed on selected surfaces and the magnetic and electronic properties of individual iron nanoparticles with sizes ranging from 8 to 22 nm are detected using the PEEM endstation at the Surface/Interface Microscopy (SIM) beamline of the Swiss Light Source.
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Affiliation(s)
- G Tinti
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - H Marchetto
- ELMITEC Elektronenmikroskopie GmbH, D-38678 Clausthal-Zellerfeld, Germany
| | - C A F Vaz
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Kleibert
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Andrä
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - R Barten
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Bergamaschi
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Brückner
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Cartier
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - R Dinapoli
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Franz
- ELMITEC Elektronenmikroskopie GmbH, D-38678 Clausthal-Zellerfeld, Germany
| | - E Fröjdh
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D Greiffenberg
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - C Lopez-Cuenca
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D Mezza
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Mozzanica
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - F Nolting
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Ramilli
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Redford
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Ruat
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Ch Ruder
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - L Schädler
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Th Schmidt
- Fritz-Haber-Institute of the Max-Planck-Society, Department of Chemical Physics, D-14195 Berlin, Germany
| | - B Schmitt
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - F Schütz
- ELMITEC Elektronenmikroskopie GmbH, D-38678 Clausthal-Zellerfeld, Germany
| | - X Shi
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D Thattil
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Vetter
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Zhang
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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5
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Gatel C, Bonilla FJ, Meffre A, Snoeck E, Warot-Fonrose B, Chaudret B, Lacroix LM, Blon T. Size-Specific Spin Configurations in Single Iron Nanomagnet: From Flower to Exotic Vortices. NANO LETTERS 2015; 15:6952-7. [PMID: 26407034 DOI: 10.1021/acs.nanolett.5b02892] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The different spin configurations in the vicinity of the single-domain/vortex transition are reported in isolated magnetic nanoparticles. By combining chemical synthesis, electron holography in a dedicated transmission electron microscope and micromagnetic simulations, we establish the "magnetic configurations vs size" phase diagram of Fe single-crystalline nanocubes. Room temperature high resolution magnetic maps reveal the transition between single-domain and vortex states for Fe nanocubes from 25 to 27 nm, respectively. An intermediate spin configuration consisting of an ⟨111⟩ vortex is for the first time evidenced.
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Affiliation(s)
- Christophe Gatel
- Centre d'Elaboration de Matériaux et d'Etudes Structurales, CEMES-CNRS , 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse, France
| | - Francisco Javier Bonilla
- Laboratoire de Physique et Chimie des Nano-Objets, LPCNO, UMR5215 INSA-UPS-CNRS, Université de Toulouse; Institut National des Sciences Appliquées , 135 avenue de Rangueil, 31077 Toulouse, France
| | - Anca Meffre
- Laboratoire de Physique et Chimie des Nano-Objets, LPCNO, UMR5215 INSA-UPS-CNRS, Université de Toulouse; Institut National des Sciences Appliquées , 135 avenue de Rangueil, 31077 Toulouse, France
| | - Etienne Snoeck
- Centre d'Elaboration de Matériaux et d'Etudes Structurales, CEMES-CNRS , 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse, France
| | - Bénédicte Warot-Fonrose
- Centre d'Elaboration de Matériaux et d'Etudes Structurales, CEMES-CNRS , 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse, France
| | - Bruno Chaudret
- Laboratoire de Physique et Chimie des Nano-Objets, LPCNO, UMR5215 INSA-UPS-CNRS, Université de Toulouse; Institut National des Sciences Appliquées , 135 avenue de Rangueil, 31077 Toulouse, France
| | - Lise-Marie Lacroix
- Laboratoire de Physique et Chimie des Nano-Objets, LPCNO, UMR5215 INSA-UPS-CNRS, Université de Toulouse; Institut National des Sciences Appliquées , 135 avenue de Rangueil, 31077 Toulouse, France
| | - Thomas Blon
- Laboratoire de Physique et Chimie des Nano-Objets, LPCNO, UMR5215 INSA-UPS-CNRS, Université de Toulouse; Institut National des Sciences Appliquées , 135 avenue de Rangueil, 31077 Toulouse, France
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6
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Fischer P, Ohldag H. X-rays and magnetism. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:094501. [PMID: 26288956 DOI: 10.1088/0034-4885/78/9/094501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities. To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution. This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques.
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Affiliation(s)
- Peter Fischer
- Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, USA. Physics Department, University of California Santa Cruz, 1156 High St, Santa Cruz, CA 94056, USA
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7
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Effect of substrate interface on the magnetism of supported iron nanoparticles. Ultramicroscopy 2015; 159 Pt 3:513-9. [PMID: 26051656 DOI: 10.1016/j.ultramic.2015.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 04/24/2015] [Accepted: 05/06/2015] [Indexed: 11/23/2022]
Abstract
In situ X-ray photo-emission electron microscopy is used to investigate the magnetic properties of iron nanoparticles deposited on different single crystalline substrates, including Si(001), Cu(001), W(110), and NiO(001). We find that, in our room temperature experiments, Fe nanoparticles deposited on Si(001) and Cu(001) show both superparamagnetic and magnetically stable (blocked) ferromagnetic states, while Fe nanoparticles deposited on W(110) and NiO(001) show only superparamagnetic behaviour. The dependence of the magnetic behaviour of the Fe nanoparticles on the contact surface is ascribed to the different interfacial bonding energies, higher for W and NiO, and to a possible relaxation of point defects within the core of the nanoparticles on these substrates, that have been suggested to stabilise the ferromagnetic state at room temperature when deposited on more inert surfaces such as Si and Cu.
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8
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Ziegler P, Paul N, Müller-Buschbaum P, Wiedemann B, Kreuzpaintner W, Jutimoosik J, Yimnirun R, Setzer A, Esquinazi P, Böni P, Paul A. Self-organization of Fe clusters on mesoporous TiO2templates. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714021049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Fe layers with thicknesses between 5 and 100 nm were sputtered on mesoporous nanostructured anatase TiO2templates. The morphology of these hybrid films was probed with grazing-incidence small-angle X-ray scattering and X-ray reflectivity, complemented with magnetic measurements. Three different stages of growth were found, which are characterized by different correlation lengths for each stage. The magnetic behavior correlates with the different growth regimes. At very small thicknesses the TiO2template is coated and a porous Fe film results, with in-plane and out-of-plane magnetization components. With increasing thickness, agglomeration of Fe occurs and the magnetization gradually turns mostly in plane. At large thicknesses, the iron grows independently of the template and the magnetization is predominantly in plane with a bulk-like characteristic.
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9
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Giridhar P, Weidenfeller B, Zein El Abedin S, Endres F. Electrodeposition and Magnetic Characterization of Iron and Iron-Silicon Alloys from the Ionic Liquid 1-Butyl-1-methylpyrrolidinium Trifluoromethylsulfonate. Chemphyschem 2014; 15:3515-22. [DOI: 10.1002/cphc.201402406] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/13/2014] [Indexed: 11/09/2022]
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10
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Girovsky J, Buzzi M, Wäckerlin C, Siewert D, Nowakowski J, Oppeneer PM, Nolting F, Jung TA, Kleibert A, Ballav N. Investigating magneto-chemical interactions at molecule-substrate interfaces by X-ray photo-emission electron microscopy. Chem Commun (Camb) 2014; 50:5190-2. [PMID: 24418897 DOI: 10.1039/c3cc47726f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magneto-chemical interaction of spin-bearing molecules with substrates is interesting from a coordination chemistry point of view and relevant for spintronics. Unprecedented insight is provided by X-ray photo-emission electron microscopy combined with X-ray magnetic circular dichroism spectroscopy. Here the coupling of a Mn-porphyrin ad-layer to the ferromagnetic Co substrate through suitably modified interfaces is analyzed with this technique.
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Affiliation(s)
- Jan Girovsky
- Laboratory for Micro and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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11
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Balan A, Derlet PM, Rodríguez AF, Bansmann J, Yanes R, Nowak U, Kleibert A, Nolting F. Direct observation of magnetic metastability in individual iron nanoparticles. PHYSICAL REVIEW LETTERS 2014; 112:107201. [PMID: 24679323 DOI: 10.1103/physrevlett.112.107201] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Indexed: 06/03/2023]
Abstract
X-ray photoemission electron microscopy combined with x-ray magnetic circular dichroism is used to study the magnetic properties of individual iron nanoparticles with sizes ranging from 20 down to 8 nm. While the magnetocrystalline anisotropy of bulk iron suggests superparamagnetic behavior in this size range, ferromagnetically blocked particles are also found at all sizes. Spontaneous transitions from the blocked state to the superparamagnetic state are observed in single particles and suggest that the enhanced magnetic energy barriers in the ferromagnetic particles are due to metastable, structurally excited states with unexpected life times.
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Affiliation(s)
- Ana Balan
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Peter M Derlet
- Condensed Matter Theory Group, NUM, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Arantxa Fraile Rodríguez
- Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Joachim Bansmann
- Institute of Surface Chemistry and Catalysis, University of Ulm, 89069 Ulm, Germany
| | - Rocio Yanes
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Ulrich Nowak
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Armin Kleibert
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Frithjof Nolting
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
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12
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Giridhar P, Weidenfeller B, El Abedin SZ, Endres F. Electrodeposition of iron and iron–aluminium alloys in an ionic liquid and their magnetic properties. Phys Chem Chem Phys 2014; 16:9317-26. [DOI: 10.1039/c4cp00613e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Vaz CAF, Balan A, Nolting F, Kleibert A. In situ magnetic and electronic investigation of the early stage oxidation of Fe nanoparticles using X-ray photo-emission electron microscopy. Phys Chem Chem Phys 2014; 16:26624-30. [DOI: 10.1039/c4cp02725f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In situX-ray photoemission electron microscopy reveals the evolution of chemical composition and magnetism of individual iron nanoparticles during oxidation.
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Affiliation(s)
- C. A. F. Vaz
- Swiss Light Source
- Paul Scherrer Institut
- 5232 Villigen PSI, Switzerland
| | - A. Balan
- Swiss Light Source
- Paul Scherrer Institut
- 5232 Villigen PSI, Switzerland
| | - F. Nolting
- Swiss Light Source
- Paul Scherrer Institut
- 5232 Villigen PSI, Switzerland
| | - A. Kleibert
- Swiss Light Source
- Paul Scherrer Institut
- 5232 Villigen PSI, Switzerland
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14
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Suturin SM, Fedorov VV, Banshchikov AG, Baranov DA, Koshmak KV, Torelli P, Fujii J, Panaccione G, Amemiya K, Sakamaki M, Nakamura T, Tabuchi M, Pasquali L, Sokolov NS. Proximity effects and exchange bias in Co/MnF2(111) heterostructures studied by x-ray magnetic circular dichroism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:046002. [PMID: 23238356 DOI: 10.1088/0953-8984/25/4/046002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Cobalt nano-structured ultrathin films were grown on orthorhombic MnF(2) by molecular beam epitaxy on CaF(2) epitaxial layers deposited on Si(111) substrates. The Co film was grown at room temperature. It was found to be polycrystalline, forming nano-islands with height≈diameter≤10 nm. X-ray absorption evidences the chemical stability of the Co/MnF(2) interface. Remarkably, x-ray magnetic circular dichroism (XMCD) demonstrates that the Co induces a net magnetization on the Mn ions close to the interface. The magnetic moments of these Mn ions couple antiparallel to the Co and rotate upon field reversal following the magnetization of the Co both below and high above the Néel temperature of MnF(2) (T(N) = 67 K). The density of coupled Mn moments is found to be temperature dependent, with an equivalent thickness of ~1.5 MnF(2) monolayers at 20 K, decreasing to about ~0.5 ML as the temperature is raised to 300 K. Interestingly, the intensity of the Mn XMCD signal appears to be related to the coercivity of the Co layer. This behavior is interpreted in terms of the competition between thermal fluctuations, exchange coupling between Co and Mn at the interface and, at low temperature, the antiferromagnetic order in MnF(2).
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Affiliation(s)
- S M Suturin
- Solid State Physics Division, Ioffe Physical-Technical Institute of Russian Academy of Sciences, 26 Polytechnicheskaya str., 194021, St. Petersburg, Russia
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15
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Vaz CAF. Electric field control of magnetism in multiferroic heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:333201. [PMID: 22824827 DOI: 10.1088/0953-8984/24/33/333201] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We review the recent developments in the electric field control of magnetism in multiferroic heterostructures, which consist of heterogeneous materials systems where a magnetoelectric coupling is engineered between magnetic and ferroelectric components. The magnetoelectric coupling in these composite systems is interfacial in origin, and can arise from elastic strain, charge, and exchange bias interactions, with different characteristic responses and functionalities. Moreover, charge transport phenomena in multiferroic heterostructures, where both magnetic and ferroelectric order parameters are used to control charge transport, suggest new possibilities to control the conduction paths of the electron spin, with potential for device applications.
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Affiliation(s)
- C A F Vaz
- SwissFEL, Paul Scherrer Institut, Villigen PSI, Switzerland.
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16
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Ostler TA, Barker J, Evans RFL, Chantrell RW, Atxitia U, Chubykalo-Fesenko O, El Moussaoui S, Le Guyader L, Mengotti E, Heyderman LJ, Nolting F, Tsukamoto A, Itoh A, Afanasiev D, Ivanov BA, Kalashnikova AM, Vahaplar K, Mentink J, Kirilyuk A, Rasing T, Kimel AV. Ultrafast heating as a sufficient stimulus for magnetization reversal in a ferrimagnet. Nat Commun 2012; 3:666. [PMID: 22314362 DOI: 10.1038/ncomms1666] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 01/05/2012] [Indexed: 11/09/2022] Open
Abstract
The question of how, and how fast, magnetization can be reversed is a topic of great practical interest for the manipulation and storage of magnetic information. It is generally accepted that magnetization reversal should be driven by a stimulus represented by time-non-invariant vectors such as a magnetic field, spin-polarized electric current, or cross-product of two oscillating electric fields. However, until now it has been generally assumed that heating alone, not represented as a vector at all, cannot result in a deterministic reversal of magnetization, although it may assist this process. Here we show numerically and demonstrate experimentally a novel mechanism of deterministic magnetization reversal in a ferrimagnet driven by an ultrafast heating of the medium resulting from the absorption of a sub-picosecond laser pulse without the presence of a magnetic field.
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Affiliation(s)
- T A Ostler
- Department of Physics, University of York, York YO10 5DD, UK.
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17
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Antoniak C, Friedenberger N, Trunova A, Meckenstock R, Kronast F, Fauth K, Farle M, Wende H. Intrinsic Magnetism and Collective Magnetic Properties of Size-Selected Nanoparticles. NANOPARTICLES FROM THE GASPHASE 2012. [DOI: 10.1007/978-3-642-28546-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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18
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Saranu S, Selve S, Kaiser U, Han L, Wiedwald U, Ziemann P, Herr U. Effect of large mechanical stress on the magnetic properties of embedded Fe nanoparticles. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:268-75. [PMID: 21977439 PMCID: PMC3148048 DOI: 10.3762/bjnano.2.31] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 05/17/2011] [Indexed: 05/25/2023]
Abstract
Magnetic nanoparticles are promising candidates for next generation high density magnetic data storage devices. Data storage requires precise control of the magnetic properties of materials, in which the magnetic anisotropy plays a dominant role. Since the total magneto-crystalline anisotropy energy scales with the particle volume, the storage density in media composed of individual nanoparticles is limited by the onset of superparamagnetism. One solution to overcome this limitation is the use of materials with extremely large magneto-crystalline anisotropy. In this article, we follow an alternative approach by using magneto-elastic interactions to tailor the total effective magnetic anisotropy of the nanoparticles. By applying large biaxial stress to nanoparticles embedded in a non-magnetic film, it is demonstrated that a significant modification of the magnetic properties can be achieved. The stress is applied to the nanoparticles through expansion of the substrate during hydrogen loading. Experimental evidence for stress induced magnetic effects is presented based on temperature-dependent magnetization curves of superparamagnetic Fe particles. The results show the potential of the approach for adjusting the magnetic properties of nanoparticles, which is essential for application in future data storage media.
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Affiliation(s)
| | - Sören Selve
- Institute for Electron Microscopy,Ulm University, Germany
| | - Ute Kaiser
- Institute for Electron Microscopy,Ulm University, Germany
| | - Luyang Han
- Institute of Solid State Physics, Ulm University, Germany
| | - Ulf Wiedwald
- Institute of Solid State Physics, Ulm University, Germany
| | - Paul Ziemann
- Institute of Solid State Physics, Ulm University, Germany
| | - Ulrich Herr
- Institute for Micro- and Nanomaterials, Ulm University, Germany
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19
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Kronast F, Friedenberger N, Ollefs K, Gliga S, Tati-Bismaths L, Thies R, Ney A, Weber R, Hassel C, Römer FM, Trunova AV, Wirtz C, Hertel R, Dürr HA, Farle M. Element-specific magnetic hysteresis of individual 18 nm Fe nanocubes. NANO LETTERS 2011; 11:1710-1715. [PMID: 21391653 DOI: 10.1021/nl200242c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Correlating the electronic structure and magnetic response with the morphology and crystal structure of the same single ferromagnetic nanoparticle has been up to now an unresolved challenge. Here, we present measurements of the element-specific electronic structure and magnetic response as a function of magnetic field amplitude and orientation for chemically synthesized single Fe nanocubes with 18 nm edge length. Magnetic states and interactions of monomers, dimers, and trimers are analyzed by X-ray photoemission electron microscopy for different particle arrangements. The element-specific electronic structure can be probed and correlated with the changes of magnetic properties. This approach opens new possibilities for a deeper understanding of the collective response of magnetic nanohybrids in multifunctional materials and in nanomagnetic colloidal suspensions used in biomedical and engineering technologies.
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Affiliation(s)
- Florian Kronast
- Helmholtz Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
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20
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Kleibert A, Rosellen W, Getzlaff M, Bansmann J. Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:47-56. [PMID: 21977415 PMCID: PMC3045938 DOI: 10.3762/bjnano.2.6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 01/10/2011] [Indexed: 05/31/2023]
Abstract
BACKGROUND Magnetic nanostructures and nanoparticles often show novel magnetic phenomena not known from the respective bulk materials. In the past, several methods to prepare such structures have been developed - ranging from wet chemistry-based to physical-based methods such as self-organization or cluster growth. The preparation method has a significant influence on the resulting properties of the generated nanostructures. Taking chemical approaches, this influence may arise from the chemical environment, reaction kinetics and the preparation route. Taking physical approaches, the thermodynamics and the kinetics of the growth mode or - when depositing preformed clusters/nanoparticles on a surface - the landing kinetics and subsequent relaxation processes have a strong impact and thus need to be considered when attempting to control magnetic and structural properties of supported clusters or nanoparticles. RESULTS In this contribution we focus on mass-filtered Fe nanoparticles in a size range from 4 nm to 10 nm that are generated in a cluster source and subsequently deposited onto two single crystalline substrates: fcc Ni(111)/W(110) and bcc W(110). We use a combined approach of X-ray magnetic circular dichroism (XMCD), reflection high energy electron diffraction (RHEED) and scanning tunneling microscopy (STM) to shed light on the complex and size-dependent relation between magnetic properties, crystallographic structure, orientation and morphology. In particular XMCD reveals that Fe particles on Ni(111)/W(110) have a significantly lower (higher) magnetic spin (orbital) moment compared to bulk iron. The reduced spin moments are attributed to the random particle orientation being confirmed by RHEED together with a competition of magnetic exchange energy at the interface and magnetic anisotropy energy in the particles. The RHEED data also show that the Fe particles on W(110) - despite of the large lattice mismatch between iron and tungsten - are not strained. Thus, strain is most likely not the origin of the enhanced orbital moments as supposed before. Moreover, RHEED uncovers the existence of a spontaneous process for epitaxial alignment of particles below a critical size of about 4 nm. STM basically confirms the shape conservation of the larger particles but shows first indications for an unexpected reshaping occurring at the onset of self-alignment. CONCLUSION The magnetic and structural properties of nanoparticles are strongly affected by the deposition kinetics even when soft landing conditions are provided. The orientation of the deposited particles and thus their interface with the substrate strongly depend on the particle size with consequences regarding particularly the magnetic behavior. Spontaneous and epitaxial self-alignment can occur below a certain critical size. This may enable the obtainment of samples with controlled, uniform interfaces and crystallographic orientations even in a random deposition process. However, such a reorientation process might be accompanied by a complex reshaping of the particles.
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Affiliation(s)
- Armin Kleibert
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Wolfgang Rosellen
- Institut für Angewandte Physik, Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Mathias Getzlaff
- Institut für Angewandte Physik, Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Joachim Bansmann
- Institut für Oberflächenchemie und Katalyse, Universität Ulm, 89081 Ulm, Germany
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