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Resonant Soft X-ray Reflectivity in the Study of Magnetic Properties of Low-Dimensional Systems. MAGNETOCHEMISTRY 2021. [DOI: 10.3390/magnetochemistry7100136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this review, the technique of resonant soft X-ray reflectivity in the study of magnetic low-dimensional systems is discussed. This technique is particularly appealing in the study of magnetization at buried interfaces and to discriminate single elemental contributions to magnetism, even when this is ascribed to few atoms. The major fields of application are described, including magnetic proximity effects, thin films of transition metals and related oxides, and exchange-bias systems. The fundamental theoretical background leading to dichroism effects in reflectivity is also briefly outlined.
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2
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Chen Q, Liang J, Fang B, Zhu Y, Wang J, Lv W, Lv W, Cai J, Huang Z, Zhai Y, Zhang B, Zeng Z. Proximity effect of a two-dimensional van der Waals magnet Fe 3GeTe 2 on nickel films. NANOSCALE 2021; 13:14688-14693. [PMID: 34533556 DOI: 10.1039/d1nr03342e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent advances in two-dimensional van der Waals (2D vdW) magnets provide new platforms to study their magnetism in reduced dimensions. However, most of the studies performed to date have been limited to low temperatures. Here, we report the proximity effect of a 2D vdW magnet Fe3GeTe2 (FGT) on nickel (Ni) films at room temperature. Ferromagnetic resonance measurements show that FGT can increase the perpendicular magnetic anisotropy (PMA) and magnetic damping of the adjacent Ni film. Such an interfacial effect is observed at room temperature, and becomes more pronounced as the temperature decreases. A similar effect is also achieved in another 2D heterostructure of Cr2Ge2Te6/Ni, implying its universality in a variety of 2D magnetic materials. Our work provides a new approach for utilizing 2D magnets in spintronics at room temperature.
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Affiliation(s)
- Qian Chen
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
| | - Jian Liang
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Bin Fang
- Nanchang Nano-Devices and Technologies Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang, Jiangxi, 330200, China
| | - Yonghui Zhu
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Jiachen Wang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
| | - Weiming Lv
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
- Nanchang Nano-Devices and Technologies Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang, Jiangxi, 330200, China
| | - Wenxing Lv
- Physics Laboratory, Industrial Training Center, Shenzhen Polytechnic, Shenzhen, Guangdong, 518055, China
| | - Jialin Cai
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
- Nanchang Nano-Devices and Technologies Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang, Jiangxi, 330200, China
| | - Zhaocong Huang
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Ya Zhai
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Baoshun Zhang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
| | - Zhongming Zeng
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
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Mokkath JH. Effect of the interplay between layering sequence permutations and thickness on the magnetic features of Fe/Ni/Gd hetero-films. Phys Chem Chem Phys 2020; 22:12082-12091. [DOI: 10.1039/d0cp01712d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of the interplay between layering sequence permutations and film thickness on the temperature-dependent magnetization and spin structure of Fe/Ni/Gd hetero-films (sizes: 10 nm × 10 nm × d nm and 20 nm × 20 nm × d nm, where d is the film thickness and with all possible layer sequence permutations) is investigated in the framework of an atomistic spin dynamics formalism.
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Affiliation(s)
- Junais Habeeb Mokkath
- Quantum Nanophotonics Simulations Lab
- Department of Physics
- Kuwait College of Science And Technology
- Kuwait
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4
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Basha MA, Prajapat CL, Gupta M, Bhatt H, Kumar Y, Ghosh SK, Karki V, Basu S, Singh S. Interface induced magnetic properties of Gd/Co heterostructures. Phys Chem Chem Phys 2018; 20:21580-21589. [PMID: 30095828 DOI: 10.1039/c8cp02909a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Antiferromagnetic coupling between rare-earth and transition metal ferromagnetic layers gives rise to various magnetic ground states in heterostructures of these materials. Interface structure and morphology tend to play important roles in magnetic properties of such systems. Interface induced magnetization in Gd/Co heterostructures has been studied using a combination of structural and magnetic characterization techniques. The interface morphology of the Gd/Co system was varied by growing Gd/Co multilayers using magnetron sputtering under different argon partial pressures. Interfacial properties were further modified by annealing the multilayers under high vacuum. The macroscopic magnetization measurements have been correlated with depth dependent structure and magnetic properties of multilayers studied using X-ray and polarized neutron reflectometry techniques. Secondary ion mass spectrometry measurements from both as-deposited and annealed samples also confirmed modification at the interfaces. It has been shown that the interface structure, together with roughness, leads to a unique low-temperature magnetic phase characterized by twisting of Gd and Co moments.
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Affiliation(s)
- M A Basha
- Solid Sate Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
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Autieri C, Sanyal B. A systematic study of 4d and 5d transition metal mediated exchange coupling between Fe and Gd nanolaminates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:465802. [PMID: 29057756 DOI: 10.1088/1361-648x/aa8f1e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a systematic study of the magnetic coupling between iron and gadolinium layers intermediated by 4d and 5d transition metals using density functional theory. We demonstrate that it is possible to find a magnetic coupling for most of them. In particular, for the early transition metals (d 1, d 2, d 3 and d 4), a ferromagnetic coupling occurs even stronger than the 3d interlayers. Atomic size and the electronic configuration of the transition metals are crucial for the nature of the coupling. All the open shell transition metals present induced magnetic moments. By increasing the number of interlayers, an oscillating behavior in the magnetic coupling was found and the magnetic coupling goes to zero beyond four spacer layers. Using Monte Carlo simulations, we demonstrate that the interlayer strongly enhances the critical temperature in the Gd layers closest to the interface.
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Affiliation(s)
- Carmine Autieri
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
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Drovosekov AB, Kreines NM, Savitsky AO, Kravtsov EA, Ryabukhina MV, Proglyado VV, Ustinov VV. Magnetization and ferromagnetic resonance in a Fe/Gd multilayer: experiment and modelling. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:115802. [PMID: 27997372 DOI: 10.1088/1361-648x/aa54f1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Static and dynamic magnetic properties of a [Fe(35 Å)/Gd(50 Å)]12 superlattice are investigated experimentally in the temperature range 5-295 K using SQUID magnetometery and the ferromagnetic resonance (FMR) technique at frequencies 7-38 GHz. The obtained magnetization curves and FMR spectra are analysed theoretically using numerical simulation on the basis of the effective field model. At every given temperature, both static and resonance experimental data can be approximated well within the proposed model. However, a considerable temperature dependence of the effective field parameter in gadolinium layers has to be taken into account to achieve reasonable agreement with the experimental data in the entire temperature range studied. To describe the peculiarities of experimental FMR spectra, a non-local diffusion-type absorption term in Landau-Lifshitz equations is considered in addition to the Gilbert damping term. Possible reasons for the observed effects are discussed.
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Affiliation(s)
- A B Drovosekov
- P. L. Kapitza Institute for Physical Problems RAS, Kosygina St. 2, 119334 Moscow, Russia
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7
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Singh S, Freeland JW, Fitzsimmons MR, Jeen H, Biswas A. Composition dependence of charge and magnetic length scales in mixed valence manganite thin films. Sci Rep 2016; 6:29632. [PMID: 27461993 PMCID: PMC4995356 DOI: 10.1038/srep29632] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/22/2016] [Indexed: 11/17/2022] Open
Abstract
Mixed-valence manganese oxides present striking properties like the colossal magnetoresistance, metal-insulator transition (MIT) that may result from coexistence of ferromagnetic, metallic and insulating phases. Percolation of such phase coexistence in the vicinity of MIT leads to first-order transition in these manganites. However the length scales over which the electronic and magnetic phases are separated across MIT which appears compelling for bulk systems has been elusive in (La1−yPry)1−xCaxMnO3 films. Here we show the in-plane length scale over which charge and magnetism are correlated in (La0.4Pr0.6)1−xCaxMnO3 films with x = 0.33 and 0.375, across the MIT temperature. We combine electrical transport (resistance) measurements, x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD), and specular/off-specular x-ray resonant magnetic scattering (XRMS) measurements as a function of temperature to elucidate relationships between electronic, magnetic and morphological structure of the thin films. Using off-specular XRMS we obtained the charge-charge and charge-magnetic correlation length of these LPCMO films across the MIT. We observed different charge-magnetic correlation length for two films which increases below the MIT. The different correlation length shown by two films may be responsible for different macroscopic (transport and magnetic) properties.
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Affiliation(s)
- Surendra Singh
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 India
| | - J W Freeland
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M R Fitzsimmons
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - H Jeen
- Department of Physics, University of Florida, Gainesville, FL 32611, USA.,Department of Physics, Pusan National University, Busan 609-735, Korea
| | - A Biswas
- Department of Physics, University of Florida, Gainesville, FL 32611, USA
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8
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Autieri C, Kumar PA, Walecki D, Webers S, Gubbins MA, Wende H, Sanyal B. Recipe for High Moment Materials with Rare-earth and 3d Transition Metal Composites. Sci Rep 2016; 6:29307. [PMID: 27381456 PMCID: PMC4933949 DOI: 10.1038/srep29307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/07/2016] [Indexed: 11/09/2022] Open
Abstract
Materials with high volume magnetization are perpetually needed for the generation of sufficiently large magnetic fields by writer pole of magnetic hard disks, especially for achieving increased areal density in storage media. In search of suitable materials combinations for this purpose, we have employed density functional theory to predict the magnetic coupling between iron and gadolinium layers separated by one to several monolayers of 3d transition metals (Sc-Zn). We demonstrate that it is possible to find ferromagnetic coupling for many of them and in particular for the early transition metals giving rise to high moment. Cr and Mn are the only elements able to produce a significant ferromagnetic coupling for thicker spacer layers. We also present experimental results on two trilayer systems Fe/Sc/Gd and Fe/Mn/Gd. From the experiments, we confirm a ferromagnetic coupling between Fe and Gd across a 3 monolayers Sc spacer or a Mn spacer thicker than 1 monolayer. In addition, we observe a peculiar dependence of Fe/Gd magnetic coupling on the Mn spacer thickness.
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Affiliation(s)
- Carmine Autieri
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - P. Anil Kumar
- Faculty of Physics Duisburg-Essen (CeNIDE), University of Duisburg-Essen, D-47057 Duisburg, Germany
| | - Dirk Walecki
- Faculty of Physics Duisburg-Essen (CeNIDE), University of Duisburg-Essen, D-47057 Duisburg, Germany
| | - Samira Webers
- Faculty of Physics Duisburg-Essen (CeNIDE), University of Duisburg-Essen, D-47057 Duisburg, Germany
| | - Mark A. Gubbins
- Seagate Technology, 1 Disc Drive, Springtown, Northern Ireland BT48 0BF, United Kingdom
| | - Heiko Wende
- Faculty of Physics Duisburg-Essen (CeNIDE), University of Duisburg-Essen, D-47057 Duisburg, Germany
| | - Biplab Sanyal
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
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9
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Observation of an atomic exchange bias effect in DyCo4 film. Sci Rep 2015; 5:18377. [PMID: 26675537 PMCID: PMC4682085 DOI: 10.1038/srep18377] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/03/2015] [Indexed: 11/30/2022] Open
Abstract
The fundamental important and technologically widely employed exchange bias effect occurs in general in bilayers of magnetic thin films consisting of antiferromagnetic and ferromagnetic layers where the hard magnetization behavior of an antiferromagnetic thin film causes a shift in the magnetization curve of a soft ferromagnetic film. The minimization of the single magnetic grain size to increase the storage density and the subsequent demand for magnetic materials with very high magnetic anisotropy requires a system with high HEB. Here we report an extremely high HEB of 4 Tesla observed in a single amorphous DyCo4 film close to room temperature. The origin of the exchange bias can be associated with the variation of the magnetic behavior from the surface towards the bulk part of the film revealed by X-ray absorption spectroscopy and X-ray magnetic circular dichroism techniques utilizing the bulk sensitive transmission and the surface sensitive total electron yield modes. The competition between the atomic exchange coupling in the single film and the Zeeman interaction lead to an intrinsic exchanged coupled system and the so far highest exchange bias effect HEB = 4 Tesla reported in a single film, which is accommodated by a partial domain wall formation.
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10
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Fan T, Grychtol P, Knut R, Hernández-García C, Hickstein DD, Zusin D, Gentry C, Dollar FJ, Mancuso CA, Hogle CW, Kfir O, Legut D, Carva K, Ellis JL, Dorney KM, Chen C, Shpyrko OG, Fullerton EE, Cohen O, Oppeneer PM, Milošević DB, Becker A, Jaroń-Becker AA, Popmintchev T, Murnane MM, Kapteyn HC. Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism. Proc Natl Acad Sci U S A 2015; 112:14206-11. [PMID: 26534992 PMCID: PMC4655510 DOI: 10.1073/pnas.1519666112] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.
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Affiliation(s)
- Tingting Fan
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440;
| | - Patrik Grychtol
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Ronny Knut
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Carlos Hernández-García
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440; Grupo de Investigación en Óptica Extrema, Universidad de Salamanca, Salamanca 37008, Spain
| | - Daniel D Hickstein
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Dmitriy Zusin
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Christian Gentry
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Franklin J Dollar
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | | | - Craig W Hogle
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Ofer Kfir
- Solid State Institute and Physics Department, Technion, Haifa 32000, Israel
| | - Dominik Legut
- IT4Innovations Center, VSB Technical University of Ostrava, CZ 708 33 Ostrava, Czech Republic; Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Charles University in Prague, CZ-12116 Prague 2, Czech Republic
| | - Karel Carva
- Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Charles University in Prague, CZ-12116 Prague 2, Czech Republic; Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Jennifer L Ellis
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Kevin M Dorney
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Cong Chen
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Oleg G Shpyrko
- Department of Physics, University of California San Diego, La Jolla, CA 92093
| | - Eric E Fullerton
- Center for Magnetic Recording Research, University of California San Diego, La Jolla, CA 92093-0401
| | - Oren Cohen
- Solid State Institute and Physics Department, Technion, Haifa 32000, Israel
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Dejan B Milošević
- Faculty of Science, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina; Academy of Sciences and Arts of Bosnia and Herzegovina, 71000 Sarajevo, Bosnia and Herzegovina; Max-Born-Institut, 12489 Berlin, Germany
| | - Andreas Becker
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | | | - Tenio Popmintchev
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
| | - Margaret M Murnane
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440;
| | - Henry C Kapteyn
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440
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11
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Schmitz-Antoniak C. X-ray absorption spectroscopy on magnetic nanoscale systems for modern applications. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:062501. [PMID: 26029938 DOI: 10.1088/0034-4885/78/6/062501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
X-ray absorption spectroscopy facilitated by state-of-the-art synchrotron radiation technology is presented as a powerful tool to study nanoscale systems, in particular revealing their static element-specific magnetic and electronic properties on a microscopic level. A survey is given on the properties of nanoparticles, nanocomposites and thin films covering a broad range of possible applications. It ranges from the ageing effects of iron oxide nanoparticles in dispersion for biomedical applications to the characterisation on a microscopic level of nanoscale systems for data storage devices. In this respect, new concepts for electrically addressable magnetic data storage devices are highlighted by characterising the coupling in a BaTiO(3)/CoFe(2)O(4) nanocomposite as prototypical model system. But classical magnetically addressable devices are also discussed on the basis of tailoring the magnetic properties of self-assembled ensembles of FePt nanoparticles for data storage and the high-moment material Fe/Cr/Gd for write heads. For the latter cases, the importance is emphasised of combining experimental approaches in x-ray absorption spectroscopy with density functional theory to gain a more fundamental understanding.
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Affiliation(s)
- Carolin Schmitz-Antoniak
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, D-47048 Duisburg, Germany
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12
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Mouketo L, Binggeli N, M'Passi-Mabiala B. Magnetism at the V/Gd interface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:186003. [PMID: 21393697 DOI: 10.1088/0953-8984/22/18/186003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Recent experimental investigations into the magnetic properties of V/Gd bilayers have shown that vanadium, which is nonmagnetic in the bulk, can acquire a magnetic moment in such systems. We have performed ab initio pseudopotential calculations to examine the magnetic behavior of V(110)/Gd(0001) bilayers for V layers with thicknesses up to 4 monolayers (ML). We considered both abrupt and atomic intermixed V/Gd interfaces. In both cases, the magnetic moment of the V layer is found to align antiparallel to the moment of the Gd layer, consistent with the experimental observation. However, the magnitude of the V moment at the abrupt interface is considerably smaller than the moments reported experimentally. In the presence of atomic intermixing, instead, substantially larger V moments are found, closer to the experimentally reported moments. On the basis of the calculated atomic and spin resolved density of states, we discuss the possible mechanism responsible for the observed Gd-V antiferromagnetic coupling.
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Affiliation(s)
- L Mouketo
- Groupe de Simulations Numériques en Magnétisme et Catalyse, Département de Physique, Université Marien NGouabi, BP 69, Brazzaville, Congo
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13
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Boada R, Laguna-Marco MA, Gallastegui JA, Castro GR, Chaboy J. X-ray magnetic circular dichroism measurements using an X-ray phase retarder on the BM25 A-SpLine beamline at the ESRF. JOURNAL OF SYNCHROTRON RADIATION 2010; 17:308-313. [PMID: 20400827 PMCID: PMC3025655 DOI: 10.1107/s0909049510005881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 02/12/2010] [Indexed: 05/29/2023]
Abstract
Circularly polarized X-rays produced by a diamond X-ray phase retarder of thickness 0.5 mm in the Laue transmission configuration have been used for recording X-ray magnetic circular dichroism (XMCD) on the bending-magnet beamline BM25A (SpLine) at the ESRF. Field reversal and helicity reversal techniques have been used to carry out the measurements. The performance of the experimental set-up has been demonstrated by recording XMCD in the energy range from 7 to 11 keV.
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Affiliation(s)
- Roberto Boada
- Instituto de Ciencia de Materiales de Aragón, Consejo Superior de Investigaciones Científicas, CSIC-Universidad de Zaragoza, Zaragoza, Spain.
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14
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Sanyal B, Antoniak C, Burkert T, Krumme B, Warland A, Stromberg F, Praetorius C, Fauth K, Wende H, Eriksson O. Forcing ferromagnetic coupling between rare-earth-metal and 3d ferromagnetic films. PHYSICAL REVIEW LETTERS 2010; 104:156402. [PMID: 20482001 DOI: 10.1103/physrevlett.104.156402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Indexed: 05/29/2023]
Abstract
Using density functional calculations, we have studied the magnetic properties of nanocomposites composed of rare-earth-metal elements in contact with 3d transition metals (Fe and Cr). We demonstrate the possibility to obtain huge magnetic moments in such nanocomposites, of order 10mu(B)/rare-earth-metal atom, with a potential to reach the maximum magnetic moment of Fe-Co alloys at the top of the so-called Slater-Pauling curve. A first experimental proof of concept is given by thin-film synthesis of Fe/Gd and Fe/Cr/Gd nanocomposites, in combination with x-ray magnetic circular dichroism.
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Affiliation(s)
- Biplab Sanyal
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.
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15
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Tonnerre JM, De Santis M, Grenier S, Tolentino HCN, Langlais V, Bontempi E, García-Fernández M, Staub U. Depth magnetization profile of a perpendicular exchange coupled system by soft-x-ray resonant magnetic reflectivity. PHYSICAL REVIEW LETTERS 2008; 100:157202. [PMID: 18518146 DOI: 10.1103/physrevlett.100.157202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Indexed: 05/26/2023]
Abstract
The magnetic profile across the interface of a perpendicular exchange coupled [NiO/CoO]3/Pt-Co/Pt(111) system is investigated. The magneto-optic Kerr effect reveals a strong coupling between the antiferromagnetic (AFM) oxide and the ferromagnetic (FM) Pt-Co layer, by an increasing coercivity and a rotation of the easy magnetization axis of the FM layer along the AFM spins. Soft x-ray resonant magnetic reflectivity is used to probe the spatial distribution of the out-of-plane magnetization inside the oxide above its ordering temperature. It extends over 1 nm and exhibits a change of sign.
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Affiliation(s)
- J M Tonnerre
- Institut Néel, CNRS & Université Joseph Fourier, Grenoble Cedex 9, France
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Haskel D, Lang JC, Islam Z, Cady A, Srajer G, van Veenendaal M, Canfield PC. Atomic origin of magnetocrystalline anisotropy in Nd(2)Fe(14)B. PHYSICAL REVIEW LETTERS 2005; 95:217207. [PMID: 16384180 DOI: 10.1103/physrevlett.95.217207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Indexed: 05/05/2023]
Abstract
The magnetic moment reversal at each of the two inequivalent Nd sites in a single crystal of ferromagnetic Nd(2)Fe(14)B is probed by dichroic resonant diffraction of circularly polarized x rays. The results, supported by theory, show that the c-axis intrinsic magnetic stability of this superior permanent magnetic material arises predominantly at one of the Nd sites (g). The other site (f) undermines magnetic stability by favoring a magnetic moment orientation in the basal plane.
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Affiliation(s)
- D Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Slnha SK, Freeland JW, Nelson CS, Srajer G. Resonant magnetic x‐ray scattering studies of magnetism at surfaces and interfaces. ACTA ACUST UNITED AC 2004. [DOI: 10.1080/08940880408603118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Prieto JL, Blamire MG, Evetts JE. Magnetoresistance in a constricted domain wall. PHYSICAL REVIEW LETTERS 2003; 90:027201. [PMID: 12570574 DOI: 10.1103/physrevlett.90.027201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2002] [Indexed: 05/24/2023]
Abstract
We show that a thin Gd layer inserted between two thicker layers of permalloy contains an in-plane domain wall whose width can be controlled by varying the thickness of the Gd layer. The magnetoresistance of this structure has been measured with the current perpendicular to the plane, thus eliminating spurious contributions which have complicated previous measurements. This is the first measurement to show unambiguously that the domain wall contributes an additional resistance whose magnitude is in good agreement with theory.
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Affiliation(s)
- José L Prieto
- Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
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