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Assefa TA, Seaberg MH, Reid AH, Shen L, Esposito V, Dakovski GL, Schlotter W, Holladay B, Streubel R, Montoya SA, Hart P, Nakahara K, Moeller S, Kevan SD, Fischer P, Fullerton EE, Colocho W, Lutman A, Decker FJ, Sinha SK, Roy S, Blackburn E, Turner JJ. The fluctuation-dissipation measurement instrument at the Linac Coherent Light Source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083902. [PMID: 36050107 DOI: 10.1063/5.0091297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
The development of new modes at x-ray free electron lasers has inspired novel methods for studying fluctuations at different energies and timescales. For closely spaced x-ray pulses that can be varied on ultrafast time scales, we have constructed a pair of advanced instruments to conduct studies targeting quantum materials. We first describe a prototype instrument built to test the proof-of-principle of resonant magnetic scattering using ultrafast pulse pairs. This is followed by a description of a new endstation, the so-called fluctuation-dissipation measurement instrument, which was used to carry out studies with a fast area detector. In addition, we describe various types of diagnostics for single-shot contrast measurements, which can be used to normalize data on a pulse-by-pulse basis and calibrate pulse amplitude ratios, both of which are important for the study of fluctuations in materials. Furthermore, we present some new results using the instrument that demonstrates access to higher momentum resolution.
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Affiliation(s)
- T A Assefa
- Stanford Institute for Materials and Energy Science, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M H Seaberg
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - A H Reid
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - L Shen
- Stanford Institute for Materials and Energy Science, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - V Esposito
- Stanford Institute for Materials and Energy Science, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - G L Dakovski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - W Schlotter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - B Holladay
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - R Streubel
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Physics Department, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - S A Montoya
- Center for Memory and Recording Research, University of California-San Diego, La Jolla, California 92093, USA
| | - P Hart
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - K Nakahara
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - S Moeller
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - S D Kevan
- Department of Physics, University of Oregon, Eugene, Oregon 97401, USA
| | - P Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Physics Department, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - E E Fullerton
- Center for Memory and Recording Research, University of California-San Diego, La Jolla, California 92093, USA
| | - W Colocho
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - A Lutman
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - F-J Decker
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - S K Sinha
- Department of Physics, University of California-San Diego, La Jolla, California 92093, USA
| | - S Roy
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - E Blackburn
- Division of Synchrotron Radiation Research, Department of Physics, Lund University, 22100 Lund, Sweden
| | - J J Turner
- Stanford Institute for Materials and Energy Science, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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2
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Sekiguchi F, Budzinauskas K, Padmanabhan P, Versteeg RB, Tsurkan V, Kézsmárki I, Foggetti F, Artyukhin S, van Loosdrecht PHM. Slowdown of photoexcited spin dynamics in the non-collinear spin-ordered phases in skyrmion host GaV 4S 8. Nat Commun 2022; 13:3212. [PMID: 35680864 PMCID: PMC9184521 DOI: 10.1038/s41467-022-30829-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 05/20/2022] [Indexed: 11/10/2022] Open
Abstract
Formation of magnetic order alters the character of spin excitations, which then affects transport properties. We investigate the photoexcited ultrafast spin dynamics in different magnetic phases in Néel-type skyrmion host GaV4S8 with time-resolved magneto-optical Kerr effect experiments. The coherent spin precession, whose amplitude is enhanced in the skyrmion-lattice phase, shows a signature of phase coexistence across the magnetic phase transitions. The incoherent spin relaxation dynamics slows down by a factor of two in the skyrmion-lattice/cycloid phases, indicating significant decrease in thermal conductivity triggered by a small change of magnetic field. The slow heat diffusion in the skyrmion-lattice/cycloid phases is attributed to the stronger magnon scattering off the domain walls formed in abundance in the skyrmion-lattice/cycloid phase. These results highlight the impact of spatial spin structure on the ultrafast heat transport in spin systems, providing a useful insight for the step toward ultrafast photocontrol of the magnets with novel spin orders. Skyrmions are a topological magnetic texture that have garnered considerable interest for various technological applications. Here, Sekiguchi et al. investigate the ultrafast optical response of GaV4S6, and find a significant reduction in the thermal conductivity in the skyrmion phase.
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Affiliation(s)
- Fumiya Sekiguchi
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany.
| | - Kestutis Budzinauskas
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany
| | - Prashant Padmanabhan
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany
| | - Rolf B Versteeg
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany
| | - Vladimir Tsurkan
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany.,Institute of Applied Physics, MD 2028, Chișinău, Republic of Moldova
| | - István Kézsmárki
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany
| | - Francesco Foggetti
- Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy.,Dipartimento di Fisica, Università di Genova, Via Dodecaneso, 33, 16146, Genova, Italy
| | - Sergey Artyukhin
- Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy
| | - Paul H M van Loosdrecht
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937, Köln, Germany.
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Mankowsky R, Sander M, Zerdane S, Vonka J, Bartkowiak M, Deng Y, Winkler R, Giorgianni F, Matmon G, Gerber S, Beaud P, Lemke HT. New insights into correlated materials in the time domain-combining far-infrared excitation with x-ray probes at cryogenic temperatures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:374001. [PMID: 34098537 DOI: 10.1088/1361-648x/ac08b5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Abstract
Modern techniques for the investigation of correlated materials in the time domain combine selective excitation in the THz frequency range with selective probing of coupled structural, electronic and magnetic degrees of freedom using x-ray scattering techniques. Cryogenic sample temperatures are commonly required to prevent thermal occupation of the low energy modes and to access relevant material ground states. Here, we present a chamber optimized for high-field THz excitation and (resonant) x-ray diffraction at sample temperatures between 5 and 500 K. Directly connected to the beamline vacuum and featuring both a Beryllium window and an in-vacuum detector, the chamber covers the full (2-12.7) keV energy range of the femtosecond x-ray pulses available at the Bernina endstation of the SwissFEL free electron laser. Successful commissioning experiments made use of the energy tunability to selectively track the dynamics of the structural, magnetic and orbital order of Ca2RuO4and Tb2Ti2O7at the Ru (2.96 keV) and Tb (7.55 keV)L-edges, respectively. THz field amplitudes up to 1.12 MV cm-1peak field were demonstrated and used to excite the samples at temperatures as low as 5 K.
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Affiliation(s)
| | | | | | - Jakub Vonka
- Paul Scherrer Institute, Villigen, Switzerland
| | | | - Yunpei Deng
- Paul Scherrer Institute, Villigen, Switzerland
| | - Rafael Winkler
- Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | | | - Guy Matmon
- Paul Scherrer Institute, Villigen, Switzerland
| | | | - Paul Beaud
- Paul Scherrer Institute, Villigen, Switzerland
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Kim H, Kim JG, Kim TW, Lee SJ, Nozawa S, Adachi SI, Yoon K, Kim J, Ihee H. Ultrafast structural dynamics of in-cage isomerization of diiodomethane in solution. Chem Sci 2020; 12:2114-2120. [PMID: 34163975 PMCID: PMC8179290 DOI: 10.1039/d0sc05108j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Despite extensive studies on the isomer species formed by photodissociation of haloalkanes in solution, the molecular structure of the precursor of the isomer, which is often assumed to be a vibrationally hot isomer formed from the radical pair, and its in-cage isomerization mechanism remain elusive. Here, the structural dynamics of CH2I2 upon 267 nm photoexcitation in methanol were probed with femtosecond X-ray solution scattering at an X-ray free-electron laser. The determined molecular structure of the transiently formed species that converts to the CH2I–I isomer has the I–I distance of 4.17 Å, which is longer than that of the isomer (3.15 Å) by more than 1.0 Å and the mean-squared displacement of 0.45 Å2, which is about 100 times larger than those of typical regular chemical bonds. These unusual structural characteristics are consistent with either a vibrationally hot form of the CH2I–I isomer or the loosely-bound radical pair (CH2I˙⋯I˙). The structural dynamics of in-cage isomerization of CH2I2 and the unusual structure of the loosely-bound isomer precursor were unveiled with femtosecond X-ray liquidography (solution scattering).![]()
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Affiliation(s)
- Hanui Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea .,KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
| | - Jong Goo Kim
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
| | - Tae Wu Kim
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
| | - Sang Jin Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea .,KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
| | - Shunsuke Nozawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan.,Department of Materials Structure Science, School of High Energy Accelerator Science, The Graduate University for Advanced Studies Tsukuba Ibaraki 305-0801 Japan
| | - Shin-Ichi Adachi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan.,Department of Materials Structure Science, School of High Energy Accelerator Science, The Graduate University for Advanced Studies Tsukuba Ibaraki 305-0801 Japan
| | - Kihwan Yoon
- Department of Chemistry, The Catholic University of Korea Bucheon 14662 Republic of Korea
| | - Joonghan Kim
- Department of Chemistry, The Catholic University of Korea Bucheon 14662 Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea .,KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
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5
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Padmanabhan P, Sekiguchi F, Versteeg RB, Slivina E, Tsurkan V, Bordács S, Kézsmárki I, van Loosdrecht PHM. Optically Driven Collective Spin Excitations and Magnetization Dynamics in the Néel-type Skyrmion Host GaV_{4}S_{8}. PHYSICAL REVIEW LETTERS 2019; 122:107203. [PMID: 30932635 DOI: 10.1103/physrevlett.122.107203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 02/08/2019] [Indexed: 06/09/2023]
Abstract
GaV_{4}S_{8} is a multiferroic semiconductor hosting magnetic cycloid (Cyc) and Néel-type skyrmion lattice (SkL) phases with a broad region of thermal and magnetic stability. Here, we use time-resolved magneto-optical Kerr spectroscopy to show the coherent generation of collective spin excitations in the Cyc and SkL phases. Our micromagnetic simulations reveal that these are driven by an optically induced modulation of uniaxial anisotropy. Our results shed light on spin dynamics in anisotropic materials hosting skyrmions and pave a new pathway for the optical manipulation of their magnetic order.
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Affiliation(s)
- P Padmanabhan
- Physics Institute II, University of Cologne, 50937 Cologne, Germany
| | - F Sekiguchi
- Physics Institute II, University of Cologne, 50937 Cologne, Germany
| | - R B Versteeg
- Physics Institute II, University of Cologne, 50937 Cologne, Germany
| | - E Slivina
- Physics Institute II, University of Cologne, 50937 Cologne, Germany
| | - V Tsurkan
- Institute of Applied Physics, MD 2028, Chisinau, Republic of Moldova
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - S Bordács
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary
- Hungarian Academy of Sciences, Premium Postdoctoral Program, 1051 Budapest, Hungary
| | - I Kézsmárki
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary
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6
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Versteeg RB, Zhu J, Padmanabhan P, Boguschewski C, German R, Goedecke M, Becker P, van Loosdrecht PHM. A tunable time-resolved spontaneous Raman spectroscopy setup for probing ultrafast collective excitation and quasiparticle dynamics in quantum materials. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2018; 5:044301. [PMID: 30057929 PMCID: PMC6051769 DOI: 10.1063/1.5037784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/29/2018] [Indexed: 05/12/2023]
Abstract
We present a flexible and efficient ultrafast time-resolved spontaneous Raman spectroscopy setup to study collective excitation and quasi-particle dynamics in quantum materials. The setup has a broad energy tuning range extending from the visible to near infrared spectral regions for both the pump excitation and Raman probe pulses. Additionally, the balance between energy and time-resolution can be controlled. A high light collecting efficiency is realized by high numerical aperture collection optics and a high-throughput flexible spectrometer. We demonstrate the functionality of the setup with a study of the zone-center longitudinal optical phonon and hole continuum dynamics in silicon and discuss the role of the Raman tensor in time-resolved Raman scattering. In addition, we show an evidence for unequal phonon softening rates at different high symmetry points in the Brillouin zone of silicon by means of detecting pump-induced changes in the two-phonon overtone spectrum. Demagnetization dynamics in the helimagnet Cu2OSeO3 is studied by observing softening and broadening of a magnon after photo-excitation, underlining the unique power of measuring transient dynamics in the frequency domain, and the feasibility to study phase transitions in quantum materials.
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Affiliation(s)
- R. B. Versteeg
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - J. Zhu
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - P. Padmanabhan
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - C. Boguschewski
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - R. German
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - M. Goedecke
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - P. Becker
- Abteilung Kristallographie, Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicher Straße 49b, D-50674 Köln, Germany
| | - P. H. M. van Loosdrecht
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
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