1
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Bobowski K, Zheng X, Frietsch B, Lawrenz D, Bronsch W, Gahl C, Andres B, Strüber C, Carley R, Teichmann M, Scherz A, Molodtsov S, Cacho C, Chapman RT, Springate E, Weinelt M. Ultrafast spin transfer and its impact on the electronic structure. SCIENCE ADVANCES 2024; 10:eadn4613. [PMID: 39018415 PMCID: PMC466954 DOI: 10.1126/sciadv.adn4613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 06/12/2024] [Indexed: 07/19/2024]
Abstract
Optically induced intersite spin transfer (OISTR) promises manipulation of spin systems within the ultimate time limit of laser excitation. Following its prediction, signatures of ultrafast spin transfer between oppositely aligned spin sublattices have been observed in magnetic alloys and multilayers. However, it is known neither from theory nor from experiment whether the band structure immediately follows the ultrafast change in spin polarization or whether the exchange split bands remain rigid. We show that ultrafast spin transfer occurs even in ferromagnetic gadolinium metal. Charge transfer between localized surface and extended valence-band states leads to a decrease of the surface spin polarization. This synchronously alters the exchange splitting of the bulk valence bands during laser excitation. Moreover, the onset of demagnetization can be tuned by over 200 fs by changing the temperature-dependent spin mixing. Our results show a promising route to ultrafast control of the magnetization, widening the impact and applicability of OISTR.
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Affiliation(s)
- Kamil Bobowski
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Xinwei Zheng
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Björn Frietsch
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Dominic Lawrenz
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Wibke Bronsch
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
| | - Cornelius Gahl
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Beatrice Andres
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Christian Strüber
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Robert Carley
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Andreas Scherz
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Serguei Molodtsov
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
- Institute of Experimental Physics, TU Bergakademie Freiberg, Leipziger Str. 23, 09599 Freiberg, Germany
| | | | | | | | - Martin Weinelt
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
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2
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Thielemann-Kühn N, Amrhein T, Bronsch W, Jana S, Pontius N, Engel RY, Miedema PS, Legut D, Carva K, Atxitia U, van Kuiken BE, Teichmann M, Carley RE, Mercadier L, Yaroslavtsev A, Mercurio G, Le Guyader L, Agarwal N, Gort R, Scherz A, Dziarzhytski S, Brenner G, Pressacco F, Wang RP, Schunck JO, Sinha M, Beye M, Chiuzbăian GS, Oppeneer PM, Weinelt M, Schüßler-Langeheine C. Optical control of 4 f orbital state in rare-earth metals. SCIENCE ADVANCES 2024; 10:eadk9522. [PMID: 38630818 PMCID: PMC11023516 DOI: 10.1126/sciadv.adk9522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024]
Abstract
A change of orbital state alters the coupling between ions and their surroundings drastically. Orbital excitations are hence key to understand and control interaction of ions. Rare-earth elements with strong magneto-crystalline anisotropy (MCA) are important ingredients for magnetic devices. Thus, control of their localized 4f magnetic moments and anisotropy is one major challenge in ultrafast spin physics. With time-resolved x-ray absorption and resonant inelastic scattering experiments, we show for Tb metal that 4f-electronic excitations out of the ground-state multiplet occur after optical pumping. These excitations are driven by inelastic 5d-4f-electron scattering, altering the 4f-orbital state and consequently the MCA with important implications for magnetization dynamics in 4f-metals and more general for the excitation of localized electronic states in correlated materials.
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Affiliation(s)
- Nele Thielemann-Kühn
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Tim Amrhein
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Wibke Bronsch
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
- Elettra-Sincrotrone Trieste S.C.p.A., Strada statale 14 – km 163,5, 34149 Basovizza, Trieste, Italy
| | - Somnath Jana
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Niko Pontius
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Robin Y. Engel
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Piter S. Miedema
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Dominik Legut
- VSB - Technical University Ostrava, IT4Innovations, 708 00 Ostrava, Czech Republic
- Charles University, Faculty of Mathematics and Physics, DCMP, 12116 Prague 2, Czech Republic
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, CZ-121 16 Prague, Czech Republic
| | - Karel Carva
- Charles University, Faculty of Mathematics and Physics, DCMP, 12116 Prague 2, Czech Republic
| | - Unai Atxitia
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
| | | | | | | | | | - Alexander Yaroslavtsev
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 75120 Uppsala, Sweden
| | | | | | - Naman Agarwal
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Rafael Gort
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Andres Scherz
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Günter Brenner
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Federico Pressacco
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Ru-Pan Wang
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Universität Hamburg, Physics Department, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Jan O. Schunck
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Universität Hamburg, Physics Department, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Mangalika Sinha
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Martin Beye
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Gheorghe S. Chiuzbăian
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement,75005 Paris, France
| | - Peter M. Oppeneer
- Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 75120 Uppsala, Sweden
| | - Martin Weinelt
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
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3
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Mattern M, Pudell JE, Dumesnil K, von Reppert A, Bargheer M. Towards shaping picosecond strain pulses via magnetostrictive transducers. PHOTOACOUSTICS 2023; 30:100463. [PMID: 36874592 PMCID: PMC9982602 DOI: 10.1016/j.pacs.2023.100463] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 06/07/2023]
Abstract
Using time-resolved x-ray diffraction, we demonstrate the manipulation of the picosecond strain response of a metallic heterostructure consisting of a dysprosium (Dy) transducer and a niobium (Nb) detection layer by an external magnetic field. We utilize the first-order ferromagnetic-antiferromagnetic phase transition of the Dy layer, which provides an additional large contractive stress upon laser excitation compared to its zero-field response. This enhances the laser-induced contraction of the transducer and changes the shape of the picosecond strain pulses driven in Dy and detected within the buried Nb layer. Based on our experiment with rare-earth metals we discuss required properties for functional transducers, which may allow for novel field-control of the emitted picosecond strain pulses.
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Affiliation(s)
- Maximilian Mattern
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
| | - Jan-Etienne Pudell
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
- European XFEL, 22869 Schenefeld, Germany
| | - Karine Dumesnil
- Institut Jean Lamour (UMR CNRS 7198), Université Lorraine, 54000 Nancy, France
| | | | - Matias Bargheer
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
- Helmholtz Zentrum Berlin, 12489 Berlin, Germany
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4
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Windsor YW, Lee SE, Zahn D, Borisov V, Thonig D, Kliemt K, Ernst A, Schüßler-Langeheine C, Pontius N, Staub U, Krellner C, Vyalikh DV, Eriksson O, Rettig L. Exchange scaling of ultrafast angular momentum transfer in 4f antiferromagnets. NATURE MATERIALS 2022; 21:514-517. [PMID: 35210586 PMCID: PMC9064787 DOI: 10.1038/s41563-022-01206-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Ultrafast manipulation of magnetism bears great potential for future information technologies. While demagnetization in ferromagnets is governed by the dissipation of angular momentum1-3, materials with multiple spin sublattices, for example antiferromagnets, can allow direct angular momentum transfer between opposing spins, promising faster functionality. In lanthanides, 4f magnetic exchange is mediated indirectly through the conduction electrons4 (the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction), and the effect of such conditions on direct spin transfer processes is largely unexplored. Here, we investigate ultrafast magnetization dynamics in 4f antiferromagnets and systematically vary the 4f occupation, thereby altering the magnitude of the RKKY coupling energy. By combining time-resolved soft X-ray diffraction with ab initio calculations, we find that the rate of direct transfer between opposing moments is directly determined by this coupling. Given the high sensitivity of RKKY to the conduction electrons, our results offer a useful approach for fine tuning the speed of magnetic devices.
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Affiliation(s)
- Y W Windsor
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Berlin, Germany.
| | - S-E Lee
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Berlin, Germany
| | - D Zahn
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Berlin, Germany
| | - V Borisov
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - D Thonig
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
- School of Science and Technology, Örebro University, Örebro, Sweden
| | - K Kliemt
- Physikalisches Institut, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - A Ernst
- Institute for Theoretical Physics, Johannes Kepler University, Linz, Austria
- Max-Planck-Institut für Mikrostrukturphysik, Halle (Saale), Germany
| | | | - N Pontius
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - C Krellner
- Physikalisches Institut, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - O Eriksson
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
- School of Science and Technology, Örebro University, Örebro, Sweden
| | - L Rettig
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Berlin, Germany.
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5
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Tauchert SR, Volkov M, Ehberger D, Kazenwadel D, Evers M, Lange H, Donges A, Book A, Kreuzpaintner W, Nowak U, Baum P. Polarized phonons carry angular momentum in ultrafast demagnetization. Nature 2022; 602:73-77. [PMID: 35110761 DOI: 10.1038/s41586-021-04306-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 12/01/2021] [Indexed: 11/10/2022]
Abstract
Magnetic phenomena are ubiquitous in nature and indispensable for modern science and technology, but it is notoriously difficult to change the magnetic order of a material in a rapid way. However, if a thin nickel film is subjected to ultrashort laser pulses, it loses its magnetic order almost completely within femtosecond timescales1. This phenomenon is widespread2-7 and offers opportunities for rapid information processing8-11 or ultrafast spintronics at frequencies approaching those of light8,9,12. Consequently, the physics of ultrafast demagnetization is central to modern materials research1-7,13-28, but a crucial question has remained elusive: if a material loses its magnetization within mere femtoseconds, where is the missing angular momentum in such a short time? Here we use ultrafast electron diffraction to reveal in nickel an almost instantaneous, long-lasting, non-equilibrium population of anisotropic high-frequency phonons that appear within 150-750 fs. The anisotropy plane is perpendicular to the direction of the initial magnetization and the atomic oscillation amplitude is 2 pm. We explain these observations by means of circularly polarized phonons that quickly absorb the angular momentum of the spin system before macroscopic sample rotation. The time that is needed for demagnetization is related to the time it takes to accelerate the atoms. These results provide an atomistic picture of the Einstein-de Haas effect and signify the general importance of polarized phonons for non-equilibrium dynamics and phase transitions.
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Affiliation(s)
- S R Tauchert
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany.,Ludwig-Maximilians-Universität München, Garching, Germany
| | - M Volkov
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany.,Ludwig-Maximilians-Universität München, Garching, Germany
| | - D Ehberger
- Ludwig-Maximilians-Universität München, Garching, Germany
| | - D Kazenwadel
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - M Evers
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - H Lange
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - A Donges
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - A Book
- Technische Universität München, Physik-Department E21, Garching, Germany
| | - W Kreuzpaintner
- Technische Universität München, Physik-Department E21, Garching, Germany.,Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing, China.,Spallation Neutron Source Science Center, Dongguan, China
| | - U Nowak
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - P Baum
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany. .,Ludwig-Maximilians-Universität München, Garching, Germany.
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6
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Kim SK, Beach GSD, Lee KJ, Ono T, Rasing T, Yang H. Ferrimagnetic spintronics. NATURE MATERIALS 2022; 21:24-34. [PMID: 34949868 DOI: 10.1038/s41563-021-01139-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 09/21/2021] [Indexed: 06/14/2023]
Abstract
Ferrimagnets composed of multiple and antiferromagnetically coupled magnetic elements have attracted much attention recently as a material platform for spintronics. They offer the combined advantages of both ferromagnets and antiferromagnets, namely the easy control and detection of their net magnetization by an external field, antiferromagnetic-like dynamics faster than ferromagnetic dynamics and the potential for high-density devices. This Review summarizes recent progress in ferrimagnetic spintronics, with particular attention to the most-promising functionalities of ferrimagnets, which include their spin transport, spin texture dynamics and all-optical switching.
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Affiliation(s)
- Se Kwon Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
- Department of Materials Science and Engineering, Korea University, Seoul, Korea.
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea.
| | - Teruo Ono
- Institute of Chemical Research, Kyoto University, Kyoto, Japan
- Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Theo Rasing
- Institute for Molecules and Materials, Radboud University, Nijmegen, the Netherlands
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
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7
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Eschenlohr A. Spin dynamics at interfaces on femtosecond timescales. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:013001. [PMID: 33034305 DOI: 10.1088/1361-648x/abb519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The excitation of magnetically ordered materials with ultrashort laser pulses results in magnetization dynamics on femto- to picosecond timescales. These non-equilibrium spin dynamics have emerged as a rapidly developing research field in recent years. Unraveling the fundamental microscopic processes in the interaction of ultrashort optical pulses with the charge, spin, orbital, and lattice degrees of freedom in magnetic materials shows the potential for controlling spin dynamics on their intrinsic timescales and thereby bring spintronics applications into the femtosecond range. In particular, femtosecond spin currents offer fascinating new possibilities to manipulate magnetization in an ultrafast and non-local manner, via spin injection and spin transfer torque at the interfaces of ferromagnetic layered structures. This topical review covers recent progress on spin dynamics at interfaces on femtosecond time scales. The development of the field of ultrafast spin dynamics in ferromagnetic heterostructures will be reviewed, starting from spin currents propagating on nanometer length scales through layered structures before focusing on femtosecond spin transfer at interfaces. The properties of these ultrafast spin-dependent charge currents will be discussed, as well as the materials dependence of femtosecond spin injection, the role of the interface properties, and competing microscopic processes leading to a loss of spin polarization on sub-picosecond timescales.
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Affiliation(s)
- A Eschenlohr
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany
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8
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Frietsch B, Donges A, Carley R, Teichmann M, Bowlan J, Döbrich K, Carva K, Legut D, Oppeneer PM, Nowak U, Weinelt M. The role of ultrafast magnon generation in the magnetization dynamics of rare-earth metals. SCIENCE ADVANCES 2020; 6:6/39/eabb1601. [PMID: 32967827 PMCID: PMC7531875 DOI: 10.1126/sciadv.abb1601] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 06/25/2020] [Indexed: 05/29/2023]
Abstract
Ultrafast demagnetization of rare-earth metals is distinct from that of 3d ferromagnets, as rare-earth magnetism is dominated by localized 4f electrons that cannot be directly excited by an optical laser pulse. Their demagnetization must involve excitation of magnons, driven either through exchange coupling between the 5d6s-itinerant and 4f-localized electrons or by coupling of 4f spins to lattice excitations. Here, we disentangle the ultrafast dynamics of 5d6s and 4f magnetic moments in terbium metal by time-resolved photoemission spectroscopy. We show that the demagnetization time of the Tb 4f magnetic moments of 400 fs is set by 4f spin-lattice coupling. This is experimentally evidenced by a comparison to ferromagnetic gadolinium and supported by orbital-resolved spin dynamics simulations. Our findings establish coupling of the 4f spins to the lattice via the orbital momentum as an essential mechanism driving magnetization dynamics via ultrafast magnon generation in technically relevant materials with strong magnetic anisotropy.
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Affiliation(s)
- B Frietsch
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - A Donges
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - R Carley
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - M Teichmann
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - J Bowlan
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - K Döbrich
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - K Carva
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-75120 Uppsala, Sweden
- Charles University, Faculty of Mathematics and Physics, DCMP, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic
| | - D Legut
- IT4Innovations-Czech National Supercomputing Centre, VSB-Technical University Ostrava, 17. listopadu 2172/15, CZ-708 00 Ostrava, Czech Republic
| | - P M Oppeneer
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-75120 Uppsala, Sweden
| | - U Nowak
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - M Weinelt
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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9
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Shim JH, Syed AA, Kim JI, Piao HG, Lee SH, Park SY, Choi YS, Lee KM, Kim HJ, Jeong JR, Hong JI, Kim DE, Kim DH. Role of non-thermal electrons in ultrafast spin dynamics of ferromagnetic multilayer. Sci Rep 2020; 10:6355. [PMID: 32286462 PMCID: PMC7156415 DOI: 10.1038/s41598-020-63452-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/27/2020] [Indexed: 11/09/2022] Open
Abstract
Understanding of ultrafast spin dynamics is crucial for future spintronic applications. In particular, the role of non-thermal electrons needs further investigation in order to gain a fundamental understanding of photoinduced demagnetization and remagnetization on a femtosecond time scale. We experimentally demonstrate that non-thermal electrons existing in the very early phase of the photoinduced demagnetization process play a key role in governing the overall ultrafast spin dynamics behavior. We simultaneously measured the time-resolved reflectivity (TR-R) and the magneto-optical Kerr effect (TR-MOKE) for a Co/Pt multilayer film. By using an extended three-temperature model (E3TM), the quantitative analysis, including non-thermal electron energy transfer into the subsystem (thermal electron, lattice, and spin), reveals that energy flow from non-thermal electrons plays a decisive role in determining the type I and II photoinduced spin dynamics behavior. Our finding proposes a new mechanism for understanding ultrafast remagnetization dynamics.
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Affiliation(s)
- Je-Ho Shim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Akbar Ali Syed
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Jea-Il Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Hong-Guang Piao
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.,College of Science, China Three Gorges University, Yichang, 443002, P. R. China
| | - Sang-Hyuk Lee
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.,Division of Industrial Metrology, Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea
| | - Seung-Young Park
- Spin Engineering Physics Team, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Yeon Suk Choi
- Spin Engineering Physics Team, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Kyung Min Lee
- Department of Material Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, South Korea
| | - Hyun-Joong Kim
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Jong-Ryul Jeong
- Department of Material Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, South Korea
| | - Jung-Il Hong
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Dong Eon Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea. .,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea.
| | - Dong-Hyun Kim
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.
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10
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Djiokap JMN, Meremianin AV, Manakov NL, Madsen LB, Hu SX, Starace AF. Molecular Symmetry-Mixed Dichroism in Double Photoionization of H_{2}. PHYSICAL REVIEW LETTERS 2019; 123:143202. [PMID: 31702195 DOI: 10.1103/physrevlett.123.143202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/24/2019] [Indexed: 06/10/2023]
Abstract
Dichroism in double photoionization of H_{2} molecules by elliptically polarized extreme ultraviolet pulses is formulated analytically as a sum of atomiclike dichroism (AD) and molecular symmetry-mixed dichroism (MSMD) terms. The MSMD originates from an interplay of ^{1}Σ_{u}^{+} and ^{1}Π_{u}^{+} continuum molecular ionization amplitudes. For detection geometries in which the AD vanishes, numerical results for the sixfold differential probabilities for opposite pulse helicities show that the MSMD is significant in the electron momentum and angular distributions and is controllable by the ellipticity.
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Affiliation(s)
- J M Ngoko Djiokap
- Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
| | - A V Meremianin
- Department of Physics, Voronezh State University, Voronezh 394006, Russia
| | - N L Manakov
- Department of Physics, Voronezh State University, Voronezh 394006, Russia
| | - L B Madsen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - S X Hu
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - Anthony F Starace
- Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
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11
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Chen J, Bovensiepen U, Eschenlohr A, Müller T, Elliott P, Gross EKU, Dewhurst JK, Sharma S. Competing Spin Transfer and Dissipation at Co/Cu(001) Interfaces on Femtosecond Timescales. PHYSICAL REVIEW LETTERS 2019; 122:067202. [PMID: 30822073 DOI: 10.1103/physrevlett.122.067202] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/28/2018] [Indexed: 05/23/2023]
Abstract
By combining interface-sensitive nonlinear magneto-optical experiments with femtosecond time resolution and ab initio time-dependent density functional theory, we show that optically excited spin dynamics at Co/Cu(001) interfaces proceeds via spin-dependent charge transfer and back transfer between Co and Cu. This ultrafast spin transfer competes with dissipation of spin angular momentum mediated by spin-orbit coupling already on sub 100 fs timescales. We thereby identify the fundamental microscopic processes during laser-induced spin transfer at a model interface for technologically relevant ferromagnetic heterostructures.
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Affiliation(s)
- J Chen
- Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
| | - U Bovensiepen
- Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
| | - A Eschenlohr
- Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
| | - T Müller
- Theory Department, Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - P Elliott
- Theory Department, Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - E K U Gross
- Theory Department, Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - J K Dewhurst
- Theory Department, Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - S Sharma
- Theory Department, Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany and Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
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12
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Abstract
All-optical switching (AOS) of magnetic materials describes the reversal of the magnetization using short (femtosecond) laser pulses, and received extensive attention in the past decade due to its high potential for fast and energy-efficient data writing in future spintronic memory applications. Unfortunately, the AOS mechanism in the ferromagnetic multilayers commonly used in spintronics needs multiple pulses for the magnetization reversal, losing its speed and energy efficiency. Here, we experimentally demonstrate on-the-fly single-pulse AOS in combination with spin Hall effect (SHE) driven motion of magnetic domains in Pt/Co/Gd synthetic-ferrimagnetic racetracks. Moreover, using field-driven-SHE-assisted domain wall (DW) motion measurements, both the SHE efficiency in the racetrack is determined and the chirality of the optically written DW’s is verified. Our experiments demonstrate that Pt/Co/Gd racetracks facilitate both single-pulse AOS as well as efficient SHE-induced domain wall motion, which might ultimately pave the way towards integrated photonic memory devices. The high speed switching and energy efficiency nature grant all-optical switching (AOS) great potential for future photonic integrated spintronic devices. Here the authors demonstrate the combination of AOS and domain wall propagation in Pt/Co/Gd synthetic ferrimagnetic racetrack for applications in photonic memory technologies.
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13
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Malvestuto M, Ciprian R, Caretta A, Casarin B, Parmigiani F. Ultrafast magnetodynamics with free-electron lasers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:053002. [PMID: 29315080 DOI: 10.1088/1361-648x/aaa211] [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
The study of ultrafast magnetodynamics has entered a new era thanks to the groundbreaking technological advances in free-electron laser (FEL) light sources. The advent of these light sources has made possible unprecedented experimental schemes for time-resolved x-ray magneto-optic spectroscopies, which are now paving the road for exploring the ultimate limits of out-of-equilibrium magnetic phenomena. In particular, these studies will provide insights into elementary mechanisms governing spin and orbital dynamics, therefore contributing to the development of ultrafast devices for relevant magnetic technologies. This topical review focuses on recent advancement in the study of non-equilibrium magnetic phenomena from the perspective of time-resolved extreme ultra violet (EUV) and soft x-ray spectroscopies at FELs with highlights of some important experimental results.
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Affiliation(s)
- Marco Malvestuto
- Elettra-Sincrotrone Trieste S.C.p.A. Strada Statale 14-km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
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14
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Zhang GP, Jenkins T, Bennett M, Bai YH. Manifestation of intra-atomic 5d6s-4f exchange coupling in photoexcited gadolinium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:495807. [PMID: 29105644 DOI: 10.1088/1361-648x/aa986c] [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
Intra-atomic exchange couplings (IECs) between 5d6s and 4f electrons are ubiquitous in rare-earth metals and play a critical role in spin dynamics. However, detecting them in real time domain has been difficult. Here we show the direct evidence of IEC between 5d6s and 4f electrons in gadolinium. Upon femtosecond laser excitation, 5d6s electrons are directly excited; their majority bands shift toward the Fermi level while their minority bands do the opposite. For the first time, our first-principles minority shift now agrees with the experiment quantitatively. Excited 5d6s electrons lower the exchange potential barrier for 4f electrons, so the 4f states are also shifted in energy, a prediction that can be tested experimentally. Although a significant number of 5d6s electrons, some several eV below the Fermi level, are excited out of the Fermi sea, there is no change in the 4f states, a clear manifestation of intra-atomic exchange coupling.
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Affiliation(s)
- G P Zhang
- Department of Physics, Indiana State University, Terre Haute, IN 47809, United States of America
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15
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Thielemann-Kühn N, Schick D, Pontius N, Trabant C, Mitzner R, Holldack K, Zabel H, Föhlisch A, Schüßler-Langeheine C. Ultrafast and Energy-Efficient Quenching of Spin Order: Antiferromagnetism Beats Ferromagnetism. PHYSICAL REVIEW LETTERS 2017; 119:197202. [PMID: 29219516 DOI: 10.1103/physrevlett.119.197202] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Indexed: 06/07/2023]
Abstract
By comparing femtosecond laser pulse induced ferro- and antiferromagnetic dynamics in one and the same material-metallic dysprosium-we show both to behave fundamentally different. Antiferromagnetic order is considerably faster and much more efficiently reduced by optical excitation than its ferromagnetic counterpart. We assign the fast and extremely efficient process in the antiferromagnet to an interatomic transfer of angular momentum within the spin system. Our findings imply that this angular momentum transfer channel is effective in other magnetic metals with nonparallel spin alignment. They also point out a possible route towards energy-efficient spin manipulation for magnetic devices.
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Affiliation(s)
- Nele Thielemann-Kühn
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam, Germany
| | - Daniel Schick
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Niko Pontius
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Christoph Trabant
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam, Germany
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany
| | - Rolf Mitzner
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Karsten Holldack
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Hartmut Zabel
- Institut für Physik, Johannes-Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Alexander Föhlisch
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam, Germany
| | - Christian Schüßler-Langeheine
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
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16
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Koc A, Reinhardt M, von Reppert A, Rössle M, Leitenberger W, Gleich M, Weinelt M, Zamponi F, Bargheer M. Grueneisen-approach for the experimental determination of transient spin and phonon energies from ultrafast x-ray diffraction data: gadolinium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:264001. [PMID: 28557803 DOI: 10.1088/1361-648x/aa7187] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We study gadolinium thin films as a model system for ferromagnets with negative thermal expansion. Ultrashort laser pulses heat up the electronic subsystem and we follow the transient strain via ultrafast x-ray diffraction. In terms of a simple Grueneisen approach, the strain is decomposed into two contributions proportional to the thermal energy of spin and phonon subsystems. Our analysis reveals that upon femtosecond laser excitation, phonons and spins can be driven out of thermal equilibrium for several nanoseconds.
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Affiliation(s)
- A Koc
- Helmholtz Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany
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17
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Silly MG, Ferté T, Tordeux MA, Pierucci D, Beaulieu N, Chauvet C, Pressacco F, Sirotti F, Popescu H, Lopez-Flores V, Tortarolo M, Sacchi M, Jaouen N, Hollander P, Ricaud JP, Bergeard N, Boeglin C, Tudu B, Delaunay R, Luning J, Malinowski G, Hehn M, Baumier C, Fortuna F, Krizmancic D, Stebel L, Sergo R, Cautero G. Pump-probe experiments at the TEMPO beamline using the low-α operation mode of Synchrotron SOLEIL. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:886-897. [PMID: 28664896 DOI: 10.1107/s1600577517007913] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated to pump-probe experiments. Among others, the low-α mode operation is characterized by shorter pulse duration and represents the natural bridge between 50 ps synchrotron pulses and femtosecond experiments. Here, the capabilities in low-α mode of the experimental set-ups developed at the TEMPO beamline to perform pump-probe experiments with soft X-rays based on photoelectron or photon detection are presented. A 282 kHz repetition-rate femtosecond laser is synchronized with the synchrotron radiation time structure to induce fast electronic and/or magnetic excitations. Detection is performed using a two-dimensional space resolution plus time resolution detector based on microchannel plates equipped with a delay line. Results of time-resolved photoelectron spectroscopy, circular dichroism and magnetic scattering experiments are reported, and their respective advantages and limitations in the framework of high-time-resolution pump-probe experiments compared and discussed.
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Affiliation(s)
- Mathieu G Silly
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Tom Ferté
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | - Marie Agnes Tordeux
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Debora Pierucci
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Nathan Beaulieu
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Christian Chauvet
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Federico Pressacco
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Fausto Sirotti
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Horia Popescu
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Victor Lopez-Flores
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Marina Tortarolo
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Maurizio Sacchi
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Philippe Hollander
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Jean Paul Ricaud
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Nicolas Bergeard
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | - Christine Boeglin
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | - Bharati Tudu
- Sorbonne Universités, UPMC Université Paris VI, CNRS, Laboratoire de Chimie Physique - Matière et Rayonnement, Paris 75005, France
| | - Renaud Delaunay
- Sorbonne Universités, UPMC Université Paris VI, CNRS, Laboratoire de Chimie Physique - Matière et Rayonnement, Paris 75005, France
| | - Jan Luning
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, Gif sur Yvette 91192, France
| | - Gregory Malinowski
- P2M - Institut Jean Lamour UMR7198, CNRS - Université de Lorraine, Vandoeuvre-les-Nancy 54506, France
| | - Michel Hehn
- P2M - Institut Jean Lamour UMR7198, CNRS - Université de Lorraine, Vandoeuvre-les-Nancy 54506, France
| | - Cédric Baumier
- CSNSM, Université Paris Sud and CNRS/IN2P3, Batiment 104 et 108, Orsay 91405, France
| | - Franck Fortuna
- CSNSM, Université Paris Sud and CNRS/IN2P3, Batiment 104 et 108, Orsay 91405, France
| | - Damjan Krizmancic
- Laboratorio TASC, IOM-CNR, SS 14 Km 163.5, Basovizza, I-34149 Trieste, Italy
| | - Luigi Stebel
- ELETTRA Sincrotrone Trieste SCpA, Area Science Park, Strada Statale 14 Km 163.5, I-34012 Basovizza, Italy
| | - Rudi Sergo
- ELETTRA Sincrotrone Trieste SCpA, Area Science Park, Strada Statale 14 Km 163.5, I-34012 Basovizza, Italy
| | - Giuseppe Cautero
- ELETTRA Sincrotrone Trieste SCpA, Area Science Park, Strada Statale 14 Km 163.5, I-34012 Basovizza, Italy
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18
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Bobowski K, Gleich M, Pontius N, Schüßler-Langeheine C, Trabant C, Wietstruk M, Frietsch B, Weinelt M. Influence of the pump pulse wavelength on the ultrafast demagnetization of Gd(0 0 0 1) thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:234003. [PMID: 28398211 DOI: 10.1088/1361-648x/aa6c92] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We studied the magnetization dynamics of gadolinium metal after femtosecond laser excitation recording the x-ray magnetic circular dichroism in reflection (XMCD-R) at the Gd M 5 absorption edge. Varying the photon energy of the pump pulse allows us to change the initial energy distribution of photoexcited carriers. The overall similar response for excitation with 0.95, 1.55 and 3.10 eV photons at comparable pump fluences indicates that ultrafast ballistic carrier transport leads to a homogeneous energy distribution on the femtosecond timescale in the probed sample volume. Differences are observed in the initial ultrafast demagnetization magnitude. They are attributed to an enhanced spin-flip probability at higher electron energies characterizing the non-thermal electron distribution.
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Affiliation(s)
- Kamil Bobowski
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
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19
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Fognini A, Michlmayr TU, Vaterlaus A, Acremann Y. Laser-induced ultrafast spin current pulses: a thermodynamic approach. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:214002. [PMID: 28441145 DOI: 10.1088/1361-648x/aa6a76] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ultrafast demagnetization process allows for the generation of femtosecond spin current pulses. Here, we present a thermodynamic model of the spin current generation process, based on the chemical potential gradients as the driving force for the spin current. We demonstrate that the laser-induced spin current can be estimated by an easy to understand diffusion model.
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Affiliation(s)
- A Fognini
- Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft 2628 CJ, The Netherlands
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20
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Razdolski I, Alekhin A, Martens U, Bürstel D, Diesing D, Münzenberg M, Bovensiepen U, Melnikov A. Analysis of the time-resolved magneto-optical Kerr effect for ultrafast magnetization dynamics in ferromagnetic thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:174002. [PMID: 28349899 DOI: 10.1088/1361-648x/aa63c6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We discuss fundamental aspects of laser-induced ultrafast demagnetization probed by the time-resolved magneto-optical Kerr effect (MOKE). Studying thin Fe films on MgO substrate in the absence of electronic transport, we demonstrate how to disentangle pump-induced variations of magnetization and magneto-optical coefficients. We provide a mathematical formalism for retrieving genuine laser-induced magnetization dynamics and discuss its applicability in real experimental situations. We further stress the importance of temporal resolution achieved in the experiments and argue that measurements of both time-resolved MOKE rotation and ellipticity are needed for the correct assessment of magnetization dynamics on sub-picosecond timescales. The framework developed here sheds light onto the details of the time-resolved MOKE technique and contributes to the understanding of the interplay between ultrafast laser-induced optical and magnetic effects.
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Affiliation(s)
- I Razdolski
- Fritz Haber Institute of Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
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21
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Hellman F, Hoffmann A, Tserkovnyak Y, Beach GSD, Fullerton EE, Leighton C, MacDonald AH, Ralph DC, Arena DA, Dürr HA, Fischer P, Grollier J, Heremans JP, Jungwirth T, Kimel AV, Koopmans B, Krivorotov IN, May SJ, Petford-Long AK, Rondinelli JM, Samarth N, Schuller IK, Slavin AN, Stiles MD, Tchernyshyov O, Thiaville A, Zink BL. Interface-Induced Phenomena in Magnetism. REVIEWS OF MODERN PHYSICS 2017; 89:025006. [PMID: 28890576 PMCID: PMC5587142 DOI: 10.1103/revmodphys.89.025006] [Citation(s) in RCA: 192] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This article reviews static and dynamic interfacial effects in magnetism, focusing on interfacially-driven magnetic effects and phenomena associated with spin-orbit coupling and intrinsic symmetry breaking at interfaces. It provides a historical background and literature survey, but focuses on recent progress, identifying the most exciting new scientific results and pointing to promising future research directions. It starts with an introduction and overview of how basic magnetic properties are affected by interfaces, then turns to a discussion of charge and spin transport through and near interfaces and how these can be used to control the properties of the magnetic layer. Important concepts include spin accumulation, spin currents, spin transfer torque, and spin pumping. An overview is provided to the current state of knowledge and existing review literature on interfacial effects such as exchange bias, exchange spring magnets, spin Hall effect, oxide heterostructures, and topological insulators. The article highlights recent discoveries of interface-induced magnetism and non-collinear spin textures, non-linear dynamics including spin torque transfer and magnetization reversal induced by interfaces, and interfacial effects in ultrafast magnetization processes.
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Affiliation(s)
- Frances Hellman
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Axel Hoffmann
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Eric E Fullerton
- Center for Memory and Recording Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0401, USA
| | - Chris Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Allan H MacDonald
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-0264, USA
| | - Daniel C Ralph
- Physics Department, Cornell University, Ithaca, New York 14853, USA; Kavli Institute at Cornell, Cornell University, Ithaca, New York 14853, USA
| | - Dario A Arena
- Department of Physics, University of South Florida, Tampa, Florida 33620-7100, USA
| | - Hermann A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Physics Department, University of California, 1156 High Street, Santa Cruz, California 94056, USA
| | - Julie Grollier
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - Joseph P Heremans
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA; Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA; Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Tomas Jungwirth
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Praha 6, Czech Republic; School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Alexey V Kimel
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
| | - Bert Koopmans
- Department of Applied Physics, Center for NanoMaterials, COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ilya N Krivorotov
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Steven J May
- Department of Materials Science & Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Amanda K Petford-Long
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA
| | - James M Rondinelli
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Nitin Samarth
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ivan K Schuller
- Department of Physics and Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA; Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Andrei N Slavin
- Department of Physics, Oakland University, Rochester, Michigan 48309, USA
| | - Mark D Stiles
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6202, USA
| | - Oleg Tchernyshyov
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - André Thiaville
- Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France
| | - Barry L Zink
- Department of Physics and Astronomy, University of Denver, Denver, CO 80208, USA
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22
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Element Selective Probe of the Ultra-Fast Magnetic Response to an Element Selective Excitation in Fe-Ni Compounds Using a Two-Color FEL Source. PHOTONICS 2017. [DOI: 10.3390/photonics4010006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Carva K, Baláž P, Radu I. Laser-Induced Ultrafast Magnetic Phenomena. HANDBOOK OF MAGNETIC MATERIALS 2017. [DOI: 10.1016/bs.hmm.2017.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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24
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Jang H, Kang BY, Cho BK, Hashimoto M, Lu D, Burns CA, Kao CC, Lee JS. Observation of Orbital Order in the Half-Filled 4f Gd Compound. PHYSICAL REVIEW LETTERS 2016; 117:216404. [PMID: 27911536 DOI: 10.1103/physrevlett.117.216404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Indexed: 06/06/2023]
Abstract
Half-filled electron systems, even with the maximized spin angular moment, have been given little attention because of their zero-orbital angular moment according to Hund's rule. Nevertheless, there are several measurements that show evidence of a nonzero orbital moment as well as spin-orbit coupling. Here we report for the first time the orbital order in a half-filled 4f-electron system GdB_{4}, using the resonant soft x-ray scattering at Gd M_{4,5}-edges. Furthermore, we discovered that the development of this orbital order is strongly coupled with the antiferromagnetic spin order. These results clearly demonstrate that even in half-filled electron systems the orbital angular moment can be an important parameter to describe material properties, and may provide significant opportunities for tailoring new correlated electron systems.
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Affiliation(s)
- H Jang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - B Y Kang
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C A Burns
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008, USA
| | - C-C Kao
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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25
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von Reppert A, Pudell J, Koc A, Reinhardt M, Leitenberger W, Dumesnil K, Zamponi F, Bargheer M. Persistent nonequilibrium dynamics of the thermal energies in the spin and phonon systems of an antiferromagnet. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2016; 3:054302. [PMID: 27679803 PMCID: PMC5018005 DOI: 10.1063/1.4961253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/04/2016] [Indexed: 05/22/2023]
Abstract
We present a temperature and fluence dependent Ultrafast X-Ray Diffraction study of a laser-heated antiferromagnetic dysprosium thin film. The loss of antiferromagnetic order is evidenced by a pronounced lattice contraction. We devise a method to determine the energy flow between the phonon and spin system from calibrated Bragg peak positions in thermal equilibrium. Reestablishing the magnetic order is much slower than the cooling of the lattice, especially around the Néel temperature. Despite the pronounced magnetostriction, the transfer of energy from the spin system to the phonons in Dy is slow after the spin-order is lost.
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Affiliation(s)
- A von Reppert
- Institut für Physik and Astronomie, Universität Potsdam , Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - J Pudell
- Institut für Physik and Astronomie, Universität Potsdam , Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - A Koc
- Helmholtz Zentrum Berlin , Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - M Reinhardt
- Helmholtz Zentrum Berlin , Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - W Leitenberger
- Institut für Physik and Astronomie, Universität Potsdam , Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - K Dumesnil
- Institut Jean Lamour (UMR CNRS 7198), Université Lorraine , Boulevard des Aiguillettes B.P. 239, F-54500 Vandoeuvre les Nancy Cédex, France
| | - F Zamponi
- Institut für Physik and Astronomie, Universität Potsdam , Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
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26
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Rettig L, Dornes C, Thielemann-Kühn N, Pontius N, Zabel H, Schlagel DL, Lograsso TA, Chollet M, Robert A, Sikorski M, Song S, Glownia JM, Schüßler-Langeheine C, Johnson SL, Staub U. Itinerant and Localized Magnetization Dynamics in Antiferromagnetic Ho. PHYSICAL REVIEW LETTERS 2016; 116:257202. [PMID: 27391747 DOI: 10.1103/physrevlett.116.257202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Indexed: 05/19/2023]
Abstract
Using femtosecond time-resolved resonant magnetic x-ray diffraction at the Ho L_{3} absorption edge, we investigate the demagnetization dynamics in antiferromagnetically ordered metallic Ho after femtosecond optical excitation. Tuning the x-ray energy to the electric dipole (E1, 2p→5d) or quadrupole (E2, 2p→4f) transition allows us to selectively and independently study the spin dynamics of the itinerant 5d and localized 4f electronic subsystems via the suppression of the magnetic (2 1 3-τ) satellite peak. We find demagnetization time scales very similar to ferromagnetic 4f systems, suggesting that the loss of magnetic order occurs via a similar spin-flip process in both cases. The simultaneous demagnetization of both subsystems demonstrates strong intra-atomic 4f-5d exchange coupling. In addition, an ultrafast lattice contraction due to the release of magneto-striction leads to a transient shift of the magnetic satellite peak.
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Affiliation(s)
- L Rettig
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Current Address: Abteilung Physikalische Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany
| | - C Dornes
- Institute for Quantum Electronics, Physics Department, ETH Zürich, 8093 Zürich, Switzerland
| | - N Thielemann-Kühn
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam-Golm, Germany
| | - N Pontius
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - H Zabel
- Institute for Experimental Physics, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - D L Schlagel
- Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011, USA
| | - T A Lograsso
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - M Chollet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - A Robert
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M Sikorski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - S Song
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - J M Glownia
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - C Schüßler-Langeheine
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zürich, 8093 Zürich, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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27
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Zhang GP, Bai YH, George TF. Ultrafast reduction of exchange splitting in ferromagnetic nickel. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:236004. [PMID: 27160931 DOI: 10.1088/0953-8984/28/23/236004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A decade ago Rhie et al (2003 Phys. Rev. Lett. 90 247201) reported that when ferromagnetic nickel is subject to an intense ultrashort laser pulse, its exchange splitting is reduced quickly. But to simulate such reduction remains a big challenge. The popular rigid band approximation (RBA), where both the band structure and the exchange splitting are held fixed before and after laser excitation, is unsuitable for this purpose, while the time-dependent density functional theory could be time-consuming. To overcome these difficulties, we propose a time-dependent Liouville and density functional theory (TDLDFT) that integrates the time-dependent Liouville equation into the density functional theory. As a result, the excited charge density is reiterated back into the Kohn-Sham equation, and the band structure is allowed to change dynamically. Even with the ground-state density functional, a larger demagnetization than RBA is found; after we expand Ortenzi's spin scaling method into an excited-state (laser) density functional, we find that the exchange splitting is indeed strongly reduced, as seen in the experiment. Both the majority and minority bands are shifted toward the Fermi level, but the majority shifts a lot more. The ultrafast reduction in exchange splitting occurs concomitantly with demagnetization. While our current theory is still unable to yield the same percentage loss in the spin moment as observed in the experiment, it predicts a correct trend that agrees with the experiments. With a better functional, we believe that our results can be further improved.
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Affiliation(s)
- G P Zhang
- Department of Physics, Indiana State University, Terre Haute, IN 47809, USA
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28
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Liu Q, Zhu XD, Wang LH, Cheong SW, Tobey RI. Ultrafast magnetization and structural dynamics in the intercalated transition metal dichalcogenides Fe0.25TaS2 and Mn0.25TaS2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:194002. [PMID: 27094012 DOI: 10.1088/0953-8984/28/19/194002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We measure magnetization and structural dynamics in two intercalant-ordered transition metal dichalcogenides: Fe0.25TaS2 and Mn0.25TaS2. The structurally equivalent materials allow us to probe the effect of orbital angular momentum which is active in Fe0.25TaS2 and absent in Mn0.25TaS2. Interestingly, we find that the magnetooptics dynamics are nearly indistinguishable in these two materials, in contradiction to conventional explanations of a spin-lattice mechanism. We compare our results to other materials where spin-lattice demagnetization has been put forth as a demagnetization channel.
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Affiliation(s)
- Q Liu
- Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747AG, The Netherlands
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29
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Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering. Nat Commun 2016; 7:10343. [PMID: 26757813 PMCID: PMC4735510 DOI: 10.1038/ncomms10343] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/03/2015] [Indexed: 11/28/2022] Open
Abstract
The advent of free-electron laser (FEL) sources delivering two synchronized pulses of different wavelengths (or colours) has made available a whole range of novel pump–probe experiments. This communication describes a major step forward using a new configuration of the FERMI FEL-seeded source to deliver two pulses with different wavelengths, each tunable independently over a broad spectral range with adjustable time delay. The FEL scheme makes use of two seed laser beams of different wavelengths and of a split radiator section to generate two extreme ultraviolet pulses from distinct portions of the same electron bunch. The tunability range of this new two-colour source meets the requirements of double-resonant FEL pump/FEL probe time-resolved studies. We demonstrate its performance in a proof-of-principle magnetic scattering experiment in Fe–Ni compounds, by tuning the FEL wavelengths to the Fe and Ni 3p resonances. Two-colour X-ray free electron laser is a powerful tool for pump–probe measurements, but currently constrained by limited tunability. Here, Ferrari et al. develop a configuration that allows tuning both the pump and the probe to specific electronic excitations, providing element selectivity.
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30
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Stepanov AG, Hauri CP. Short X-ray pulses from third-generation light sources. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:141-151. [PMID: 26698056 DOI: 10.1107/s1600577515019281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
High-brightness X-ray radiation produced by third-generation synchrotron light sources (TGLS) has been used for numerous time-resolved investigations in many different scientific fields. The typical time duration of X-ray pulses delivered by these large-scale machines is about 50-100 ps. A growing number of time-resolved studies would benefit from X-ray pulses with two or three orders of magnitude shorter duration. Here, techniques explored in the past for shorter X-ray pulse emission at TGLS are reviewed and the perspective towards the realisation of picosecond and sub-picosecond X-ray pulses are discussed.
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Affiliation(s)
- A G Stepanov
- Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - C P Hauri
- Paul Scherrer Institute, 5232 Villigen, Switzerland
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31
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Svetina C, Mahne N, Raimondi L, Caretta A, Casarin B, Dell'Angela M, Malvestuto M, Parmigiani F, Zangrando M. MagneDyn: the beamline for magneto dynamics studies at FERMI. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:98-105. [PMID: 26698050 DOI: 10.1107/s1600577515022080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/18/2015] [Indexed: 06/05/2023]
Abstract
The future Magneto Dynamics (MagneDyn) beamline will be devoted to study the electronic states and the local magnetic properties of excited and transient states of complex systems by means of the time-resolved X-ray absorption spectroscopy technique. The beamline will use FERMI's high-energy source covering the wavelength range from 60 nm down to 1.3 nm. An on-line photon energy spectrometer will allow spectra to be measured with high resolution while delivering most of the beam to the end-stations. Downstream the beam will be possibly split and delayed, by means of a delay line, and then focused with a set of active Kirkpatrick-Baez mirrors. These mirrors will be able to focus the radiation in one of the two MagneDyn experimental chambers: the electromagnet end-station and the resonant inelastic X-ray scattering end-station. After an introduction of the MagneDyn scientific case, the layout will be discussed showing the expected performances of the beamline.
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Affiliation(s)
- Cristian Svetina
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Nicola Mahne
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Lorenzo Raimondi
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Antonio Caretta
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Barbara Casarin
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Martina Dell'Angela
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Marco Malvestuto
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Fulvio Parmigiani
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Marco Zangrando
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
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32
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Andres B, Christ M, Gahl C, Wietstruk M, Weinelt M, Kirschner J. Separating Exchange Splitting from Spin Mixing in Gadolinium by Femtosecond Laser Excitation. PHYSICAL REVIEW LETTERS 2015; 115:207404. [PMID: 26613472 DOI: 10.1103/physrevlett.115.207404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 06/05/2023]
Abstract
Employing spin-, time-, and energy-resolved photoemission spectroscopy, we present the first study on the spin polarization of a single electronic state after ultrafast optical excitation. Our investigation concentrates on the majority-spin component of the d-band-derived Gd(0001) surface state d(z(2))(↑). While its binding energy shows a rapid Stoner-like shift by 90 meV with an exponential time constant of τ(E)=0.6±0.1 ps, the d(z(2))(↑) spin polarization remains nearly constant within the first picoseconds and decays with τ(S)=15±8 ps. This behavior is in clear contrast to the equilibrium phase transition, where the spin polarization vanishes at the Curie temperature.
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Affiliation(s)
- Beatrice Andres
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Marc Christ
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Cornelius Gahl
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Marko Wietstruk
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Martin Weinelt
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Jürgen Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle/Saale, Germany
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33
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Frietsch B, Bowlan J, Carley R, Teichmann M, Wienholdt S, Hinzke D, Nowak U, Carva K, Oppeneer PM, Weinelt M. Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal. Nat Commun 2015; 6:8262. [PMID: 26355196 PMCID: PMC4579838 DOI: 10.1038/ncomms9262] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 08/04/2015] [Indexed: 01/26/2023] Open
Abstract
The Heisenberg–Dirac intra-atomic exchange coupling is responsible for the formation of the atomic spin moment and thus the strongest interaction in magnetism. Therefore, it is generally assumed that intra-atomic exchange leads to a quasi-instantaneous aligning process in the magnetic moment dynamics of spins in separate, on-site atomic orbitals. Following ultrashort optical excitation of gadolinium metal, we concurrently record in photoemission the 4f magnetic linear dichroism and 5d exchange splitting. Their dynamics differ by one order of magnitude, with decay constants of 14 versus 0.8 ps, respectively. Spin dynamics simulations based on an orbital-resolved Heisenberg Hamiltonian combined with first-principles calculations explain the particular dynamics of 5d and 4f spin moments well, and corroborate that the 5d exchange splitting traces closely the 5d spin-moment dynamics. Thus gadolinium shows disparate dynamics of the localized 4f and the itinerant 5d spin moments, demonstrating a breakdown of their intra-atomic exchange alignment on a picosecond timescale. Due the strength of the intra-atomic exchange interaction, it is generally assumed that alignment of spin moments in intra-atomic orbitals is quasi-instantaneous. Here, the authors demonstrate the breakdown of this relation between the 4f and 5d electrons in gadolinium following ultrashort optical excitation.
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Affiliation(s)
- B Frietsch
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.,Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany
| | - J Bowlan
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.,Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany
| | - R Carley
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.,Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany
| | - M Teichmann
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.,Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany
| | - S Wienholdt
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - D Hinzke
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - U Nowak
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - K Carva
- Department of Physics and Astronomy, Uppsala University, PO Box 516, 75120 Uppsala, Sweden.,Charles University, Faculty of Mathematics and Physics, DCMP, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, PO Box 516, 75120 Uppsala, Sweden
| | - M Weinelt
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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34
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Oroszlány L, Deák A, Simon E, Khmelevskyi S, Szunyogh L. Magnetism of Gadolinium: A First-Principles Perspective. PHYSICAL REVIEW LETTERS 2015; 115:096402. [PMID: 26371666 DOI: 10.1103/physrevlett.115.096402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Indexed: 06/05/2023]
Abstract
By calculating the spectral density of states in the ferromagnetic ground state and in the high temperature paramagnetic phase we provide the first concise study of finite temperature effects on the electronic structure of the bulk and the surface of gadolinium metal. The variation of calculated spectral properties of the Fermi surface and the density of states in the bulk and at the surface are in good agreement with recent photoemission experiments performed in both ferromagnetic and paramagnetic phases. In the paramagnetic state we find vanishing spin splitting of the conduction band, but finite local spin moments both in bulk and at the surface. We clearly demonstrate that the formation of these local spin moments in the conduction band is due to the asymmetry of the density of states in the two spin channels, suggesting a complex, non-Stoner behavior. We, therefore, suggest that the vanishing or nearly vanishing spin splitting of spectral features cannot be used as an indicator for Stoner-like magnetism.
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Affiliation(s)
- L Oroszlány
- Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
- Department of Physics of Complex Systems, Eötvös University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - A Deák
- Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
| | - E Simon
- Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
| | - S Khmelevskyi
- Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
- Faculty of Physics, Computational Materials Physics, University of Vienna, Vienna A-1090, Austria
| | - L Szunyogh
- Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
- MTA-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
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35
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Ultrafast optical tuning of ferromagnetism via the carrier density. Nat Commun 2015; 6:6724. [DOI: 10.1038/ncomms7724] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 02/23/2015] [Indexed: 11/08/2022] Open
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36
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van der Laan G, Figueroa AI. X-ray magnetic circular dichroism—A versatile tool to study magnetism. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.03.018] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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37
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Holldack K, Bahrdt J, Balzer A, Bovensiepen U, Brzhezinskaya M, Erko A, Eschenlohr A, Follath R, Firsov A, Frentrup W, Le Guyader L, Kachel T, Kuske P, Mitzner R, Müller R, Pontius N, Quast T, Radu I, Schmidt JS, Schüssler-Langeheine C, Sperling M, Stamm C, Trabant C, Föhlisch A. FemtoSpeX: a versatile optical pump-soft X-ray probe facility with 100 fs X-ray pulses of variable polarization. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:1090-1104. [PMID: 25177998 DOI: 10.1107/s1600577514012247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 05/27/2014] [Indexed: 06/03/2023]
Abstract
Here the major upgrades of the femtoslicing facility at BESSY II (Khan et al., 2006) are reviewed, giving a tutorial on how elliptical-polarized ultrashort soft X-ray pulses from electron storage rings are generated at high repetition rates. Employing a 6 kHz femtosecond-laser system consisting of two amplifiers that are seeded by one Ti:Sa oscillator, the total average flux of photons of 100 fs duration (FWHM) has been increased by a factor of 120 to up to 10(6) photons s(-1) (0.1% bandwidth)(-1) on the sample in the range from 250 to 1400 eV. Thanks to a new beamline design, a factor of 20 enhanced flux and improvements of the stability together with the top-up mode of the accelerator have been achieved. The previously unavoidable problem of increased picosecond-background at higher repetition rates, caused by `halo' photons, has also been solved by hopping between different `camshaft' bunches in a dedicated fill pattern (`3+1 camshaft fill') of the storage ring. In addition to an increased X-ray performance at variable (linear and elliptical) polarization, the sample excitation in pump-probe experiments has been considerably extended using an optical parametric amplifier that supports the range from the near-UV to the far-IR regime. Dedicated endstations covering ultrafast magnetism experiments based on time-resolved X-ray circular dichroism have been either upgraded or, in the case of time-resolved resonant soft X-ray diffraction and reflection, newly constructed and adapted to femtoslicing requirements. Experiments at low temperatures down to 6 K and magnetic fields up to 0.5 T are supported. The FemtoSpeX facility is now operated as a 24 h user facility enabling a new class of experiments in ultrafast magnetism and in the field of transient phenomena and phase transitions in solids.
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Affiliation(s)
- Karsten Holldack
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Johannes Bahrdt
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Andreas Balzer
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Uwe Bovensiepen
- Fakultät für Physik, Universität Duisburg-Essen, Lotharstrasse 1, Duisburg 47048, Germany
| | - Maria Brzhezinskaya
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Alexei Erko
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Andrea Eschenlohr
- Fakultät für Physik, Universität Duisburg-Essen, Lotharstrasse 1, Duisburg 47048, Germany
| | - Rolf Follath
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Alexander Firsov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Winfried Frentrup
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Loïc Le Guyader
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Torsten Kachel
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Peter Kuske
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Rolf Mitzner
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Roland Müller
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Niko Pontius
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Torsten Quast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Ilie Radu
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Jan Simon Schmidt
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | | | - Mike Sperling
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Christian Stamm
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Christoph Trabant
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - Alexander Föhlisch
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
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38
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Ultrafast angular momentum transfer in multisublattice ferrimagnets. Nat Commun 2014; 5:3466. [DOI: 10.1038/ncomms4466] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 02/18/2014] [Indexed: 11/09/2022] Open
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39
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Brzhezinskaya M, Firsov A, Holldack K, Kachel T, Mitzner R, Pontius N, Schmidt JS, Sperling M, Stamm C, Föhlisch A, Erko A. A novel monochromator for experiments with ultrashort X-ray pulses. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:522-530. [PMID: 23765293 DOI: 10.1107/s0909049513008613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
Aiming at advancing storage-ring-based ultrafast X-ray science, over the past few years many upgrades have been undertaken to continue improving beamline performance and photon flux at the Femtoslicing facility at BESSY II. In this article the particular design upgrade of one of the key optical components, the zone-plate monochromator (ZPM) beamline, is reported. The beamline is devoted to optical pump/soft X-ray probe applications with 100 fs (FWHM) X-ray pulses in the soft X-ray range at variable polarization. A novel approach consisting of an array of nine off-axis reflection zone plates is used for a gapless coverage of the spectral range between 410 and 1333 eV at a designed resolution of E/ΔE = 500 and a pulse elongation of only 30 fs. With the upgrade of the ZPM the following was achieved: a smaller focus, an improved spectral resolution and bandwidth as well as excellent long-term stability. The beamline will enable a new class of ultrafast applications with variable optical excitation wavelength and variable polarization.
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Affiliation(s)
- Maria Brzhezinskaya
- Institute for Nanometer Optics and Technology, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
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40
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Frietsch B, Carley R, Döbrich K, Gahl C, Teichmann M, Schwarzkopf O, Wernet P, Weinelt M. A high-order harmonic generation apparatus for time- and angle-resolved photoelectron spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:075106. [PMID: 23902105 DOI: 10.1063/1.4812992] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We present a table top setup for time- and angle-resolved photoelectron spectroscopy to investigate band structure dynamics of correlated materials driven far from equilibrium by femtosecond laser pulse excitation. With the electron-phonon equilibration time being in the order of 1-2 ps it is necessary to achieve sub-picosecond time resolution. Few techniques provide both the necessary time and energy resolution to map non-equilibrium states of the band structure. Laser-driven high-order harmonic generation is such a technique. In our experiment, a grating monochromator delivers tunable photon energies up to 40 eV. A photon energy bandwidth of 150 meV and a pulse duration of 100 fs FWHM allow us to cover the k-space necessary to map valence bands at different kz and detect outer core states.
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Affiliation(s)
- B Frietsch
- Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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41
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Hassdenteufel A, Hebler B, Schubert C, Liebig A, Teich M, Helm M, Aeschlimann M, Albrecht M, Bratschitsch R. Thermally assisted all-optical helicity dependent magnetic switching in amorphous Fe(100-x)Tb(x) alloy films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:3122-8. [PMID: 23616209 DOI: 10.1002/adma.201300176] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 03/13/2013] [Indexed: 05/23/2023]
Abstract
All-optical switching (AOS) in ferrimagnetic Fe(100-x)Tb(x) alloys is presented. AOS is witnessed below, above, and in samples without a magnetic compensation point. It is found that AOS is associated with laser heating up to the Curie temperature and intimately linked to a low remanent sample magnetization. Above a threshold magnetization of 220 emu/cc helicity dependent AOS is replaced by pure thermal demagnetization.
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42
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Jankowiak A, Wüstefeld G. Low-α Operation of BESSY II and Future Plans for an Alternating Bunch Length Scheme BESSYVSR. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/08940886.2013.791212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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43
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Graves CE, Reid AH, Wang T, Wu B, de Jong S, Vahaplar K, Radu I, Bernstein DP, Messerschmidt M, Müller L, Coffee R, Bionta M, Epp SW, Hartmann R, Kimmel N, Hauser G, Hartmann A, Holl P, Gorke H, Mentink JH, Tsukamoto A, Fognini A, Turner JJ, Schlotter WF, Rolles D, Soltau H, Strüder L, Acremann Y, Kimel AV, Kirilyuk A, Rasing T, Stöhr J, Scherz AO, Dürr HA. Nanoscale spin reversal by non-local angular momentum transfer following ultrafast laser excitation in ferrimagnetic GdFeCo. NATURE MATERIALS 2013; 12:293-8. [PMID: 23503010 DOI: 10.1038/nmat3597] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 02/07/2012] [Indexed: 05/19/2023]
Abstract
Ultrafast laser techniques have revealed extraordinary spin dynamics in magnetic materials that equilibrium descriptions of magnetism cannot explain. Particularly important for future applications is understanding non-equilibrium spin dynamics following laser excitation on the nanoscale, yet the limited spatial resolution of optical laser techniques has impeded such nanoscale studies. Here we present ultrafast diffraction experiments with an X-ray laser that probes the nanoscale spin dynamics following optical laser excitation in the ferrimagnetic alloy GdFeCo, which exhibits macroscopic all-optical switching. Our study reveals that GdFeCo displays nanoscale chemical and magnetic inhomogeneities that affect the spin dynamics. In particular, we observe Gd spin reversal in Gd-rich nanoregions within the first picosecond driven by the non-local transfer of angular momentum from larger adjacent Fe-rich nanoregions. These results suggest that a magnetic material's microstructure can be engineered to control transient laser-excited spins, potentially allowing faster (~ 1 ps) spin reversal than in present technologies.
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Affiliation(s)
- C E Graves
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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44
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Khorsand AR, Savoini M, Kirilyuk A, Kimel AV, Tsukamoto A, Itoh A, Rasing T. Element-specific probing of ultrafast spin dynamics in multisublattice magnets with visible light. PHYSICAL REVIEW LETTERS 2013; 110:107205. [PMID: 23521292 DOI: 10.1103/physrevlett.110.107205] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Indexed: 05/22/2023]
Abstract
We demonstrate the feasibility of element-specific probing of ultrafast spin dynamics in the multisublattice magnet TbFe in the visible spectral range. In particular, we show that one can selectively study the dynamics of Tb and Fe sublattices choosing the wavelength of light below and above 610 nm, respectively. We observe that, despite their antiferromagnetic coupling in the ground state, the Tb and Fe spins temporarily align ferromagnetically after excitation with an intense 55-fs laser pulse, after which they relax to their initial states due to the strong anisotropy in Tb.
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Affiliation(s)
- A R Khorsand
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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45
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Loh ZH, Leone SR. Capturing Ultrafast Quantum Dynamics with Femtosecond and Attosecond X-ray Core-Level Absorption Spectroscopy. J Phys Chem Lett 2013; 4:292-302. [PMID: 26283437 DOI: 10.1021/jz301910n] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recent technical advances in ultrafast laser sources enable the generation of femtosecond and attosecond soft X-ray pulses in tabletop laser setups as well as accelerator-based synchrotron and free-electron laser sources. These new light sources can be harnessed via pump-probe spectroscopy to elucidate ultrafast quantum dynamics in atoms, molecules, and condensed matter with unprecedented time resolution and chemical sensitivity. Employing such ultrashort pulses in transient X-ray absorption spectroscopy combines the unique advantages of core-level absorption probing of chemical environments and oxidation states with the ability to obtain ultimately freeze-frame snapshots of electronic and nuclear dynamics. In this Perspective, we provide an overview of the progress in applying the recently developed technique of femtosecond to attosecond time-resolved soft X-ray transient absorption spectroscopy to the study of ultrafast phenomena, including some of our own efforts to elucidate the interaction of intense laser pulses with atoms and molecules in the strong-field, nonperturbative limit. Possible avenues for future work are outlined.
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Affiliation(s)
- Zhi-Heng Loh
- †Division of Chemistry and Biological Chemistry, and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Stephen R Leone
- ‡Departments of Chemistry and Physics, University of California, Berkeley, California 94720, United States
- §Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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46
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Trabant C, Pontius N, Schierle E, Weschke E, Kachel T, Springholz G, Holldack K, Föhlisch A, Schüßler-Langeheine C. Time and momentum resolved resonant magnetic x-ray diffraction on EuTe. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134103014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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47
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Schuh T, Miyamachi T, Gerstl S, Geilhufe M, Hoffmann M, Ostanin S, Hergert W, Ernst A, Wulfhekel W. Magnetic excitations of rare earth atoms and clusters on metallic surfaces. NANO LETTERS 2012; 12:4805-4809. [PMID: 22906055 DOI: 10.1021/nl302250n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Magnetic anisotropy and magnetization dynamics of rare earth Gd atoms and dimers on Pt(111) and Cu(111) were investigated with inelastic tunneling spectroscopy. The spin excitation spectra reveal that giant magnetic anisotropies and lifetimes of the excited states of Gd are nearly independent of the supporting surfaces and the cluster size. In combination with theoretical calculations, we argue that the observed features are caused by strongly localized character of 4f electrons in Gd atoms and clusters.
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Affiliation(s)
- Tobias Schuh
- Karlsruhe Institute of Technology, Physikalisches Institut, Wolfgang-Gaede-Str. 1, 76131 Karlsruhe, Germany
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48
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Carley R, Döbrich K, Frietsch B, Gahl C, Teichmann M, Schwarzkopf O, Wernet P, Weinelt M. Femtosecond laser excitation drives ferromagnetic gadolinium out of magnetic equilibrium. PHYSICAL REVIEW LETTERS 2012; 109:057401. [PMID: 23006205 DOI: 10.1103/physrevlett.109.057401] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Indexed: 06/01/2023]
Abstract
The temporal evolution of the exchange-split Δ(2)-like Σ valence bands of the 4f-ferromagnet gadolinium after femtosecond laser excitation has been studied using angle-resolved photoelectron spectroscopy based on high-order harmonic generation. The ultrafast drop of the exchange splitting reflects the magnetic response seen in femtosecond magnetic dichroism experiments. However, while the minority valence band reacts immediately, the response of the majority counterpart is delayed by 1 picosecond and is only half as fast. These findings demonstrate that laser excitation drives the valence band structure out of magnetic equilibrium.
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49
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Ostler TA, Barker J, Evans RFL, Chantrell RW, Atxitia U, Chubykalo-Fesenko O, El Moussaoui S, Le Guyader L, Mengotti E, Heyderman LJ, Nolting F, Tsukamoto A, Itoh A, Afanasiev D, Ivanov BA, Kalashnikova AM, Vahaplar K, Mentink J, Kirilyuk A, Rasing T, Kimel AV. Ultrafast heating as a sufficient stimulus for magnetization reversal in a ferrimagnet. Nat Commun 2012; 3:666. [PMID: 22314362 DOI: 10.1038/ncomms1666] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 01/05/2012] [Indexed: 11/09/2022] Open
Abstract
The question of how, and how fast, magnetization can be reversed is a topic of great practical interest for the manipulation and storage of magnetic information. It is generally accepted that magnetization reversal should be driven by a stimulus represented by time-non-invariant vectors such as a magnetic field, spin-polarized electric current, or cross-product of two oscillating electric fields. However, until now it has been generally assumed that heating alone, not represented as a vector at all, cannot result in a deterministic reversal of magnetization, although it may assist this process. Here we show numerically and demonstrate experimentally a novel mechanism of deterministic magnetization reversal in a ferrimagnet driven by an ultrafast heating of the medium resulting from the absorption of a sub-picosecond laser pulse without the presence of a magnetic field.
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Affiliation(s)
- T A Ostler
- Department of Physics, University of York, York YO10 5DD, UK.
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50
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Carva K, Battiato M, Oppeneer PM. Ab Initio investigation of the Elliott-Yafet electron-phonon mechanism in laser-induced ultrafast demagnetization. PHYSICAL REVIEW LETTERS 2011; 107:207201. [PMID: 22181762 DOI: 10.1103/physrevlett.107.207201] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Indexed: 05/23/2023]
Abstract
The spin-flip (SF) Eliashberg function is calculated from first principles for ferromagnetic Ni to accurately establish the contribution of Elliott-Yafet electron-phonon SF scattering to Ni's femtosecond laser-driven demagnetization. This is used to compute the SF probability and demagnetization rate for laser-created thermalized as well as nonequilibrium electron distributions. Increased SF probabilities are found for thermalized electrons, but the induced demagnetization rate is extremely small. A larger demagnetization rate is obtained for nonequilibrium electron distributions, but its contribution is too small to account for femtosecond demagnetization.
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Affiliation(s)
- K Carva
- Department of Physics and Astronomy, Uppsala University, Sweden.
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