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Lo Conte R, Nandy AK, Chen G, Fernandes Cauduro AL, Maity A, Ophus C, Chen Z, N'Diaye AT, Liu K, Schmid AK, Wiesendanger R. Tuning the Properties of Zero-Field Room Temperature Ferromagnetic Skyrmions by Interlayer Exchange Coupling. NANO LETTERS 2020; 20:4739-4747. [PMID: 32459968 DOI: 10.1021/acs.nanolett.0c00137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Magnetic materials offer an opportunity to overcome the scalability and energy consumption limits affecting the semiconductor industry. New computational device architectures, such as low-power solid state magnetic logic and memory-in-logic devices, have been proposed which rely on the unique properties of magnetic materials. Magnetic skyrmions, topologically protected quasi-particles, are at the core of many of the newly proposed spintronic devices. Many different materials systems have been shown hosting ferromagnetic skyrmions at room temperature. However, a magnetic field is a key ingredient to stabilize skyrmions, and this is not desirable for applications, due to the poor scalability of active components generating magnetic fields. Here we report the observation of ferromagnetic skyrmions at room temperature and zero magnetic field, stabilized through interlayer exchange coupling (IEC) between a reference magnet and a free magnet. Most importantly, by tuning the strength of the IEC, we are able to tune the skyrmion size and areal density. Our findings are relevant to the development of skyrmion-based spintronic devices suitable for general-use applications which go beyond modern nanoelectronics.
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Affiliation(s)
- Roberto Lo Conte
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
- Department of Physics, University of Hamburg, D-20355 Hamburg, Germany
| | - Ashis K Nandy
- School of Physical Sciences, National Institute of Science Education and Research, HBNI, P.O. Jatni, 752050, Jatni, India
| | - Gong Chen
- Department of Physics, University of California, Davis, California 95616, United States
| | - Andre L Fernandes Cauduro
- National Center for Electron Microscopy, Molecular Foundry - Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ajanta Maity
- School of Physical Sciences, National Institute of Science Education and Research, HBNI, P.O. Jatni, 752050, Jatni, India
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry - Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Zhijie Chen
- Physics Department, Georgetown University, Washington, DC 20057, United States
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kai Liu
- Department of Physics, University of California, Davis, California 95616, United States
- Physics Department, Georgetown University, Washington, DC 20057, United States
| | - Andreas K Schmid
- National Center for Electron Microscopy, Molecular Foundry - Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Shalygina E, Kharlamova A, Makarov A, Kurlyandskaya G, Svalov A. Structural and magnetic characteristics of the Co/Cu/Co thin-film systems. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201818503009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The results on investigation of structural and magnetic characteristics of Co/Cu/Co thin-film systems obtained by magnetron sputtering on glass substrates are presented. The thickness of Co layers in all samples is equal to 5 nm and the Cu layer is varied from 0.5 to 4 nm. It is found that the saturation field, HS, oscillates in magnitude with increasing Cu layer thickness with the period of the order of 1 nm. The maximum values of HS are observed for tCu = 1.4, 2.2 and 3.2 nm. The hysteresis loops measured for these samples in a magnetic field applied along the easy magnetization axis have a two-step form, and for other tCu – rectangular one. The obtained results are explained by the presence of exchange coupling between the ferromagnetic layers through a Co spacer and its oscillating behavior with changing tCu.
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Chen B, Xu H, Ma C, Mattauch S, Lan D, Jin F, Guo Z, Wan S, Chen P, Gao G, Chen F, Su Y, Wu W. All-oxide–based synthetic antiferromagnets exhibiting layer-resolved magnetization reversal. Science 2017; 357:191-194. [DOI: 10.1126/science.aak9717] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 06/07/2017] [Indexed: 11/02/2022]
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Zhang B, Wu CB, Kuch W. Tailoring interlayer coupling and coercivity in Co/Mn/Co trilayers by controlling the interface roughness. JOURNAL OF APPLIED PHYSICS 2014; 115. [DOI: 10.1063/1.4884235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Epitaxial Co/Mn/Co trilayers with a wedged Mn layer were grown on Cu(001) and studied by magneto-optical Kerr effect measurements. The bottom Co film as well as the Mn film exhibits a layer-by-layer growth mode, which allows to modify both interface roughnesses on the atomic scale by tuning the thicknesses of the films to achieve a certain filling of their topmost atomic layers. The onset of antiferromagnetic order in the Mn layer at room temperature was found at thicknesses of 4.1 (4.8) and 3.4 (4.0) atomic monolayers (ML) for a filled (half-filled) topmost atomic layer of the bottom Co film in Mn/Co bilayers and Co/Mn/Co trilayers, respectively. Magnetization loops with only one step were found for a trilayer with half-filled topmost atomic layer of the bottom Co film, while loops with two separate steps have been observed in trilayers with an integer number of atomic layers in the bottom Co film. The coercivity of the top Co film shows an oscillation with 1 ML period as a function of the Mn thickness above 10 ML, which is interpreted as the influence of the atomic-scale control of the interface roughness on the interface exchange coupling between the antiferromagnetic Mn and the top ferromagnetic (FM) Co layer. The strength of the magnetic interlayer coupling between the top and bottom Co layers through the Mn layer for an integer number of atomic layers in the bottom Co layer, deduced from minor-loop measurements, exhibits an oscillation with a period of 2 ML Mn thickness, indicative of direct exchange coupling through the antiferromagnetic Mn layer. In addition, a long-period interlayer coupling of the two FM layers with antiparallel coupling maxima at Mn thicknesses of 2.5, 8.2, and 13.7 ML is observed and attributed to indirect exchange coupling of the Rudermann-Kittel-Kasuya-Yosida type.
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Affiliation(s)
| | | | - Wolfgang Kuch
- Freie Universität Berlin Institut für Experimentalphysik, , Arnimallee 14, 14195 Berlin, Germany
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Lin MK, Nakayama Y, Chen CH, Wang CY, Jeng HT, Pi TW, Ishii H, Tang SJ. Tuning gap states at organic-metal interfaces via quantum size effects. Nat Commun 2013; 4:2925. [DOI: 10.1038/ncomms3925] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/12/2013] [Indexed: 01/06/2023] Open
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Won C, Wu YZ, Arenholz E, Choi J, Wu J, Qiu ZQ. Symmetry-breaking induced exchange bias in ferromagnetic Ni-Cu-Co and Ni-Fe-Co sandwiches grown on a vicinal Cu(001) surface. PHYSICAL REVIEW LETTERS 2007; 99:077203. [PMID: 17930921 DOI: 10.1103/physrevlett.99.077203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Indexed: 05/25/2023]
Abstract
Ferromagnetic Ni-Cu-Co and Ni-Fe-Co sandwiches were grown epitaxially onto a vicinal Cu(001) substrate and investigated using magneto-optical Kerr effect and x-ray magnetic circular dichroism techniques. We find that the atomic steps of the vicinal surface break the magnetic reversal symmetry to induce an exchange bias in the Ni perpendicular magnetic hysteresis loop. The Ni exchange bias direction can be switched by changing the direction of the in-plane Co magnetization. In addition, the exchange bias can be tailored by changing the Cu or Fe spacer layer thickness.
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Affiliation(s)
- C Won
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
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Rh electrodeposition on Pt in acidic medium: a study using cyclic voltammetry and an electrochemical quartz crystal microbalance. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2004.03.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chapter 1 Interlayer exchange coupling in layered magnetic structures. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1567-2719(01)13005-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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9
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Würsch C, Stamm C, Egger S, Pescia D, Baltensperger W, Helman JS. Quantum oscillations in a confined electron gas. Nature 1997. [DOI: 10.1038/40081] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Huang DJ, Johnson PD, Shi X. Quantum-well states and the short period of oscillation in Cu/Co(001) multilayers. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:17123-17127. [PMID: 9985847 DOI: 10.1103/physrevb.54.17123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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11
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Lee B, Chang YC. Effects of Fano resonances on the interlayer coupling in magnetic multilayers. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:13034-13041. [PMID: 9985163 DOI: 10.1103/physrevb.54.13034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Segovia P, Michel EG, Ortega JE. Quantum Well States and Short Period Oscillations of the Density of States at the Fermi Level in Cu Films Grown on fcc Co(100). PHYSICAL REVIEW LETTERS 1996; 77:3455-3458. [PMID: 10062224 DOI: 10.1103/physrevlett.77.3455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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13
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Lang P, Nordström L, Wildberger K, Zeller R, Dederichs PH, Hoshino T. Ab initio calculations of interaction energies of magnetic layers in noble metals: Co/Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:9092-9107. [PMID: 9982410 DOI: 10.1103/physrevb.53.9092] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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14
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Lee B, Chang YC. Effects of realistic band structures on the interlayer coupling strengths in magnetic multilayers. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:3499-3510. [PMID: 9981473 DOI: 10.1103/physrevb.52.3499] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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15
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Bruno P. Theory of interlayer magnetic coupling. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:411-439. [PMID: 9979618 DOI: 10.1103/physrevb.52.411] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Li D, Pearson J, Mattson JE, Bader SD, Johnson PD. Photoemission study of quantum confinement by a finite barrier: Cu/Co(wedge)/Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:7195-7199. [PMID: 9977282 DOI: 10.1103/physrevb.51.7195] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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17
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Brookes NB, Chang Y, Johnson PD. Ag/Fe(001) interface. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:15330-15336. [PMID: 9975885 DOI: 10.1103/physrevb.50.15330] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Nordström L, Lang P, Zeller R, Dederichs PH. Influence of the magnetic-layer thickness on the interlayer exchange coupling: Competition between oscillation periods. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:13058-13061. [PMID: 9975491 DOI: 10.1103/physrevb.50.13058] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Johnson PD, Garrison K, Dong Q, Smith NV, Li D, Mattson J, Pearson J, Bader SD. Hybridization and the effective mass of quantum-well states in magnetic multilayers. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:8954-8956. [PMID: 9974936 DOI: 10.1103/physrevb.50.8954] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Pérez-Díaz JL, Muñoz MC. Spin-polarized electrons at interfaces: Co/Cu systems. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:8824-8831. [PMID: 9974903 DOI: 10.1103/physrevb.50.8824] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Modak AR, Smith DJ, Parkin SS. Dependence of giant magnetoresistance on grain size in Co/Cu multilayers. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:4232-4235. [PMID: 9976717 DOI: 10.1103/physrevb.50.4232] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Koelling DD. Magnetic multilayers with (Nb,Mo,Cr) spacer materials. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:273-290. [PMID: 9974541 DOI: 10.1103/physrevb.50.273] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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23
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Parkin SS, Farrow RF, Marks RF, Cebollada A, Harp GR, Savoy RJ. Oscillations of interlayer exchange coupling and giant magnetoresistance in (111) oriented permalloy/Au multilayers. PHYSICAL REVIEW LETTERS 1994; 72:3718-3721. [PMID: 10056272 DOI: 10.1103/physrevlett.72.3718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Shi ZP, Levy PM, Fry JL. Interlayer magnetic coupling in metallic multilayer structures. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:15159-15178. [PMID: 10010623 DOI: 10.1103/physrevb.49.15159] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Muñoz MC, Pérez-Diaz JL. Exchange coupling in magnetic multilayers: A quantum-size effect. PHYSICAL REVIEW LETTERS 1994; 72:2482-2485. [PMID: 10055891 DOI: 10.1103/physrevlett.72.2482] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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26
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Lee B, Chang YC. Complex-band method for calculating the Ruderman-Kittel-Kasuya-Yosida interaction in magnetic superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:8868-8881. [PMID: 10009670 DOI: 10.1103/physrevb.49.8868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Okuno SN, Inomata K. Two oscillatory behaviors as functions of ferromagnetic layer thickness in Fe/Cr(100) multilayers. PHYSICAL REVIEW LETTERS 1994; 72:1553-1556. [PMID: 10055638 DOI: 10.1103/physrevlett.72.1553] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Bloemen PJ, Johnson MT, Coehoorn R, Jungblut R, Reinders A. Magnetic layer thickness dependence of the interlayer exchange coupling in (001) Co/Cu/Co. PHYSICAL REVIEW LETTERS 1994; 72:764-767. [PMID: 10056517 DOI: 10.1103/physrevlett.72.764] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Fullerton EE, Conover MJ, Mattson JE, Sowers CH, Bader SD. Oscillatory interlayer coupling and giant magnetoresistance in epitaxial Fe/Cr(211) and (100) superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:15755-15763. [PMID: 10008128 DOI: 10.1103/physrevb.48.15755] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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30
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Garrison K, Chang Y, Johnson PD. Spin polarization of quantum well states in copper thin films deposited on a Co(001) substrate. PHYSICAL REVIEW LETTERS 1993; 71:2801-2804. [PMID: 10054779 DOI: 10.1103/physrevlett.71.2801] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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31
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Carbone C, Vescovo E, Rader O, Gudat W, Eberhardt W. Exchange split quantum well states of a noble metal film on a magnetic substrate. PHYSICAL REVIEW LETTERS 1993; 71:2805-2808. [PMID: 10054780 DOI: 10.1103/physrevlett.71.2805] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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32
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Mankey GJ, Willis RF, Himpsel FJ. Band structure of the magnetic fcc pseudomorphs: Ni(100), Co(100), and Fe(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:10284-10291. [PMID: 10007306 DOI: 10.1103/physrevb.48.10284] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Lang P, Nordström L, Zeller R, Dederichs PH. Ab initio calculations of the exchange coupling of Fe and Co monolayers in Cu. PHYSICAL REVIEW LETTERS 1993; 71:1927-1930. [PMID: 10054535 DOI: 10.1103/physrevlett.71.1927] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Stiles MD. Exchange coupling in magnetic heterostructures. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:7238-7258. [PMID: 10006893 DOI: 10.1103/physrevb.48.7238] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bruno E, Gyorffy BL. Geometrical resonance in magnetic multilayers. PHYSICAL REVIEW LETTERS 1993; 71:181-184. [PMID: 10054403 DOI: 10.1103/physrevlett.71.181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Okuno SN, Inomata K. Dependence on Fermi surface dimensions of oscillatory exchange coupling in Co/Cu1-xNix(110) multilayers. PHYSICAL REVIEW LETTERS 1993; 70:1711-1714. [PMID: 10053365 DOI: 10.1103/physrevlett.70.1711] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Ortega JE, Himpsel FJ, Mankey GJ, Willis RF. Quantum-well states and magnetic coupling between ferromagnets through a noble-metal layer. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:1540-1552. [PMID: 10006170 DOI: 10.1103/physrevb.47.1540] [Citation(s) in RCA: 220] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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