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Klenov N, Khaydukov Y, Bakurskiy S, Morari R, Soloviev I, Boian V, Keller T, Kupriyanov M, Sidorenko A, Keimer B. Periodic Co/Nb pseudo spin valve for cryogenic memory. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:833-839. [PMID: 31019870 PMCID: PMC6466729 DOI: 10.3762/bjnano.10.83] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
We present a study of magnetic structures with controllable effective exchange energy for Josephson switches and memory applications. As a basis for a weak link we propose to use a periodic structure composed of ferromagnetic (F) layers spaced by thin superconductors (s). Our calculations based on the Usadel equations show that switching from parallel (P) to antiparallel (AP) alignment of neighboring F layers can lead to a significant enhancement of the critical current through the junction. To control the magnetic alignment we propose to use a periodic system whose unit cell is a pseudo spin valve of structure F1/s/F2/s where F1 and F2 are two magnetic layers having different coercive fields. In order to check the feasibility of controllable switching between AP and P states through the whole periodic structure, we prepared a superlattice [Co(1.5 nm)/Nb(8 nm)/Co(2.5 nm)/Nb(8 nm)]6 between two superconducting layers of Nb(25 nm). Neutron scattering and magnetometry data showed that parallel and antiparallel alignment can be controlled with a magnetic field of only several tens of Oersted.
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Affiliation(s)
- Nikolay Klenov
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
- All-Russian Research Institute of Automatics n.a. N.L. Dukhov (VNIIA), 127055, Moscow, Russia
| | - Yury Khaydukov
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Heinz Maier-Leibnitz Zentrum (MLZ), D-85748 Garching, Germany
| | - Sergey Bakurskiy
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
| | - Roman Morari
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
| | - Igor Soloviev
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
| | - Vladimir Boian
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
| | - Thomas Keller
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Heinz Maier-Leibnitz Zentrum (MLZ), D-85748 Garching, Germany
| | - Mikhail Kupriyanov
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
- Solid State Physics Department, KFU, 420008 Kazan, Russia
| | - Anatoli Sidorenko
- Institute of Electronic Engineering and Nanotechnologies ASM, MD2028 Kishinev, Moldova
| | - Bernhard Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
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Li Z, Liu X, Causer GL, Lin KW, Pong P, Holt SA, Klose F, Li YY. Structural evolution of a Ni/NiOx based supercapacitor in cyclic charging-discharging: A polarized neutron and X-ray reflectometry study. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.09.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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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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4
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Neutron Reflectivity. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-34243-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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5
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Amir SM, Gupta M, Gupta A, Stahn J, Wildes A. Surfactant induced symmetric and thermally stable interfaces in Cu/Co multilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:485003. [PMID: 22052849 DOI: 10.1088/0953-8984/23/48/485003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this work we studied Ag surfactant induced growth of Cu/Co multilayers. The Cu/Co multilayers were deposited using Ag surfactant by the ion beam sputtering technique. It was found that Ag surfactant balances the asymmetry between the surface free energies of Cu and Co. As a result, the Co-on-Cu and Cu-on-Co interfaces become sharp and symmetric and thereby improve the thermal stability of the multilayer. On the basis of obtained results, a mechanism leading to symmetric and stable interfaces in Cu/Co multilayers is discussed.
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Affiliation(s)
- S M Amir
- UGC-DAE Consortium for Scientific Research, University Campus, Indore, India
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Singh S, Basu S. Separation and correlation of structural and magnetic roughness in a Ni thin film by polarized off-specular neutron reflectometry. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:055010. [PMID: 21817297 DOI: 10.1088/0953-8984/21/5/055010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Diffuse (off-specular) neutron and x-ray reflectometry has been used extensively for the determination of interface morphology in solids and liquids. For neutrons, a novel possibility is off-specular reflectometry with polarized neutrons to determine the morphology of a magnetic interface. There have been few such attempts due to the lower brilliance of neutron sources, though magnetic interaction of neutrons with atomic magnetic moments is much easier to comprehend and easily tractable theoretically. We have obtained a simple and physically meaningful expression, under the Born approximation, for analyzing polarized diffuse (off-specular) neutron reflectivity (PDNR) data. For the first time PDNR data from a Ni film have been analyzed and separate chemical and magnetic morphologies have been quantified. Also specular polarized neutron reflectivity measurements have been carried out to measure the magnetic moment density profile of the Ni film. The fit to PDNR data results in a longer correlation length for in-plane magnetic roughness than for chemical (structural) roughness. The magnetic interface is smoother than the chemical interface.
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Affiliation(s)
- Surendra Singh
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-85, India
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Ott F. Neutron studies of magnetic oxide thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:264009. [PMID: 21694343 DOI: 10.1088/0953-8984/20/26/264009] [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
We describe the use of neutron scattering techniques such as reflectivity and diffraction for the study of oxide thin films. We first describe how neutron reflectivity can complement x-ray reflectivity for the study of some oxide materials. We then emphasize magnetic thin films which have become an important field of study in the 1990s, following the discovery of new phenomena in heterostructures: magnetic exchange coupling, exchange bias coupling at antiferro/ferromagnetic interfaces, enhanced magnetism in ultrathin films or tunnel magnetoresistance for example. We show how neutron scattering can provide detailed quantitative information about the magnetization depth profiles of thin films and about the magnetic order in epitaxial films.
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Affiliation(s)
- Frédéric Ott
- Laboratoire Léon Brillouin CEA/CNRS UMR 12, Centre d'Etudes de Saclay, 91191 Gif sur Yvette, Cedex, France
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Steadman P, Ali M, Hindmarch AT, Marrows CH, Hickey BJ, Langridge S, Dalgliesh RM, Foster S. Exchange bias in spin-engineered double superlattices. PHYSICAL REVIEW LETTERS 2002; 89:077201. [PMID: 12190551 DOI: 10.1103/physrevlett.89.077201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2002] [Indexed: 05/23/2023]
Abstract
Exchange bias has been observed in sputtered magnetic double superlattices which consist of a ferromagnetically coupled superlattice grown on an antiferromagnetically (AF) coupled superlattice. This system exhibits a parallel domain wall, a spin flop transition, and exchange bias when the anisotropy is large in the AF block. This work shows that neither the domain wall nor the spin flop are directly related to exchange bias but that the anisotropy is essential.
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Affiliation(s)
- P Steadman
- Department of Physics and Astronomy, E. C. Stoner Laboratory, University of Leeds, United Kingdom.
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Dalgliesh R. Application of off-specular scattering of X-rays and neutrons to the study of soft matter. Curr Opin Colloid Interface Sci 2002. [DOI: 10.1016/s1359-0294(02)00054-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Nagy DL, Bottyán L, Croonenborghs B, Deák L, Degroote B, Dekoster J, Lauter HJ, Lauter-Pasyuk V, Leupold O, Major M, Meersschaut J, Nikonov O, Petrenko A, Rüffer R, Spiering H, Szilágyi E. Coarsening of antiferromagnetic domains in multilayers: the key role of magnetocrystalline anisotropy. PHYSICAL REVIEW LETTERS 2002; 88:157202. [PMID: 11955216 DOI: 10.1103/physrevlett.88.157202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2001] [Indexed: 05/23/2023]
Abstract
The domain structure of an antiferromagnetic superlattice is studied. Synchrotron Mössbauer and polarized neutron reflectometric maps show micrometer-size primary domain formation as the external field decreases from saturation to remanence. A secondary domain state consisting mainly of at least 1 order of magnitude larger domains is created when a small field along the layer magnetizations induces a bulk-spin-flop transition. The domain-size distribution is reproducibly dependent on the magnetic prehistory. The condition for domain coarsening is shown to be the equilibrium of the external field energy with the anisotropy energy.
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Affiliation(s)
- D L Nagy
- KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest, Hungary
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