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Tong J, Feng Y, Tian F, Zhou L, Qin G, Zhang X. Unusual interfacial magnetic interactions for τ-MnAl with Fe(Co) atomic layers. Phys Chem Chem Phys 2019; 21:2443-2452. [PMID: 30652708 DOI: 10.1039/c8cp06599c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The interfacial magnetic interaction and coupling mechanism for τ-MnAl with Fe(Co) atomic layers have been studied using first principles calculations. The stable surface and interface were firstly determined by the surface energy of τ-MnAl and interface energy of τ-MnAl/Fe(Co) films, respectively. Their magnetic coupling interactions were investigated by varying the Fe(Co) atomic layer numbers. It is noted that both Fe and Co exhibited ferromagnetic coupling with τ-MnAl. Interestingly, an unusual oscillation phenomenon of magnetic coupling for τ-MnAl with Fe(Co) atomic layers was observed depending on the layer thickness of Fe(Co). Moreover, Fe and Co showed different oscillation modes. The energy difference between antiferromagnetic and ferromagnetic states is larger for τ-MnAl/Fe and τ-MnAl/Co when the Fe(Co) layer numbers are even and odd, respectively. Their mechanisms were analyzed based on the band structures and the confinement of electrons in quantum wells. It is found that the magnetic coupling oscillation in τ-MnAl/Fe originated from both the spin up Δ1 band and spin down Δ5 band at the [capital Gamma, Greek, macron] points. Comparatively, the oscillation of τ-MnAl/Co is due to the spin up band at the X[combining macron] point. The present results could provide insight to further understand interfacial exchange interactions among magnetic layers.
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Affiliation(s)
- Junwei Tong
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, China.
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2
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Manna S, Przybylski M, Sander D, Kirschner J. The role of electron confinement in Pd films for the oscillatory magnetic anisotropy in an adjacent Co layer. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:456001. [PMID: 27609044 DOI: 10.1088/0953-8984/28/45/456001] [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
We demonstrate the interplay between quantum well states in Pd and the magnetic anisotropy in Pd/Co/Cu (0 0 1) by combined scanning tunneling spectroscopy (STS) and magneto optical Kerr effect (MOKE) measurements. Low temperature scanning tunneling spectroscopy reveals occupied and unoccupied quantum well states (QWS) in atomically flat Pd films on Co/Cu (0 0 1). These states give rise to sharp peaks in the differential conductance spectra. A quantitative analysis of the spectra reveals the electronic dispersion of the Pd (0 0 1) d-band ([Formula: see text]-type) along the [Formula: see text]-X direction. In situ MOKE experiments on Pd/Co/Cu (1, 1, 13) uncover a periodic variation of the in-plane uniaxial magnetic anisotropy as a function of Pd thickness with a period of 6 atomic layers Pd. STS shows that QWS in Pd cross the Fermi level with the same periodicity of 6 atomic layers. Backed by previous theoretical work we ascribe the variation of the magnetic anisotropy in Co to QWS in the Pd overlayer. Our results suggest a novel venue towards tailoring uniaxial magnetic anisotropy of ferromagnetic films by exploiting QWS in an adjacent material with large spin-orbit coupling.
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Affiliation(s)
- Sujit Manna
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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3
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Chang CH, Dou KP, Chen YC, Hong TM, Kaun CC. Engineering the interlayer exchange coupling in magnetic trilayers. Sci Rep 2015; 5:16844. [PMID: 26596253 PMCID: PMC4657024 DOI: 10.1038/srep16844] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/21/2015] [Indexed: 12/01/2022] Open
Abstract
When the thickness of metal film approaches the nanoscale, itinerant carriers resonate between its boundaries and form quantum well states (QWSs), which are crucial to account for the film’s electrical, transport and magnetic properties. Besides the classic origin of particle-in-a-box, the QWSs are also susceptible to the crystal structures that affect the quantum resonance. Here we investigate the QWSs and the magnetic interlayer exchange coupling (IEC) in the Fe/Ag/Fe (001) trilayer from first-principles calculations. We find that the carriers at the Brillouin-zone center (belly) and edge (neck) separately form electron- and hole-like QWSs that give rise to an oscillatory feature for the IEC as a function of the Ag-layer thickness with long and short periods. Since the QWS formation sensitively depends on boundary conditions, one can switch between these two IEC periods by changing the Fe-layer thickness. These features, which also occur in the magnetic trilayers with other noble-metal spacers, open a new degree of freedom to engineer the IEC in magnetoresistance devices.
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Affiliation(s)
- Ching-Hao Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Kun-Peng Dou
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Ying-Chin Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Tzay-Ming Hong
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chao-Cheng Kaun
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.,Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
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Cao RX, Sun L, Miao BF, Li QL, Zheng C, Wu D, You B, Zhang W, Han P, Bader SD, Zhang WY, Ding HF. Spectroscopic study of Gd nanostructures quantum confined in Fe corrals. Sci Rep 2015; 5:12092. [PMID: 26160318 PMCID: PMC4498218 DOI: 10.1038/srep12092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/12/2015] [Indexed: 12/05/2022] Open
Abstract
Low dimensional nanostructures have attracted attention due to their rich physical properties and potential applications. The essential factor for their functionality is their electronic properties, which can be modified by quantum confinement. Here the electronic states of Gd atom trapped in open Fe corrals on Ag(111) were studied via scanning tunneling spectroscopy. A single spectroscopic peak above the Fermi level is observed after Gd adatoms are trapped inside Fe corrals, while two peaks appear in empty corrals. The single peak position is close to the higher energy peak of the empty corrals. These findings, attributed to quantum confinement of the corrals and Gd structures trapped inside, are supported by tight-binding calculations. This demonstrates and provides insights into atom trapping in open corrals of various diameters, giving an alternative approach to modify the properties of nano-objects.
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Affiliation(s)
- R X Cao
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China
| | - L Sun
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
| | - B F Miao
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China
| | - Q L Li
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China
| | - C Zheng
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China
| | - D Wu
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
| | - B You
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
| | - W Zhang
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
| | - P Han
- 1] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China [2] School of Electronic Science and Engineering, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China
| | - S D Bader
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - W Y Zhang
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
| | - H F Ding
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
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5
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Ma S, Tan A, Deng JX, Li J, Zhang ZD, Hwang C, Qiu ZQ. Tailoring the magnetic anisotropy of Py/Ni bilayer films using well aligned atomic steps on Cu(001). Sci Rep 2015; 5:11055. [PMID: 26067408 PMCID: PMC4464147 DOI: 10.1038/srep11055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/11/2015] [Indexed: 11/09/2022] Open
Abstract
Tailoring the spin orientation at the atomic scale has been a key task in spintronics technology. While controlling the out-of-plane to in-plane spin orientation has been achieved by a precise control of the perpendicular magnetic anisotropy at atomic layer thickness level, a design and control of the in-plane magnetic anisotropy has not yet been well developed. On well aligned atomic steps of a 6° vicinal Cu(001) surface with steps parallel to the [110] axis, we grow Py/Ni overlayer films epitaxially to permit a systematic exploration of the step-induced in-plane magnetic anisotropy as a function of both the Py and the Ni film thicknesses. We found that the atomic steps from the vicinal Cu(001) induce an in-plane uniaxial magnetic anisotropy that favors both Py and Ni magnetizations perpendicular to the steps, opposite to the behavior of Co on vicinal Cu(001). In addition, thickness-dependent study shows that the Ni films exhibit different magnetic anisotropy below and above ~6 ML Ni thickness.
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Affiliation(s)
- S Ma
- 1] Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China [2] Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - A Tan
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - J X Deng
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - J Li
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
| | - Z D Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - C Hwang
- Korea Research Institute of Standards and Science, Yuseong, Daejeon 305-340, Korea
| | - Z Q Qiu
- Department of Physics, University of California at Berkeley, Berkeley,California 94720
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Dąbrowski M, Peixoto TRF, Pazgan M, Winkelmann A, Cinal M, Nakagawa T, Takagi Y, Yokoyama T, Bisio F, Bauer U, Yildiz F, Przybylski M, Kirschner J. Oscillations of the orbital magnetic moment due to d-band quantum well states. PHYSICAL REVIEW LETTERS 2014; 113:067203. [PMID: 25148348 DOI: 10.1103/physrevlett.113.067203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Indexed: 06/03/2023]
Abstract
The effect of electron confinement on the magnetocrystalline anisotropy of ultrathin bcc Fe films is explored by combining photoemission spectroscopy, x-ray magnetic circular dichroism, and magneto-optical Kerr effect measurements. Pronounced thickness-dependent variations in the magnetocrystalline anisotropy are ascribed to periodic changes in the density of states at the Fermi level, induced by quantization of d(xz), d(yz) out-of-plane orbitals. Our results reveal a direct correlation between quantum well states, the orbital magnetic moment, and the magnetocrystalline anisotropy.
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Affiliation(s)
- M Dąbrowski
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - T R F Peixoto
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - M Pazgan
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - A Winkelmann
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - M Cinal
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - T Nakagawa
- Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585, Japan
| | - Y Takagi
- Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585, Japan
| | - T Yokoyama
- Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585, Japan
| | - F Bisio
- CNR-SPIN Corso Perrone 24, I-16152 Genova, Italy
| | - U Bauer
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - F Yildiz
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
| | - M Przybylski
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany and Faculty of Physics and Applied Computer Science, and Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, 30-059 Kraków, Poland
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany and Naturwissenschaftliche Fakultät II, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany
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Brovko OO, Ruiz-Díaz P, Dasa TR, Stepanyuk VS. Controlling magnetism on metal surfaces with non-magnetic means: electric fields and surface charging. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:093001. [PMID: 24523356 DOI: 10.1088/0953-8984/26/9/093001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We review the state of the art of surface magnetic property control with non-magnetic means, concentrating on metallic surfaces and techniques such as charge-doping or external electric field (EEF) application. Magneto-electric coupling via EEF-based charge manipulation is discussed as a way to tailor single adatom spins, exchange interaction between adsorbates or anisotropies of layered systems. The mechanisms of paramagnetic and spin-dependent electric field screening and the effect thereof on surface magnetism are discussed in the framework of theoretical and experimental studies. The possibility to enhance the effect of EEF by immersing the target system into an electrolyte or ionic liquid is discussed by the example of substitutional impurities and metallic alloy multilayers. A similar physics is pointed out for the case of charge traps, metallic systems decoupled from a bulk electron bath. In that case the charging provides the charge carrier density changes necessary to affect the magnetic moments and anisotropies in the system. Finally, the option of using quasi-free electrons rather than localized atomic spins for surface magnetism control is discussed with the example of Shockley-type metallic surface states confined to magnetic nanoislands.
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Affiliation(s)
- Oleg O Brovko
- Max-Planck Institut für Mikrostrukturphysik, Halle, Germany
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Li Y, Han W, Swartz AG, Pi K, Wong JJI, Mack S, Awschalom DD, Kawakami RK. Oscillatory spin polarization and magneto-optical Kerr effect in Fe₃O₄ thin films on GaAs(001). PHYSICAL REVIEW LETTERS 2010; 105:167203. [PMID: 21231004 DOI: 10.1103/physrevlett.105.167203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Indexed: 05/30/2023]
Abstract
The spin dependent properties of epitaxial Fe₃O₄ thin films on GaAs(001) are studied by the ferromagnetic proximity polarization (FPP) effect and magneto-optical Kerr effect (MOKE). Both FPP and MOKE show oscillations with respect to Fe₃O₄ film thickness, and the oscillations are large enough to induce repeated sign reversals. We attribute the oscillatory behavior to spin-polarized quantum well states forming in the Fe₃O₄ film. Quantum confinement of the t(2g) states near the Fermi level provides an explanation for the similar thickness dependences of the FPP and MOKE oscillations.
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Affiliation(s)
- Yan Li
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
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