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Varotto S, Cosset-Chéneau M, Grèzes C, Fu Y, Warin P, Brenac A, Jacquot JF, Gambarelli S, Rinaldi C, Baltz V, Attané JP, Vila L, Noël P. Independence of the Inverse Spin Hall Effect with the Magnetic Phase in Thin NiCu Films. PHYSICAL REVIEW LETTERS 2020; 125:267204. [PMID: 33449788 DOI: 10.1103/physrevlett.125.267204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/08/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
Large spin Hall angles have been observed in 3d ferromagnets, but their origin, and especially their link with the ferromagnetic order, remain unclear. Here, we investigate the evolution of the inverse spin Hall effect of Ni_{60}Cu_{40} and Ni_{50}Cu_{50} across their Curie temperatures using spin-pumping experiments. We show that the inverse spin Hall effect in these samples is comparable to that of platinum, and that it is insensitive to the magnetic order. These results point toward a Heisenberg localized model of the transition and suggest that the large spin Hall effects in 3d ferromagnets can be independent of the magnetic phase.
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Affiliation(s)
- Sara Varotto
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy
| | - Maxen Cosset-Chéneau
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Cécile Grèzes
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Yu Fu
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Patrick Warin
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Ariel Brenac
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | | | - Serge Gambarelli
- Université Grenoble Alpes, CEA, SYMMES, F-38000 Grenoble, France
| | | | - Vincent Baltz
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Jean-Philippe Attané
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Laurent Vila
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
| | - Paul Noël
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, F-38000 Grenoble, France
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Eich S, Plötzing M, Rollinger M, Emmerich S, Adam R, Chen C, Kapteyn HC, Murnane MM, Plucinski L, Steil D, Stadtmüller B, Cinchetti M, Aeschlimann M, Schneider CM, Mathias S. Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in cobalt. SCIENCE ADVANCES 2017; 3:e1602094. [PMID: 28378016 PMCID: PMC5365247 DOI: 10.1126/sciadv.1602094] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/09/2017] [Indexed: 05/29/2023]
Abstract
The evolution of the electronic band structure of the simple ferromagnets Fe, Co, and Ni during their well-known ferromagnetic-paramagnetic phase transition has been under debate for decades, with no clear and even contradicting experimental observations so far. Using time- and spin-resolved photoelectron spectroscopy, we can make a movie on how the electronic properties change in real time after excitation with an ultrashort laser pulse. This allows us to monitor large transient changes in the spin-resolved electronic band structure of cobalt for the first time. We show that the loss of magnetization is not only found around the Fermi level, where the states are affected by the laser excitation, but also reaches much deeper into the electronic bands. We find that the ferromagnetic-paramagnetic phase transition cannot be explained by a loss of the exchange splitting of the spin-polarized bands but instead shows rapid band mirroring after the excitation, which is a clear signature of extremely efficient ultrafast magnon generation. Our result helps to understand band structure formation in these seemingly simple ferromagnetic systems and gives first clear evidence of the transient processes relevant to femtosecond demagnetization.
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Affiliation(s)
- Steffen Eich
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - Moritz Plötzing
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI 6), 52425 Jülich, Germany
- Experimentalphysik Universität Duisburg-Essen, Lotharstraße 1, 47057 Duisburg,Germany
| | - Markus Rollinger
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - Sebastian Emmerich
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
- Graduate School MAINZ, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern, Germany
| | - Roman Adam
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI 6), 52425 Jülich, Germany
| | - Cong Chen
- JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309–0440, USA
| | - Henry Cornelius Kapteyn
- JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309–0440, USA
| | - Margaret M. Murnane
- JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309–0440, USA
| | - Lukasz Plucinski
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI 6), 52425 Jülich, Germany
- Experimentalphysik Universität Duisburg-Essen, Lotharstraße 1, 47057 Duisburg,Germany
| | - Daniel Steil
- Georg-August-Universität Göttingen, I. Physikalisches Institut, 37077 Göttingen, Germany
| | - Benjamin Stadtmüller
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
- Graduate School MAINZ, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern, Germany
| | - Mirko Cinchetti
- Experimentelle Physik VI, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Martin Aeschlimann
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - Claus M. Schneider
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI 6), 52425 Jülich, Germany
- Experimentalphysik Universität Duisburg-Essen, Lotharstraße 1, 47057 Duisburg,Germany
| | - Stefan Mathias
- Georg-August-Universität Göttingen, I. Physikalisches Institut, 37077 Göttingen, Germany
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Andres B, Weiss P, Wietstruk M, Weinelt M. Spin-dependent lifetime and exchange splitting of surface states on Ni(1 1 1). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:015503. [PMID: 25469618 DOI: 10.1088/0953-8984/27/1/015503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report on a spin-resolved two-photon photoemission study of the Ni(1 1 1) surface states. Nickel thin films were grown by molecular beam epitaxy on a W(1 1 0) substrate. The first image-potential state is used as a sensor to map the spin polarization of the occupied surface states. This allows us to identify the majority spin component of the Shockley surface state as well as a majority and minority d-derived surface resonance. The n = 1 image-potential state is found to be exchange split by 14 ± 3 meV. In spite of the fact that the band structure at the Fermi level exhibits a strongly discerned density of states in both spin channels, we observe low spin asymmetries in the decay and dephasing rates of the photoexcited electrons. Varying the sample preparation reveals that the Shockley surface state contributes about 40% to the spin-dependent decay rate.
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Affiliation(s)
- Beatrice Andres
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
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Jeong DW, Choi HC, Kim CH, Chang SH, Sohn CH, Park HJ, Kang TD, Cho DY, Baek SH, Eom CB, Shim JH, Yu J, Kim KW, Moon SJ, Noh TW. Temperature evolution of itinerant ferromagnetism in SrRuO3 probed by optical spectroscopy. PHYSICAL REVIEW LETTERS 2013; 110:247202. [PMID: 25165956 DOI: 10.1103/physrevlett.110.247202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 06/03/2023]
Abstract
The temperature (T) dependence of the optical conductivity spectra σ(ω) of a single crystal SrRuO(3) thin film is studied over a T range from 5 to 450 K. We observed significant T dependence of the spectral weights of the charge transfer and interband d-d transitions across the ferromagnetic Curie temperature (T(c) ∼ 150 K). Such T dependence was attributed to the increase in the Ru spin moment, which is consistent with the results of density functional theory calculations. T scans of σ(Ω,T) at fixed frequencies Ω reveal a clear T(2) dependence below T(c), demonstrating that the Stoner mechanism is involved in the evolution of the electronic structure. In addition, σ(Ω,T) continues to evolve at temperatures above T(c), indicating that the local spin moment persists in the paramagnetic state. This suggests that SrRuO(3) is an intriguing oxide system with itinerant ferromagnetism.
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Affiliation(s)
- D W Jeong
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Hong Chul Choi
- Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Choong H Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Seo Hyoung Chang
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - C H Sohn
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - H J Park
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - T D Kang
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Deok-Yong Cho
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - S H Baek
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C B Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J H Shim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea and Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J Yu
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - K W Kim
- Department of Physics, Chungbuk National University, Cheongju 361-763, Korea
| | - S J Moon
- Department of Physics, Hanyang University, Seoul 133-791, Korea
| | - T W Noh
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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Klebanoff L, Van Campen D, Pouliot R. Spin-Resolved Photoemission Study of n = 2 Core Levels of Iron. ACTA ACUST UNITED AC 2012. [DOI: 10.1557/proc-313-589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe first spin-resolved x-ray photoelectron spectroscopy (SRXPS) study of the n = 2 core levels of ferromagnetic Fe are reported. The 2p3/2, 2p1/2 and 2s core levels all display interesting spin-dependent structures and splittings. The spectral complexity predicted by a purely atomic picture is not observed in the data. The results indicate that theories incorporating the delocalization of the 3d valence band are more applicable to the description of core-level photoemission in iron.
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Pickel M, Schmidt AB, Weinelt M, Donath M. Magnetic exchange splitting in Fe above the Curie temperature. PHYSICAL REVIEW LETTERS 2010; 104:237204. [PMID: 20867266 DOI: 10.1103/physrevlett.104.237204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/03/2010] [Indexed: 05/29/2023]
Abstract
The magnetic exchange splitting of electronic states in a 7 monolayer Fe film on Cu(001) was investigated below and above the Curie temperature T(C), using image-potential surface states as sensor. At T(C), the long-range magnetic order breaks down as reflected by a vanishing spin splitting and vanishing spin polarization. The exchange splitting, in contrast, does not change abruptly at T(C) but persists up to T=1.2T(C). Equally, the spin-integrated linewidth shows no signature of the magnetic phase transition but smoothly decreases with increasing temperature. Our experimental results confirm theoretical expectations that, at T(C), the long-range magnetic order disappears but the local magnetic moments and, in particular, the valence electronic structure are unaffected by the phase transition.
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Affiliation(s)
- M Pickel
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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On the Way to a Gutzwiller Density Functional Theory. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/3-540-44610-9_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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8
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Donath M, Dose V. Unbiased access to exchange splitting of magnetic bands using the maximum entropy method. PHYSICAL REVIEW LETTERS 1993; 71:899-902. [PMID: 10055396 DOI: 10.1103/physrevlett.71.899] [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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9
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Braun J, Borstel G, Nolting W. Theory of temperature-dependent photoemission in 3d-band ferromagnets: Application to Ni(110) and Ni(111). PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:3510-3519. [PMID: 10004068 DOI: 10.1103/physrevb.46.3510] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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10
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Nolting W, Geipel G, Ertl K. Theory of Auger-electron and appearance-potential spectroscopy for interacting valence-band electrons. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:12197-12215. [PMID: 9999376 DOI: 10.1103/physrevb.44.12197] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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