1
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Sun S, Gu B, Hu H, Lu L, Tang D, Chernyak VY, Li X, Mukamel S. Direct Probe of Conical Intersection Photochemistry by Time-Resolved X-ray Magnetic Circular Dichroism. J Am Chem Soc 2024; 146:19863-19873. [PMID: 38989850 DOI: 10.1021/jacs.4c03033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
The direct probing of photochemical dynamics by detecting the electronic coherence generated during passage through conical intersections is an intriguing challenge. The weak coherence signal and the difficulty in preparing purely excited wave packets that exclude coherence from other sources make it experimentally challenging. We propose to use time-resolved X-ray magnetic circular dichroism to probe the wave packet dynamics around the conical intersection. The magnetic field amplifies the relative strength of the electronic coherence signal compared to populations through the magnetic field response anisotropy. More importantly, since the excited state relaxation through conical intersections involves a change of parity, the magnetic coupling matches the symmetry of the response function with the electronic coherence, making the coherence signal only sensitive to the conical intersection induced coherence and excludes the pump pulse induced coherence between the ground state and excited state. In this theoretical study, we apply this technique to the photodissociation dynamics of a pyrrole molecule and demonstrate its capability of probing electronic coherence at a conical intersection as well as population transfer. We demonstrate that a magnetic field can be effectively used to extract novel information about electron and nuclear molecular dynamics.
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Affiliation(s)
- Shichao Sun
- Department of Chemistry, University of California, Irvine, California 92697, United states
- Departmnet of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - Bing Gu
- Department of Chemistry and Department of Physics, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Hang Hu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Lixin Lu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Diandong Tang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Vladimir Y Chernyak
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
- Department of Mathematics, Wayne State University, 656 West Kirby, Detroit, Michigan 48202, United States
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697, United states
- Departmnet of Physics and Astronomy, University of California, Irvine, California 92697, United States
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2
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Okamoto J, Wang RP, Chu YY, Shiu HW, Singh A, Huang HY, Mou CY, Teh S, Jeng HT, Du K, Xu X, Cheong SW, Du CH, Chen CT, Fujimori A, Huang DJ. Giant X-Ray Circular Dichroism in a Time-Reversal Invariant Antiferromagnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309172. [PMID: 38391035 DOI: 10.1002/adma.202309172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 02/09/2024] [Indexed: 02/24/2024]
Abstract
X-ray circular dichroism, arising from the contrast in X-ray absorption between opposite photon helicities, serves as a spectroscopic tool to measure the magnetization of ferromagnetic materials and identify the handedness of chiral crystals. Antiferromagnets with crystallographic chirality typically lack X-ray magnetic circular dichroism because of time-reversal symmetry, yet exhibit weak X-ray natural circular dichroism. Here, the observation of giant natural circular dichroism in the Ni L3-edge X-ray absorption of Ni3TeO6 is reported, a polar and chiral antiferromagnet with effective time-reversal symmetry. To unravel this intriguing phenomenon, a phenomenological model is proposed that classifies the movement of photons in a chiral crystal within the same symmetry class as that of a magnetic field. The coupling of X-ray polarization with the induced magnetization yields giant X-ray natural circular dichroism, revealing typical ferromagnetic behaviors allowed by the symmetry in an antiferromagnet, i.e., the altermagnetism of Ni3TeO6. The findings provide evidence for the interplay between magnetism and crystal chirality in natural optical activity. Additionally, the first example of a new class of magnetic materials exhibiting circular dichroism is established with time-reversal symmetry.
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Affiliation(s)
- Jun Okamoto
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Ru-Pan Wang
- Department of Physics, University of Hamburg, Luruper Chaussee 149, G610, 22761, Hamburg, Germany
| | - Yen-Yi Chu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Hung-Wei Shiu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Amol Singh
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Hsiao-Yu Huang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chung-Yu Mou
- Center for Quantum Science and Technology and Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Sukhito Teh
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Kai Du
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Xianghan Xu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Chao-Hung Du
- Department of Physics, Tamkang University, Tamsui, 251, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Atsushi Fujimori
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
- Center for Quantum Science and Technology and Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Department of Physics, University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan
| | - Di-Jing Huang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30093, Taiwan
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3
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N'Diaye A, Bordage A, Nataf L, Baudelet F, Rivière E, Bleuzen A. Interplay between transition-metal K-edge XMCD, slight structural distortions and magnetism in a series of trimetallic (Co xNi (1-x)) 4[Fe(CN) 6] 3/8 Prussian blue analogues. Phys Chem Chem Phys 2024; 26:15576-15586. [PMID: 38757724 DOI: 10.1039/d3cp04749k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
The magnetic properties of a series of trimetallic (Co,Ni)Fe Prussian blue analogues (PBAs) were investigated by SQUID magnetometry and X-ray magnetic circular dichroism (XMCD) at the three transition metal (TM) K-edges. In turn, the PBA trimetallic series was used as a tool in order to better understand the information contained in TM K-edge XMCD and particularly the chemical nature of the probed species (extended sub-lattice or localized entities). The results show that the magnetic behavior of the compounds is dictated by competing exchange interactions between the Co-Fe and Ni-Fe pairs, without spin frustration. They also show that XMCD at the TM K-edge is a local atomic probe of the element at the N side of the cyanide bridge and a local probe of the absorbing atom and its first magnetic neighbors on the C side of the bridge. At last, XMCD at the TM K-edge turns out to be highly sensitive to very small structural distortions.
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Affiliation(s)
- Adama N'Diaye
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, 91405 Orsay, France.
| | - Amélie Bordage
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, 91405 Orsay, France.
| | - Lucie Nataf
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, BP 48, 91192 Gif sur Yvette, France
| | - François Baudelet
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, 91405 Orsay, France.
| | - Anne Bleuzen
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, 91405 Orsay, France.
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4
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Brooks NJ, Dorney KM, Ellis J, Denton AE, Gentry C, Ryan SA, Nguyen QLD, Morrill DW, Kapteyn HC, Murnane MM. High-harmonic spin-shearing interferometry for spatially resolved EUV magneto-optical spectroscopy. OPTICS EXPRESS 2024; 32:19076-19087. [PMID: 38859051 DOI: 10.1364/oe.521669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/30/2024] [Indexed: 06/12/2024]
Abstract
We present a method for achieving hyperspectral magnetic imaging in the extreme ultraviolet (EUV) region based on high-harmonic generation (HHG). By interfering two mutually coherent orthogonally-polarized and laterally-sheared HHG sources, we create an EUV illumination beam with spatially-dependent ellipticity. By placing a magnetic sample in the beamline and sweeping the relative time delay between the two sources, we record a spatially resolved interferogram that is sensitive to the EUV magnetic circular dichroism of the sample. This image contains the spatially-resolved magneto-optical response of the sample at each harmonic order, and can be used to measure the magnetic properties of spatially inhomogeneous magnetic samples.
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Urrestarazu Larrañaga J, Sisodia N, Guedas R, Pham VT, Di Manici I, Masseboeuf A, Garello K, Disdier F, Fernandez B, Wintz S, Weigand M, Belmeguenai M, Pizzini S, Sousa RC, Buda-Prejbeanu LD, Gaudin G, Boulle O. Electrical Detection and Nucleation of a Magnetic Skyrmion in a Magnetic Tunnel Junction Observed via Operando Magnetic Microscopy. NANO LETTERS 2024; 24:3557-3565. [PMID: 38499397 DOI: 10.1021/acs.nanolett.4c00316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Magnetic skyrmions are topological spin textures which are envisioned as nanometer scale information carriers in magnetic memory and logic devices. The recent demonstrations of room temperature skyrmions and their current induced manipulation in ultrathin films were first steps toward the realization of such devices. However, important challenges remain regarding the electrical detection and the low-power nucleation of skyrmions, which are required for the read and write operations. Here, we demonstrate, using operando magnetic microscopy experiments, the electrical detection of a single magnetic skyrmion in a magnetic tunnel junction (MTJ) and its nucleation and annihilation by gate voltage via voltage control of magnetic anisotropy. The nucleated skyrmion can be manipulated by both gate voltages and external magnetic fields, leading to tunable intermediate resistance states. Our results unambiguously demonstrate the readout and voltage controlled write operations in a single MTJ device, which is a major milestone for low power skyrmion based technologies.
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Affiliation(s)
| | - Naveen Sisodia
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Rodrigo Guedas
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Van Tuong Pham
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Ilaria Di Manici
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Aurélien Masseboeuf
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Kevin Garello
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Florian Disdier
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Bruno Fernandez
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Sebastian Wintz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
| | - Markus Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
| | - Mohamed Belmeguenai
- LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France
| | - Stefania Pizzini
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Ricardo C Sousa
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | | | - Gilles Gaudin
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Olivier Boulle
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
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6
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Gallardo R, Weigand M, Schultheiss K, Kakay A, Mattheis R, Raabe J, Schütz G, Deac A, Lindner J, Wintz S. Coherent Magnons with Giant Nonreciprocity at Nanoscale Wavelengths. ACS NANO 2024. [PMID: 38314709 PMCID: PMC10883124 DOI: 10.1021/acsnano.3c08390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Nonreciprocal wave propagation arises in systems with broken time-reversal symmetry and is key to the functionality of devices, such as isolators or circulators, in microwave, photonic, and acoustic applications. In magnetic systems, collective wave excitations known as magnon quasiparticles have so far yielded moderate nonreciprocities, mainly observed by means of incoherent thermal magnon spectra, while their occurrence as coherent spin waves (magnon ensembles with identical phase) is yet to be demonstrated. Here, we report the direct observation of strongly nonreciprocal propagating coherent spin waves in a patterned element of a ferromagnetic bilayer stack with antiparallel magnetic orientations. We use time-resolved scanning transmission X-ray microscopy (TR-STXM) to directly image the layer-collective dynamics of spin waves with wavelengths ranging from 5 μm down to 100 nm emergent at frequencies between 500 MHz and 5 GHz. The experimentally observed nonreciprocity factor of these counter-propagating waves is greater than 10 with respect to both group velocities and specific wavelengths. Our experimental findings are supported by the results from an analytic theory, and their peculiarities are further discussed in terms of caustic spin-wave focusing.
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Affiliation(s)
- Rodolfo Gallardo
- Universidad Técnica Federico Santa María, 2390123 Valparaíso, Chile
| | | | - Katrin Schultheiss
- Helmholtz-Zentrum Dresden-Rossendorf, Insitute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - Attila Kakay
- Helmholtz-Zentrum Dresden-Rossendorf, Insitute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - Roland Mattheis
- Leibniz Institut für Photonische Technologien, 07745 Jena, Germany
| | - Jörg Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - Alina Deac
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden High Magnetic Field Laboratory, 01328 Dresden, Germany
| | - Jürgen Lindner
- Helmholtz-Zentrum Dresden-Rossendorf, Insitute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum Berlin, 12489 Berlin, Germany
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
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7
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Szpytma M, Ślęzak M, Janus W, Nayyef H, Ślęzak T, Mandziak A, Zając M, Wilgocka-Ślęzak D, Menteş TO, Jugovac M, Locatelli A, Kozioł-Rachwał A. Transfer of magnetic anisotropy in epitaxial Co/NiO/Fe trilayers. Sci Rep 2024; 14:1680. [PMID: 38243038 PMCID: PMC10798992 DOI: 10.1038/s41598-024-51896-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 01/10/2024] [Indexed: 01/21/2024] Open
Abstract
The magnetic properties of Co(10 Å)/NiO(40 Å)/Fe trilayer epitaxially grown on W(110) substrate were investigated with use of x-ray magnetic linear dichroism (XMLD) and x-ray magnetic circular dichroism (XMCD). We showed that magnetic anisotropy of Fe film that can be controlled by a thickness-driven spin reorientation transition is transferred via interfacial exchange coupling not only to NiO layer but further to ferromagnetic Co overlayer as well. Similarly, a temperature driven spin reorientation of Fe sublayer induces a reorientation of NiO spin orientation and simultaneous switching of the Co magnetization direction. Finally, by element specific XMCD and XMLD magnetic hysteresis loop measurements we proved that external magnetic field driven reorientation of Fe and Co magnetizations as well as NiO Néel vector are strictly correlated and magnetic anisotropy fields of Fe and Co sublayers are identical despite the different crystal structures.
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Affiliation(s)
- M Szpytma
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland.
| | - M Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - W Janus
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - H Nayyef
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - T Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
| | - A Mandziak
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Krakow, Poland
| | - M Zając
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Krakow, Poland
| | - D Wilgocka-Ślęzak
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - T O Menteş
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - M Jugovac
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - A Locatelli
- Elettra - Sincrotrone Trieste, Basovizza, Trieste, Italy
| | - A Kozioł-Rachwał
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, Krakow, Poland
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8
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Borchert M, Braenzel J, Gnewkow R, Lunin L, Sidiropoulos T, Tümmler J, Will I, Noll T, Reichel O, Rohloff D, Erko A, Krist T, von Korff Schmising C, Pfau B, Eisebitt S, Stiel H, Schick D. Versatile tabletop setup for picosecond time-resolved resonant soft-x-ray scattering and spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:063102. [PMID: 37862537 DOI: 10.1063/5.0151613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/31/2023] [Indexed: 10/22/2023]
Abstract
We present a laser-driven, bright, and broadband (50 to 1500 eV) soft-x-ray plasma source with <10 ps pulse duration. This source is employed in two complementary, laboratory-scale beamlines for time-resolved, magnetic resonant scattering and spectroscopy, as well as near-edge x-ray absorption fine-structure (NEXAFS) spectroscopy. In both beamlines, dedicated reflection zone plates (RZPs) are used as single optical elements to capture, disperse, and focus the soft x rays, reaching resolving powers up to E/ΔE > 1000, with hybrid RZPs at the NEXAFS beamline retaining a consistent E/ΔE > 500 throughout the full spectral range, allowing for time-efficient data acquisition. We demonstrate the versatility and performance of our setup by a selection of soft-x-ray spectroscopy and scattering experiments, which so far have not been possible on a laboratory scale. Excellent data quality, combined with experimental flexibility, renders our approach a true alternative to large-scale facilities, such as synchrotron-radiation sources and free-electron lasers.
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Affiliation(s)
- Martin Borchert
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Julia Braenzel
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Richard Gnewkow
- Helmholtz-Zentrum Berlin, 12489 Berlin, Germany
- Technische Universität Berlin, Institut für Optik und Atomare Physik, 10623 Berlin, Germany
- Berlin Laboratory for Innovative X-ray Technologies (BLiX), 10623 Berlin, Germany
| | - Leonid Lunin
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | | | - Johannes Tümmler
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Ingo Will
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Tino Noll
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Oliver Reichel
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Dirk Rohloff
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | | | - Thomas Krist
- NOB Nano Optics Berlin GmbH, 10627 Berlin, Germany
| | | | - Bastian Pfau
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Stefan Eisebitt
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
- Technische Universität Berlin, Institut für Optik und Atomare Physik, 10623 Berlin, Germany
| | - Holger Stiel
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
- Berlin Laboratory for Innovative X-ray Technologies (BLiX), 10623 Berlin, Germany
| | - Daniel Schick
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
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9
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Finizio S, Bailey JB, Olsthoorn B, Raabe J. Periodogram-Based Detection of Unknown Frequencies in Time-Resolved Scanning Transmission X-ray Microscopy. ACS NANO 2022; 16:21071-21078. [PMID: 36512505 DOI: 10.1021/acsnano.2c08874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Pump-probe time-resolved imaging is a powerful technique that enables the investigation of dynamical processes. Signal-to-noise and sampling rate restrictions normally require that cycles of an excitation are repeated many times with the final signal reconstructed using a reference. However, this approach imposes restrictions on the types of dynamical processes that can be measured, namely, that they are phase locked to a known external signal (e.g., a driven oscillation or impulse). This rules out many interesting processes such as auto-oscillations and spontaneously forming populations, e.g., condensates. In this work we present a method for time-resolved imaging, based on the Schuster periodogram, that allows for the reconstruction of dynamical processes where the intrinsic frequency is not known. In our case we use time of arrival detection of X-ray photons to reconstruct magnetic dynamics without using a priori information on the dynamical frequency. This proof-of-principle demonstration will allow for the extension of pump-probe time-resolved imaging to the important class of processes where the dynamics are not locked to a known external signal and in its presented formulation can be readily adopted for X-ray imaging and also adapted for wider use.
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Affiliation(s)
| | - Joe Bilko Bailey
- Paul Scherrer Institut, 5232Villigen PSI, Switzerland
- Institut de Physique, EPFL, 1015Lausanne, Switzerland
| | - Bart Olsthoorn
- Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, SE-106 91Stockholm, Sweden
| | - Jörg Raabe
- Paul Scherrer Institut, 5232Villigen PSI, Switzerland
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10
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Ovchinnikova EN, Kozlovskaya KA, Dmitrienko VE, Oreshko AP. The Use of Circularly Polarized Synchrotron Radiation in Diffraction and Spectral Studies of Noncentrosymmetric Crystals. CRYSTALLOGR REP+ 2022. [DOI: 10.1134/s1063774522060207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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11
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N’Diaye A, Bordage A, Nataf L, Baudelet F, Rivière E, Bleuzen A. Interplay between Transition-Metal K-edge XMCD and Magnetism in Prussian Blue Analogs. ACS OMEGA 2022; 7:36366-36378. [PMID: 36278067 PMCID: PMC9583310 DOI: 10.1021/acsomega.2c04049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/25/2022] [Indexed: 06/16/2023]
Abstract
To disentangle the information contained in transition-metal K-edge X-ray magnetic circular dichroism (XMCD), two series of Prussian blue analogs (PBAs) were investigated as model compounds. The number of 3d electrons and the magnetic orbitals have been varied on both sites of the bimetallic cyanide polymer by combining with the hexacyanoferrate or the hexacyanochromate entities' various divalent metal ions A2+ (Mn2+, Fe2+, Co2+, Ni2+, and Cu2+). These PBA were studied by Fe and Cr X-ray absorption spectroscopy and XMCD. The results, compared to those obtained at the A K-edges in a previous work, show that transition-metal K-edge XMCD is very sensitive to orbital symmetry and can therefore give valuable information on the local structure of the magnetic centers. Expressions of the intensity of the main 1s → 4p contribution to the signal are proposed for all K-edges and all compounds. The results pave the way toward a new tool for molecular materials able to give access to valuable information on the local orientation of the magnetic moments or to better understand the role of 4p orbitals involved in their magnetic properties.
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Affiliation(s)
- Adama N’Diaye
- Institut
de Chimie Moléculaire et des Matériaux d’Orsay,
CNRS, Université Paris-Saclay, 91405Orsay, France
| | - Amélie Bordage
- Institut
de Chimie Moléculaire et des Matériaux d’Orsay,
CNRS, Université Paris-Saclay, 91405Orsay, France
| | - Lucie Nataf
- Synchrotron
SOLEIL, L’Orme des Merisiers, St Aubin, BP 48, F-91192Gif sur Yvette, France
| | - François Baudelet
- Synchrotron
SOLEIL, L’Orme des Merisiers, St Aubin, BP 48, F-91192Gif sur Yvette, France
| | - Eric Rivière
- Institut
de Chimie Moléculaire et des Matériaux d’Orsay,
CNRS, Université Paris-Saclay, 91405Orsay, France
| | - Anne Bleuzen
- Institut
de Chimie Moléculaire et des Matériaux d’Orsay,
CNRS, Université Paris-Saclay, 91405Orsay, France
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12
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Bordage A, N’Diaye A, Bleuzen A. Prussian Blue analogs and transition metal K-edge XMCD: a longstanding friendship. CR CHIM 2022. [DOI: 10.5802/crchim.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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TimeMaxyne: A Shot-Noise Limited, Time-Resolved Pump-and-Probe Acquisition System Capable of 50 GHz Frequencies for Synchrotron-Based X-ray Microscopy. CRYSTALS 2022. [DOI: 10.3390/cryst12081029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
With the advent of modern synchrotron sources, X-ray microscopy was developed as a vigorous tool for imaging material structures with element-specific, structural, chemical and magnetic sensitivity at resolutions down to 25 nm and below. Moreover, the X-ray time structure emitted from the synchrotron source (short bunches of less than 100 ps width) provides a unique possibility to combine high spatial resolution with high temporal resolution for periodic processes by means of pump-and-probe measurements. To that end, TimeMaxyne was developed as a time-resolved acquisition setup for the scanning X-ray microscope MAXYMUS at the BESSY II synchrotron in order to perform high precision, high throughput pump-and-probe imaging. The setup combines a highly sensitive single photon detector, a real time photon sorting system and a dedicated synchronization scheme for aligning various types of sample excitations of up to 50 GHz bandwidth to the photon probe. Hence, TimeMaxyne has been demonstrated to be capable of shot-noise limited, time-resolved imaging, at time resolutions of 50 ps and below, only limited by the X-ray pulse widths of the synchrotron.
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14
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MacKinnon CR, Zeissler K, Finizio S, Raabe J, Marrows CH, Mercer T, Bissell PR, Lepadatu S. Collective skyrmion motion under the influence of an additional interfacial spin-transfer torque. Sci Rep 2022; 12:10786. [PMID: 35750744 PMCID: PMC9232533 DOI: 10.1038/s41598-022-14969-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/15/2022] [Indexed: 11/26/2022] Open
Abstract
Here we study the effect of an additional interfacial spin-transfer torque, as well as the well-established spin–orbit torque and bulk spin-transfer torque, on skyrmion collections—group of skyrmions dense enough that they are not isolated from one another—in ultrathin heavy metal/ferromagnetic multilayers, by comparing modelling with experimental results. Using a skyrmion collection with a range of skyrmion diameters and landscape disorder, we study the dependence of the skyrmion Hall angle on diameter and velocity, as well as the velocity as a function of diameter. We show that inclusion of the interfacial spin-transfer torque results in reduced skyrmion Hall angles, with values close to experimental results. We also show that for skyrmion collections the velocity is approximately independent of diameter, in marked contrast to the motion of isolated skyrmions, as the group of skyrmions move together at an average group velocity. Moreover, the calculated skyrmion velocities are comparable to those obtained in experiments when the interfacial spin-transfer torque is included. Our results thus show the significance of the interfacial spin-transfer torque in ultrathin magnetic multilayers, which helps to explain the low skyrmion Hall angles and velocities observed in experiment. We conclude that the interfacial spin-transfer torque should be considered in numerical modelling for reproduction of experimental results.
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Affiliation(s)
- Callum R MacKinnon
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
| | - Katharina Zeissler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.,Bragg Center for Materials Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Christopher H Marrows
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.,Bragg Center for Materials Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Tim Mercer
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Philip R Bissell
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Serban Lepadatu
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
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15
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N'Diaye A, Bordage A, Nataf L, Baudelet F, Rivière E, Bleuzen A. Toward Quantitative Magnetic Information from Transition Metal K-Edge XMCD of Prussian Blue Analogs. Inorg Chem 2022; 61:6326-6336. [PMID: 35414167 DOI: 10.1021/acs.inorgchem.2c00637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two series of Prussian blue analogs (PBA) were used as model compounds in order to disentangle the information contained in X-ray magnetic circular dichroism (XMCD) at the K-edges of transition metals. The number of 3d electrons on one site of the bimetallic cyanide polymer has been varied by associating to the [Fe(CN)6]3- or the [Cr(CN)6]3- precursors various divalent metal ions A2+ (Mn2+, Fe2+, Co2+, Ni2+, and Cu2+). The compounds were studied by X-ray diffraction and SQUID magnetometry, as well as by X-ray absorption spectroscopy and XMCD at the K-edges of the A2+ transition metal ion. The study shows that the 1s → 4p contribution to the A K-edge XMCD signal can be related to the electronic structure and the magnetic behavior of the probed A2+ ion: the shape of the signal to the filling of the 3d orbitals, the sign of the signal to the direction of the magnetic moment with respect to the applied magnetic field, the intensity of the signal to the total spin number SA, and the area under curve to the Curie constant CA. The whole study hence demonstrates that PBAs are particularly well-adapted for understanding the information contained in the transition metals K-edge XMCD signals. It also offers new perspectives toward the full disentangling of the information contained in these signals and access to new insights into materials magnetic properties.
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Affiliation(s)
- Adama N'Diaye
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Amélie Bordage
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Lucie Nataf
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, F-91192 Gif sur Yvette, France
| | - François Baudelet
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, F-91192 Gif sur Yvette, France
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Anne Bleuzen
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
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16
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Amplification of elliptically polarized sub-femtosecond pulses in neon-like X-ray laser modulated by an IR field. Sci Rep 2022; 12:6204. [PMID: 35418583 PMCID: PMC9008065 DOI: 10.1038/s41598-022-09701-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/28/2022] [Indexed: 11/09/2022] Open
Abstract
Amplification of attosecond pulses produced via high harmonic generation is a formidable problem since none of the amplifiers can support the corresponding PHz bandwidth. Producing the well defined polarization state common for a set of harmonics required for formation of the circularly/elliptically polarized attosecond pulses (which are on demand for dynamical imaging and coherent control of the spin flip processes) is another big challenge. In this work we show how both problems can be tackled simultaneously on the basis of the same platform, namely, the plasma-based X-ray amplifier whose resonant transition frequency is modulated by an infrared field.
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17
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Groß F, Träger N, Schulz F, Weigand M, Dippon T, Gräfe J. A high frequency builder software for arbitrary radio frequency signals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:034704. [PMID: 35364984 DOI: 10.1063/5.0082934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
While the frequencies accessible by signal generators steadily rise, the synthesization of complex and arbitrary waveforms with high frequency components remains challenging, especially when restricted by an external reference clock. In this article, we present a comprehensive software package combined with state-of-the-art hardware as a solution for the generation of highly sampled, arbitrary radio frequency waveforms. The software can be used to conduct both synchronous and heterodyne pump-probe experiments due to a variety of different synchronization modules. While both kinds of modules allow for standard waveforms, such as sines, pulses, and bursts, as well as any arbitrary signal, the heterodyne modules additionally are not restricted by the reference clock frequency. Both the output and the synchronization module can be adapted to support additional measurement devices. Due to the modular software structure, individual classes can be exchanged while maintaining all functionalities. The software provides a user friendly graphical interface that allows us to compose, save, and load complex arbitrary waveforms within only a few steps. The frequency selectivity provided by the software-hardware combination allows us to directly target specific excitation states of physical systems. Conducting a heterodyne scanning transmission x-ray microscopy experiment, we are able to demonstrate the capabilities of the software when paired with a high sample rate arbitrary waveform generator. The heterodyne synchronization modules allow for unlimited flexibility leveraging arbitrary waveform generation to their full power. By solving the challenges of synthesizing highly complex electromagnetic waves, the software enables a large variety of experiments to be performed more conveniently.
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Affiliation(s)
- Felix Groß
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Nick Träger
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Frank Schulz
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Markus Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | | | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
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18
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Junghoefer T, Calzolari A, Baev I, Glaser M, Ciccullo F, Giangrisostomi E, Ovsyannikov R, Kielgast F, Nissen M, Schwarz J, Gallagher NM, Rajca A, Martins M, Casu MB. Magnetic behavior in metal-free radical thin films. Chem 2021. [DOI: 10.1016/j.chempr.2021.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Readout of an antiferromagnetic spintronics system by strong exchange coupling of Mn 2Au and Permalloy. Nat Commun 2021; 12:6539. [PMID: 34764314 PMCID: PMC8586249 DOI: 10.1038/s41467-021-26892-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 10/22/2021] [Indexed: 11/09/2022] Open
Abstract
In antiferromagnetic spintronics, the read-out of the staggered magnetization or Néel vector is the key obstacle to harnessing the ultra-fast dynamics and stability of antiferromagnets for novel devices. Here, we demonstrate strong exchange coupling of Mn2Au, a unique metallic antiferromagnet that exhibits Néel spin-orbit torques, with thin ferromagnetic Permalloy layers. This allows us to benefit from the well-established read-out methods of ferromagnets, while the essential advantages of antiferromagnetic spintronics are only slightly diminished. We show one-to-one imprinting of the antiferromagnetic on the ferromagnetic domain pattern. Conversely, alignment of the Permalloy magnetization reorients the Mn2Au Néel vector, an effect, which can be restricted to large magnetic fields by tuning the ferromagnetic layer thickness. To understand the origin of the strong coupling, we carry out high resolution electron microscopy imaging and we find that our growth yields an interface with a well-defined morphology that leads to the strong exchange coupling.
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20
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Liu Z, Deng B, Deng H, Liu B. Numerical study of transverse position monitor and compensation for x-ray polarization diagnosis. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:113104. [PMID: 34852524 DOI: 10.1063/5.0054804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
Diagnosing free electron laser (FEL) polarization is critical for polarization-modulated research such as x-ray FEL diffraction imaging and probing material magnetism. In an electron time-of-flight (eTOF) polarimeter, the flight time and angular distribution of photoelectrons were designed based on x-ray polarimetry for on-site diagnosis. However, the transverse position of x-ray FEL pulses introduces error into the measured photoelectron angular distribution. This work, thus, proposes a method of compensating transverse position jitters for the polarization by the eTOF polarimeter itself without an external x-ray beam-position monitor. A comprehensive numerical model is developed to demonstrate the feasibility of the compensation method, and the results reveal that a spatial resolution of 20 μm and a polarity improved by 0.02 are possible with fully polarized FEL pulses. The impact of FEL pulses and a method to calibrate their linearity are also discussed.
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Affiliation(s)
- Zipeng Liu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 201800 Shanghai, China
| | - Bangjie Deng
- School of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an, 710049 Shaanxi, China
| | - Haixiao Deng
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
| | - Bo Liu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
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21
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Superconducting imprint of magnetic textures in ferromagnets with perpendicular magnetic anisotropy. Sci Rep 2021; 11:20788. [PMID: 34675339 PMCID: PMC8531309 DOI: 10.1038/s41598-021-99963-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 09/28/2021] [Indexed: 11/28/2022] Open
Abstract
Research on proximity effects in superconductor/ferromagnetic hybrids has most often focused on how superconducting properties are affected—and can be controlled—by the effects of the ferromagnet’s exchange or magnetic fringe fields. The opposite, namely the possibility to craft, tailor and stabilize the magnetic texture in a ferromagnet by exploiting superconducting effects, has been more seldom explored. Here we show that the magnetic flux trapped in high-temperature superconducting YBa2Cu3O7-δ microstructures can be used to modify the magnetic reversal of a hard ferromagnet—a cobalt/platinum multilayer with perpendicular magnetic anisotropy—and to imprint unusual magnetic domain distributions in a controlled manner via the magnetic field history. The domain distributions imprinted in the superconducting state remain stable, in absence of an external magnetic field, even after increasing the temperature well above the superconducting critical temperature, at variance to what has been observed for soft ferromagnets with in-plane magnetic anisotropy. This opens the possibility of having non-trivial magnetic configuration textures at room temperature after being tailored below the superconducting transition temperature. The observed effects are well explained by micromagnetic simulations that demonstrate the role played by the magnetic field from the superconductor on the nucleation, propagation, and stabilization of magnetic domains.
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22
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Finizio S, Watts B, Raabe J. Why is my image noisy? A look into the terms contributing to a time-resolved X-ray microscopy image. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1146-1158. [PMID: 34212878 DOI: 10.1107/s1600577521004240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/20/2021] [Indexed: 06/13/2023]
Abstract
Through Monte Carlo simulations, we investigate how various experimental parameters can influence the quality of time-resolved scanning transmission X-ray microscopy images. In particular, the effect of the X-ray photon flux, of the thickness of the investigated samples, and of the frequency of the dynamical process under investigation on the resulting time-resolved image are investigated. The ideal sample and imaging conditions that allow for an optimal image quality are then identifed.
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Affiliation(s)
- Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Benjamin Watts
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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23
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N'Diaye A, Bordage A, Nataf L, Baudelet F, Moreno T, Bleuzen A. A cookbook for the investigation of coordination polymers by transition metal K-edge XMCD. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1127-1136. [PMID: 34212876 DOI: 10.1107/s1600577521004884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/08/2021] [Indexed: 06/13/2023]
Abstract
In order to disentangle the physical effects at the origin of transition metal K-edge X-ray magnetic circular dichroism (XMCD) in coordination polymers and quantify small structural distortions from the intensity of these signals, a systematic investigation of Prussian blue analogs as model compounds is being conducted. Here the effects of the temperature and of the external magnetic field are tackled; none of these external parameters modify the shape of the XMCD signal but they both critically modify its intensity. The optimized experimental conditions, as well as a reliable and robust normalization procedure, could thus be determined for the study of the intrinsic parameters. Through an extended discussion on measurements on other XMCD-dedicated beamlines and for other coordination compounds, we finally provide new transition metal K-edge XMCD users with useful information to initiate and successfully carry out their projects.
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Affiliation(s)
- Adama N'Diaye
- ICMMO, Université Paris Saclay, CNRS, 15 rue Georges Clémenceau, 91405 Orsay, France
| | - Amélie Bordage
- ICMMO, Université Paris Saclay, CNRS, 15 rue Georges Clémenceau, 91405 Orsay, France
| | - Lucie Nataf
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - François Baudelet
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - Thierry Moreno
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - Anne Bleuzen
- ICMMO, Université Paris Saclay, CNRS, 15 rue Georges Clémenceau, 91405 Orsay, France
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24
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Sasabe N, Kimata M, Nakamura T. Presence of X-Ray Magnetic Circular Dichroism Signal for Zero-Magnetization Antiferromagnetic State. PHYSICAL REVIEW LETTERS 2021; 126:157402. [PMID: 33929244 DOI: 10.1103/physrevlett.126.157402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 02/12/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
X-ray magnetic circular dichroism (XMCD) is generally not observed for antiferromagnetic (AFM) states because XMCD signals from the antiparallelly coupled spins cancel each other. In this Letter, we theoretically show the presence of an XMCD signal from compensated two-dimensional triangle AFM structures on a Kagome lattice. The calculation reveals the complete correspondence between the XMCD spectra and the sign of the spin chirality: the XMCD signal only appears when the spin chirality is negative. This XMCD signal originates from the different absorption coefficients of the three sublattices reflecting different charge density anisotropies and directions of spin and orbital magnetic moments.
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Affiliation(s)
- Norimasa Sasabe
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
| | - Motoi Kimata
- Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Tetsuya Nakamura
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
- Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577, Japan
- International Center for Synchrotron Radiation Innovation Smart, Tohoku University, Sendai, Miyagi 980-8577, Japan
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25
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Mayr S, Flajšman L, Finizio S, Hrabec A, Weigand M, Förster J, Stoll H, Heyderman LJ, Urbánek M, Wintz S, Raabe J. Spin-Wave Emission from Vortex Cores under Static Magnetic Bias Fields. NANO LETTERS 2021; 21:1584-1590. [PMID: 33544597 DOI: 10.1021/acs.nanolett.0c03740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We studied the influence of a static in-plane magnetic field on the alternating-field-driven emission of nanoscale spin waves from magnetic vortex cores. Time-resolved scanning transmission X-ray microscopy was used to image spin waves in disk structures of synthetic ferrimagnets and single ferromagnetic layers. For both systems, it was found that an increasing magnetic bias field continuously displaces the wave-emitting vortex core from the center of the disk toward its edge without noticeably altering the spin-wave dispersion relation. In the case of the single-layer disk, an anisotropic lateral expansion of the core occurs at higher magnetic fields, which leads to a directional rather than radial-isotropic emission and propagation of waves. Micromagnetic simulations confirm these findings and further show that focusing effects occur in such systems, depending on the shape of the core and controlled by the static magnetic bias field.
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Affiliation(s)
- Sina Mayr
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Lukáš Flajšman
- CEITEC BUT, Brno University of Technology, 61200 Brno, Czech Republic
- NanoSpin, Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland
| | | | - Aleš Hrabec
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Magnetism and Interface Physics, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Johannes Förster
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Hermann Stoll
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Laura J Heyderman
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Michal Urbánek
- CEITEC BUT, Brno University of Technology, 61200 Brno, Czech Republic
| | - Sebastian Wintz
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Jörg Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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26
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Revealing noncollinear magnetic ordering at the atomic scale via XMCD. Sci Rep 2021; 11:2996. [PMID: 33542346 PMCID: PMC7862308 DOI: 10.1038/s41598-021-82518-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/18/2021] [Indexed: 11/08/2022] Open
Abstract
Mass-selected V and Fe monomers, as well as the heterodimer \documentclass[12pt]{minimal}
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\begin{document}$${\text{Fe}}_1{\text{V}}_1$$\end{document}Fe1V1, were deposited on a Cu(001) surface. Their electronic and magnetic properties were investigated via X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy. Anisotropies in the magnetic moments of the deposited species could be examined by means of angle resolving XMCD, i.e. changing the X-ray angle of incidence. A weak adatom-substrate-coupling was found for both elements and, using group theoretical arguments, the ground state symmetries of the adatoms were determined. For the dimer, a switching from antiparallel to parallel orientation of the respective magnetic moments was observed. We show that this is due to the existence of a noncollinear spin-flop phase in the deposited dimers, which could be observed for the first time in such a small system. Making use of the two magnetic sublattices model, we were able to find the relative orientations for the dimer magnetic moments for different incidence angles.
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27
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Schulze KS, Loetzsch R, Rüffer R, Uschmann I, Röhlsberger R, Paulus GG. X-ray dichroism in polyimide caused by non-resonant scattering. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:176-180. [PMID: 33399566 PMCID: PMC7842229 DOI: 10.1107/s1600577520015568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Dichroism is one of the most important optical effects in both the visible and the X-ray range. Besides absorption, scattering can also contribute to dichroism. This paper demonstrates that, based on the example of polyimide, materials can show tiny dichroism even far from electronic resonances due to scattering. Although the effect is small, it can lead to a measurable polarization change and might have influence on highly sensitive polarimetric experiments.
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Affiliation(s)
- K. S. Schulze
- Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany
| | - R. Loetzsch
- Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - R. Rüffer
- ESRF – The European Synchrotron, CS 40220, 38043 Grenoble Cedex 9, France
| | - I. Uschmann
- Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - R. Röhlsberger
- Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany
- Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - G. G. Paulus
- Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
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28
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Kerber N, Ksenzov D, Freimuth F, Capotondi F, Pedersoli E, Lopez-Quintas I, Seng B, Cramer J, Litzius K, Lacour D, Zabel H, Mokrousov Y, Kläui M, Gutt C. Faster chiral versus collinear magnetic order recovery after optical excitation revealed by femtosecond XUV scattering. Nat Commun 2020; 11:6304. [PMID: 33298908 PMCID: PMC7726566 DOI: 10.1038/s41467-020-19613-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 10/12/2020] [Indexed: 11/09/2022] Open
Abstract
While chiral spin structures stabilized by Dzyaloshinskii-Moriya interaction (DMI) are candidates as novel information carriers, their dynamics on the fs-ps timescale is little known. Since with the bulk Heisenberg exchange and the interfacial DMI two distinct exchange mechanisms are at play, the ultrafast dynamics of the chiral order needs to be ascertained and compared to the dynamics of the conventional collinear order. Using an XUV free-electron laser we determine the fs-ps temporal evolution of the chiral order in domain walls in a magnetic thin film sample by an IR pump - X-ray magnetic scattering probe experiment. Upon demagnetization we observe that the dichroic (CL-CR) signal connected with the chiral order correlator mzmx in the domain walls recovers significantly faster than the (CL + CR) sum signal representing the average collinear domain magnetization mz2 + mx2. We explore possible explanations based on spin structure dynamics and reduced transversal magnetization fluctuations inside the domain walls and find that the latter can explain the experimental data leading to different dynamics for collinear magnetic order and chiral magnetic order. Chiral spin structures have great promise for future information processing applications, however little is known about their ultrafast dynamics. In this experimental study, the authors use femtosecond temporal evolution to observe the fast recovery of chiral magnetic order.
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Affiliation(s)
- Nico Kerber
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany
| | - Dmitriy Ksenzov
- Department Physik, Universität Siegen, Walter-Flex-Strasse 3, 57072, Siegen, Germany
| | - Frank Freimuth
- Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany
| | | | | | | | - Boris Seng
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany.,Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506, Vandoeuvre-lès-Nancy, France
| | - Joel Cramer
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany
| | - Kai Litzius
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany
| | - Daniel Lacour
- Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506, Vandoeuvre-lès-Nancy, France
| | - Hartmut Zabel
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany.,Department of Physics, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Yuriy Mokrousov
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany.,Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany
| | - Mathias Kläui
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany. .,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany.
| | - Christian Gutt
- Department Physik, Universität Siegen, Walter-Flex-Strasse 3, 57072, Siegen, Germany.
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29
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Burns SR, Paull O, Juraszek J, Nagarajan V, Sando D. The Experimentalist's Guide to the Cycloid, or Noncollinear Antiferromagnetism in Epitaxial BiFeO 3. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003711. [PMID: 32954556 DOI: 10.1002/adma.202003711] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/30/2020] [Indexed: 06/11/2023]
Abstract
Bismuth ferrite (BiFeO3 ) is one of the most widely studied multiferroics. The coexistence of ferroelectricity and antiferromagnetism in this compound has driven an intense search for electric-field control of the magnetic order. Such efforts require a complete understanding of the various exchange interactions that underpin the magnetic behavior. An important characteristic of BiFeO3 is its noncollinear magnetic order; namely, a long-period incommensurate spin cycloid. Here, the progress in understanding this fascinating aspect of BiFeO3 is reviewed, with a focus on epitaxial films. The advances made in developing the theory used to capture the complexities of the cycloid are first chronicled, followed by a description of the various experimental techniques employed to probe the magnetic order. To help the reader fully grasp the nuances associated with thin films, a detailed description of the spin cycloid in the bulk is provided. The effects of various perturbations on the cycloid are then described: magnetic and electric fields, doping, epitaxial strain, finite size effects, and temperature. To conclude, an outlook on possible device applications exploiting noncollinear magnetism in BiFeO3 films is presented. It is hoped that this work will act as a comprehensive experimentalist's guide to the spin cycloid in BiFeO3 thin films.
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Affiliation(s)
- Stuart R Burns
- School of Materials Science and Engineering, UNSW Sydney, High Street, Kensington, Sydney, 2052, Australia
- Department of Chemistry, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Oliver Paull
- School of Materials Science and Engineering, UNSW Sydney, High Street, Kensington, Sydney, 2052, Australia
| | - Jean Juraszek
- Normandie University, UNIROUEN, INSA Rouen, CNRS, GPM, Rouen, 76000, France
| | - Valanoor Nagarajan
- School of Materials Science and Engineering, UNSW Sydney, High Street, Kensington, Sydney, 2052, Australia
| | - Daniel Sando
- School of Materials Science and Engineering, UNSW Sydney, High Street, Kensington, Sydney, 2052, Australia
- Mark Wainwright Analytical Centre, UNSW Sydney, High Street, Kensington, Sydney, 2052, Australia
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30
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Burn DM, Zhang SL, Yu GQ, Guang Y, Chen HJ, Qiu XP, van der Laan G, Hesjedal T. Depth-Resolved Magnetization Dynamics Revealed by X-Ray Reflectometry Ferromagnetic Resonance. PHYSICAL REVIEW LETTERS 2020; 125:137201. [PMID: 33034462 DOI: 10.1103/physrevlett.125.137201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Magnetic multilayers offer diverse opportunities for the development of ultrafast functional devices through advanced interface and layer engineering. Nevertheless, a method for determining their dynamic properties as a function of depth throughout such stacks has remained elusive. By probing the ferromagnetic resonance modes with element-selective soft x-ray resonant reflectivity, we gain access to the magnetization dynamics as a function of depth. Most notably, using reflectometry ferromagnetic resonance, we find a phase lag between the coupled ferromagnetic layers in [CoFeB/MgO/Ta]_{4} multilayers that is invisible to other techniques. The use of reflectometry ferromagnetic resonance enables the time-resolved and depth-resolved probing of the complex magnetization dynamics of a wide range of functional magnetic heterostructures with absorption edges in the soft x-ray wavelength regime.
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Affiliation(s)
- D M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - S L Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - G Q Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Y Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - H J Chen
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - X P Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - G van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - T Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
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31
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Poldi EHT, Escanhoela CA, Fonseca J, Eleotério MAS, Dos Reis RD, Lang JC, Haskel D, Souza-Neto NM. A versatile X-ray phase retarder for lock-in XMCD measurements. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1240-1246. [PMID: 32876599 DOI: 10.1107/s1600577520009558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
X-ray magnetic circular dichroism (XMCD) is a technique commonly used to probe magnetic properties of materials with element and orbital selectivity, which requires the use of circularly polarized (CP) X-rays. It is possible to accomplish XMCD experiments with fixed CP and alternating the magnetic field orientation, but most reliable data are obtained when alternating the magnetization orientation and the polarization between right and left helicities. A versatile strategy has been developed to perform XMCD experiments using a hard X-ray quarter-wave plate, at both polychromatic dispersive and conventional monochromatic optics, in combination with synchronous data acquisition. The switching frequency waveform is fed into a lock-in amplifier to detect and amplify the XMCD signal. The results on a reference sample demonstrate an improvement in data quality and acquisition time. The instrumentation successfully generated 98% of CP X-rays switching the beam helicity at 13 Hz, with the possibility of faster helicity switching once it is installed at the new Brazilian fourth-generation source, SIRIUS.
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Affiliation(s)
- Eduardo H T Poldi
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Carlos A Escanhoela
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Jairo Fonseca
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Marcos A S Eleotério
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Ricardo D Dos Reis
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Jonathan C Lang
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Daniel Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Narcizo M Souza-Neto
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
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32
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Serri M, Cucinotta G, Poggini L, Serrano G, Sainctavit P, Strychalska-Nowak J, Politano A, Bonaccorso F, Caneschi A, Cava RJ, Sessoli R, Ottaviano L, Klimczuk T, Pellegrini V, Mannini M. Enhancement of the Magnetic Coupling in Exfoliated CrCl 3 Crystals Observed by Low-Temperature Magnetic Force Microscopy and X-ray Magnetic Circular Dichroism. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000566. [PMID: 32390212 DOI: 10.1002/adma.202000566] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/21/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Magnetic crystals formed by 2D layers interacting by weak van der Waals forces are currently a hot research topic. When these crystals are thinned to nanometric size, they can manifest strikingly different magnetic behavior compared to the bulk form. This can be the result of, for example, quantum electronic confinement effects, the presence of defects, or pinning of the crystallographic structure in metastable phases induced by the exfoliation process. In this work, an investigation of the magnetism of micromechanically cleaved CrCl3 flakes with thickness >10 nm is performed. These flakes are characterized by superconducting quantum interference device magnetometry, surface-sensitive X-ray magnetic circular dichroism, and spatially resolved magnetic force microscopy. The results highlight an enhancement of the CrCl3 antiferromagnetic interlayer interaction that appears to be independent of the flake size when the thickness is tens of nanometers. The estimated exchange field is 9 kOe, representing an increase of ≈900% compared to the one of the bulk crystals. This effect can be attributed to the pinning of the high-temperature monoclinic structure, as recently suggested by polarized Raman spectroscopy investigations in thin (8-35 nm) CrCl3 flakes.
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Affiliation(s)
- Michele Serri
- Istituto Italiano di Tecnologia-Graphene Labs, via Morego 30, Genova, 16163, Italy
| | - Giuseppe Cucinotta
- Chemistry Department "U. Schiff" and INSTM RU, Università degli studi di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, 50019, Italy
| | - Lorenzo Poggini
- Chemistry Department "U. Schiff" and INSTM RU, Università degli studi di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, 50019, Italy
| | - Giulia Serrano
- Chemistry Department "U. Schiff" and INSTM RU, Università degli studi di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, 50019, Italy
- Department of Industrial Engineering DIEF, and INSTM RU, Università degli Studi di Firenze, Via di S. Marta 3, Firenze, 50139, Italy
| | - Philippe Sainctavit
- Institut de Mineralogie, de Physique des Materiaux et de Cosmochimie UMR 7590, CNRS, Sorbonne Université, MNHN, Paris, F-75005, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, Gif-sur-Yvette, F-91192, France
| | - Judyta Strychalska-Nowak
- Faculty of Applied Physics and Mathematics, Advanced Materials Center Gdansk University of Technology, Gdansk, 80-233, Poland
| | - Antonio Politano
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università dell'Aquila, Via Vetoio 10, L'Aquila, 67100, Italy
- CNR-IMM Istituto per la Microelettronica e Microsistemi, VIII strada 5, Catania, I-95121, Italy
| | - Francesco Bonaccorso
- Istituto Italiano di Tecnologia-Graphene Labs, via Morego 30, Genova, 16163, Italy
- BeDimensional Spa, Genoa, 16163, Italy
| | - Andrea Caneschi
- Department of Industrial Engineering DIEF, and INSTM RU, Università degli Studi di Firenze, Via di S. Marta 3, Firenze, 50139, Italy
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Roberta Sessoli
- Chemistry Department "U. Schiff" and INSTM RU, Università degli studi di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, 50019, Italy
| | - Luca Ottaviano
- Dipartimento di Scienze Fisiche e Chimiche (DSFC), Università dell'Aquila, Via Vetoio 10, L'Aquila, 67100, Italy
- CNR-SPIN UoS L'Aquila, Via Vetoio 46, L'Aquila, 67100, Italy
| | - Tomasz Klimczuk
- Faculty of Applied Physics and Mathematics, Advanced Materials Center Gdansk University of Technology, Gdansk, 80-233, Poland
| | - Vittorio Pellegrini
- Istituto Italiano di Tecnologia-Graphene Labs, via Morego 30, Genova, 16163, Italy
- BeDimensional Spa, Genoa, 16163, Italy
| | - Matteo Mannini
- Chemistry Department "U. Schiff" and INSTM RU, Università degli studi di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, 50019, Italy
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Saerbeck T, Huckfeldt H, Toperverg BP, Ehresmann A. Magnetic Structure of Ion-Beam Imprinted Stripe Domains Determined by Neutron Scattering. NANOMATERIALS 2020; 10:nano10040752. [PMID: 32326456 PMCID: PMC7221941 DOI: 10.3390/nano10040752] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/06/2020] [Accepted: 04/11/2020] [Indexed: 01/01/2023]
Abstract
We present a detailed analysis of the in-plane magnetic vector configuration in head-to-head/tail-to-tail stripe domain patterns of nominal 5 μm width. The patterns have been created by He-ion bombardment induced magnetic patterning of a CoFe/IrMn3 exchange bias thin-film system. Quantitative information about the chemical and magnetic structure is obtained from polarized neutron reflectometry (PNR) and off-specular scattering (OSS). The technique provides information on the magnetic vector orientation and magnitude along the lateral coordinate of the sample, as well as the chemical and magnetic layer structure as a function of depth. Additional sensitivity to magnetic features is obtained through a neutron wave field resonance, which is fully accounted for in the presented analysis. The scattering reveals a domain width imbalance of 5.3 to 3.7 μm of virgin and bombarded stripes, respectively. Further, we report that the magnetization in the bombarded stripe significantly deviates from the head-to-head arrangement. A domain wall of 0.6 μm with homogeneous magnetization direction is found to separate the two neighboring domains. The results contain detailed information on length scales and magnetization vectors provided by PNR and OSS in absolute units. We illustrate the complementarity of the technique to microscopy techniques for obtaining a quantitative description of imprinted magnetic domain patterns and illustrate its applicability to different sample systems.
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Affiliation(s)
- Thomas Saerbeck
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, CEDEX 9, 38042 Grenoble, France;
- Correspondence:
| | - Henning Huckfeldt
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, D-34132 Kassel, Germany; (H.H.); (A.E.)
| | - Boris P. Toperverg
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, CEDEX 9, 38042 Grenoble, France;
- Petersburg Nuclear Physics Institute, National Research Center “Kurchatov Institute”, 188300 Gatchina, Saint Petersburg, Russia
| | - Arno Ehresmann
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, D-34132 Kassel, Germany; (H.H.); (A.E.)
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34
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Creating zero-field skyrmions in exchange-biased multilayers through X-ray illumination. Nat Commun 2020; 11:949. [PMID: 32075968 PMCID: PMC7031520 DOI: 10.1038/s41467-020-14769-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 01/29/2020] [Indexed: 11/15/2022] Open
Abstract
Skyrmions, magnetic textures with topological stability, hold promises for high-density and energy-efficient information storage devices owing to their small size and low driving-current density. Precise creation of a single nanoscale skyrmion is a prerequisite to further understand the skyrmion physics and tailor skyrmion-based applications. Here, we demonstrate the creation of individual skyrmions at zero-field in an exchange-biased magnetic multilayer with exposure to soft X-rays. In particular, a single skyrmion with 100-nm size can be created at the desired position using a focused X-ray spot of sub-50-nm size. This single skyrmion creation is driven by the X-ray-induced modification of the antiferromagnetic order and the corresponding exchange bias. Furthermore, artificial skyrmion lattices with various arrangements can be patterned using X-ray. These results demonstrate the potential of accurate optical control of single skyrmion at sub-100 nm scale. We envision that X-ray could serve as a versatile tool for local manipulation of magnetic orders. Skyrmions are objects with whirled magnetization protected by their topology that can be created by different means, however, without control of their position. Here, the authors present a method exploiting x-rays to create skyrmions at the beam position allowing for creation of artificial skyrmion lattices.
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Liu Y, Luchini A, Martí-Sánchez S, Koch C, Schuwalow S, Khan SA, Stankevič T, Francoual S, Mardegan JRL, Krieger JA, Strocov VN, Stahn J, Vaz CAF, Ramakrishnan M, Staub U, Lefmann K, Aeppli G, Arbiol J, Krogstrup P. Coherent Epitaxial Semiconductor-Ferromagnetic Insulator InAs/EuS Interfaces: Band Alignment and Magnetic Structure. ACS APPLIED MATERIALS & INTERFACES 2020; 12:8780-8787. [PMID: 31877013 DOI: 10.1021/acsami.9b15034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hybrid semiconductor-ferromagnetic insulator heterostructures are interesting due to their tunable electronic transport, self-sustained stray field, and local proximitized magnetic exchange. In this work, we present lattice-matched hybrid epitaxy of semiconductor-ferromagnetic insulator InAs/EuS heterostructures and analyze the atomic-scale structure and their electronic and magnetic characteristics. The Fermi level at the InAs/EuS interface is found to be close to the InAs conduction band and in the band gap of EuS, thus preserving the semiconducting properties. Both neutron and X-ray reflectivity measurements show that the overall ferromagnetic component is mainly localized in the EuS thin film with a suppression of the Eu moment in the EuS layer nearest the InAs and magnetic moments outside the detection limits on the pure InAs side. This work presents a step toward realizing defect-free semiconductor-ferromagnetic insulator epitaxial hybrids for spin-lifted quantum and spintronic applications without external magnetic fields.
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Affiliation(s)
- Yu Liu
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | | | - Sara Martí-Sánchez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Catalonia , Spain
| | - Christian Koch
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Catalonia , Spain
| | - Sergej Schuwalow
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | - Sabbir A Khan
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | - Tomaš Stankevič
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | - Sonia Francoual
- Deutsches Elektronen-Synchrotron DESY , Hamburg 22603 , Germany
| | | | | | | | - Jochen Stahn
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | - Carlos A F Vaz
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | | | - Urs Staub
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | | | - Gabriel Aeppli
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
- ETH , CH-8093 Zürich , Switzerland
- EPFL , CH-1015 Lausanne , Switzerland
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Catalonia , Spain
- ICREA , Pg. Lluís Companys 23 , 08010 Barcelona , Catalonia , Spain
| | - Peter Krogstrup
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
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Witte K, Späth A, Finizio S, Donnelly C, Watts B, Sarafimov B, Odstrcil M, Guizar-Sicairos M, Holler M, Fink RH, Raabe J. From 2D STXM to 3D Imaging: Soft X-ray Laminography of Thin Specimens. NANO LETTERS 2020; 20:1305-1314. [PMID: 31951418 DOI: 10.1021/acs.nanolett.9b04782] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
X-ray tomography has become an indispensable tool for studying complex 3D interior structures with high spatial resolution. Three-dimensional imaging using soft X-rays offers powerful contrast mechanisms but has seen limited success with tomography due to the restrictions imposed by the much lower energy of the probe beam. The generalized geometry of laminography, characterized by a tilted axis of rotation, provides nm-scale 3D resolution for the investigation of extended (mm range) but thin (μm to nm) samples that are well suited to soft X-ray studies. This work reports on the implementation of soft X-ray laminography (SoXL) at the scanning transmission X-ray spectromicroscope of the PolLux beamline at the Swiss Light Source, Paul Scherrer Institut, which enables 3D imaging of extended specimens from 270 to 1500 eV. Soft X-ray imaging provides contrast mechanisms for both chemical sensitivity to molecular bonds and oxidation states and magnetic dichroism due to the much stronger attenuation of X-rays in this energy range. The presented examples of applications range from functionalized nanomaterials to biological photonic crystals and sophisticated nanoscaled magnetic domain patterns, thus illustrating the wide fields of research that can benefit from SoXL.
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Affiliation(s)
- Katharina Witte
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Andreas Späth
- Department Chemie und Pharmazie, Physikalische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstrasse 3 , 91058 Erlangen , Germany
| | - Simone Finizio
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Claire Donnelly
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge , CB3 0HE , United Kingdom
| | - Benjamin Watts
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Blagoj Sarafimov
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Michal Odstrcil
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Manuel Guizar-Sicairos
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Mirko Holler
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Rainer H Fink
- Department Chemie und Pharmazie, Physikalische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstrasse 3 , 91058 Erlangen , Germany
| | - Jörg Raabe
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
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Luo C, Ryll H, Back CH, Radu F. X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems. Sci Rep 2019; 9:18169. [PMID: 31796813 PMCID: PMC6890699 DOI: 10.1038/s41598-019-54356-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 11/11/2019] [Indexed: 11/09/2022] Open
Abstract
Ferrimagnetic alloys are extensively studied for their unique magnetic properties leading to possible applications in perpendicular magnetic recording, due to their deterministic ultrafast switching and heat assisted magnetic recording capabilities. On a prototype ferrimagnetic alloy we demonstrate fascinating properties that occur close to a critical temperature where the magnetization is vanishing, just as in an antiferromagnet. From the X-ray magnetic circular dichroism measurements, an anomalous 'wing shape' hysteresis loop is observed slightly above the compensation temperature. This bears the characteristics of an intrinsic exchange bias effect, referred to as atomic exchange bias. We further exploit the X-ray magnetic linear dichroism (XMLD) contrast for probing non-collinear states which allows us to discriminate between two main reversal mechanisms, namely perpendicular domain wall formation versus spin-flop transition. Ultimately, we analyze the elemental magnetic moments for the surface and the bulk parts, separately, which allows to identify in the phase diagram the temperature window where this effect takes place. Moreover, we suggests that this effect is a general phenomenon in ferrimagnetic thin films which may also contribute to the understanding of the mechanism behind the all optical switching effect.
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Affiliation(s)
- Chen Luo
- Helmholtz-Zentrum-Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489, Berlin, Germany. .,Institute of Experimental and Applied Physics, University of Regensburg, 93053, Regensburg, Germany. .,Institute of Experimental Physics of Functional Spin Systems, Technical University Munich, James-Franck-Str. 1, 85748, Garching b. München, Germany.
| | - Hanjo Ryll
- Helmholtz-Zentrum-Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Christian H Back
- Institute of Experimental and Applied Physics, University of Regensburg, 93053, Regensburg, Germany.,Institute of Experimental Physics of Functional Spin Systems, Technical University Munich, James-Franck-Str. 1, 85748, Garching b. München, Germany
| | - Florin Radu
- Helmholtz-Zentrum-Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, 12489, Berlin, Germany.
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38
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Finizio S, Zeissler K, Wintz S, Mayr S, Weßels T, Huxtable AJ, Burnell G, Marrows CH, Raabe J. Deterministic Field-Free Skyrmion Nucleation at a Nanoengineered Injector Device. NANO LETTERS 2019; 19:7246-7255. [PMID: 31525983 DOI: 10.1021/acs.nanolett.9b02840] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Magnetic skyrmions are topological solitons promising for applications as encoders for digital information. A number of different skyrmion-based memory devices have been recently proposed. In order to demonstrate a viable skyrmion-based memory device, it is necessary to reliably and reproducibly nucleate, displace, detect, and delete the magnetic skyrmions, possibly in the absence of external applied magnetic fields, which would needlessly complicate the device design. While the skyrmion displacement and detection have both been thoroughly investigated, much less attention has been dedicated to the study of the skyrmion nucleation process and its sub-nanosecond dynamics. In this study, we investigate the nucleation of magnetic skyrmions from a dedicated nanoengineered injector, demonstrating the reliable magnetic skyrmion nucleation at the remnant state. The sub-nanosecond dynamics of the skyrmion nucleation process were also investigated, allowing us to shine light on the physical processes driving the nucleation.
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Affiliation(s)
- Simone Finizio
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
| | - Katharina Zeissler
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Sebastian Wintz
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Institute of Ion Beam Physics and Materials Research , Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
| | - Sina Mayr
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zürich , 8093 Zürich , Switzerland
| | - Teresa Weßels
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - Alexandra J Huxtable
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Gavin Burnell
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Christopher H Marrows
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Jörg Raabe
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
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39
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Abstract
Local polarization of magnetic materials has become a well-known and widely used method for storing binary information. Numerous applications in our daily life such as credit cards, computer hard drives, and the popular magnetic drawing board toy, rely on this principle. In this work, we review the recent advances on the magnetic recording of inhomogeneous magnetic landscapes produced by superconducting films. We summarize the current compelling experimental evidence showing that magnetic recording can be applied for imprinting in a soft magnetic layer the flux trajectory taking place in a superconducting layer at cryogenic temperatures. This approach enables the ex situ observation at room temperature of the imprinted magnetic flux landscape obtained below the critical temperature of the superconducting state. The undeniable appeal of the proposed technique lies in its simplicity and the potential to improve the spatial resolution, possibly down to the scale of a few vortices.
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40
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Günther B, Dierolf M, Achterhold K, Pfeiffer F. Device for source position stabilization and beam parameter monitoring at inverse Compton X-ray sources. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:1546-1553. [PMID: 31490142 PMCID: PMC6730616 DOI: 10.1107/s1600577519006453] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 05/07/2019] [Indexed: 05/24/2023]
Abstract
Compact X-ray sources based on inverse Compton scattering provide brilliant and partially coherent X-rays in a laboratory environment. The cross section for inverse Compton scattering is very small, requiring high-power laser systems as well as small laser and electron beam sizes at the interaction point to generate sufficient flux. Therefore, these systems are very sensitive to distortions which change the overlap between the two beams. In order to monitor X-ray source position, size and flux in parallel to experiments, the beam-position monitor proposed here comprises a small knife edge whose image is acquired with an X-ray camera specifically designed to intercept only a very small fraction of the X-ray beam. Based on the source position drift recorded with the monitor, a closed-loop feedback stabilizes the X-ray source position by adjusting the laser beam trajectory. A decrease of long-term source position drifts by more than one order of magnitude is demonstrated with this device. Consequently, such a closed-loop feedback system which enables stabilization of source position drifts and flux of inverse Compton sources in parallel to experiments has a significant impact on the performance of these sources.
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Affiliation(s)
- Benedikt Günther
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Martin Dierolf
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Klaus Achterhold
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Franz Pfeiffer
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany
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41
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Speeding up the extended Kalman filter approach for denoising XMCD movies of fast magnetization dynamics. Ultramicroscopy 2019; 206:112810. [PMID: 31302505 DOI: 10.1016/j.ultramic.2019.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 10/26/2022]
Abstract
The Kalman filter is a well-established approach to get information on the time-dependent state of a system from noisy observations. In former times it has been used for systems with only a few degrees of freedom (typically about 10). The fast magnetization dynamics is often investigated by x-ray magnetic circular dichroism movies (XMCD movies) where the number of components of the state vector is very large (typically about 105). For such systems the Jacobian matrix which is required in the extended Kalman filter approach cannot be calculated numerically (as it is done in former papers) by use of the Landau-Lifschitz-Gilbert equation of motion in a finite time because of the many degrees of freedom of the state vector. In the present paper it is shown that the calculation of the Jacobian matrix can be much speeded up by using good analytical approximations, which are derived by a tensorial Green's function method to solve the linearized Landau-Lifschitz-Gilbert equation of motion. This makes it possible to investigate the dynamics of magnetic vortices and spin waves in circular discs of Permalloy, which are initiated by time-dependent external magnetic fields.
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42
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Kubota Y, Suzuki M, Katayama T, Yamamoto K, Tono K, Inubushi Y, Seki T, Takanashi K, Wadati H, Yabashi M. Polarization control with an X-ray phase retarder for high-time-resolution pump-probe experiments at SACLA. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:1139-1143. [PMID: 31274437 PMCID: PMC6613128 DOI: 10.1107/s1600577519006222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/02/2019] [Indexed: 06/09/2023]
Abstract
Control of the polarization of an X-ray free-electron laser (XFEL) has been performed using an X-ray phase retarder (XPR) in combination with an arrival timing diagnostic on BL3 of the SPring-8 Angstrom Compact free-electron LAser (SACLA). To combine with the timing diagnostic, a pink beam was incident on the XPR crystal and then monochromated in the vicinity of samples. A high degree of circular polarization of ∼97% was obtained experimentally at 11.567 keV, which agreed with calculations based on the dynamical theory of X-ray diffraction. This system enables pump-probe experiments to be operated using circular polarization with a time resolution of 40 fs to investigate ultrafast magnetic phenomena.
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Affiliation(s)
- Y. Kubota
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - M. Suzuki
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - T. Katayama
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - K. Yamamoto
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - K. Tono
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Y. Inubushi
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - T. Seki
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - K. Takanashi
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - H. Wadati
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - M. Yabashi
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
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43
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Schaffers T, Feggeler T, Pile S, Meckenstock R, Buchner M, Spoddig D, Ney V, Farle M, Wende H, Wintz S, Weigand M, Ohldag H, Ollefs K, Ney A. Extracting the Dynamic Magnetic Contrast in Time-Resolved X-ray Transmission Microscopy. NANOMATERIALS 2019; 9:nano9070940. [PMID: 31261780 PMCID: PMC6669469 DOI: 10.3390/nano9070940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 06/18/2019] [Accepted: 06/24/2019] [Indexed: 11/16/2022]
Abstract
Using a time-resolved detection scheme in scanning transmission X-ray microscopy (STXM), we measured element resolved ferromagnetic resonance (FMR) at microwave frequencies up to 10 GHz and a spatial resolution down to 20 nm at two different synchrotrons. We present different methods to separate the contribution of the background from the dynamic magnetic contrast based on the X-ray magnetic circular dichroism (XMCD) effect. The relative phase between the GHz microwave excitation and the X-ray pulses generated by the synchrotron, as well as the opening angle of the precession at FMR can be quantified. A detailed analysis for homogeneous and inhomogeneous magnetic excitations demonstrates that the dynamic contrast indeed behaves as the usual XMCD effect. The dynamic magnetic contrast in time-resolved STXM has the potential be a powerful tool to study the linear and nonlinear, magnetic excitations in magnetic micro- and nano-structures with unique spatial-temporal resolution in combination with element selectivity.
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Affiliation(s)
- Taddäus Schaffers
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria.
| | - Thomas Feggeler
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Santa Pile
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Ralf Meckenstock
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Martin Buchner
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Detlef Spoddig
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Verena Ney
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Michael Farle
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Heiko Wende
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Sebastian Wintz
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Markus Weigand
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - Hendrik Ohldag
- Stanford Synchrotron Radiation Laboratory, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Katharina Ollefs
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Andreas Ney
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria.
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44
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Werellapatha K, Escanhoela CA, Fabbris G, Haskel D, Ankudinov A, Chow P. Evolution of electronic and magnetic properties of nominal magnetite nanoparticles at high pressure probed by x-ray absorption and emission techniques. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:255301. [PMID: 30889564 DOI: 10.1088/1361-648x/ab111d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a study of electronic and magnetic properties of nominal magnetite nanoparticles (NPs) (~6 nm) at high pressure in the presence of silicon pressure medium using x-ray absorption near edge structure (XANES), x-ray magnetic circular dichroism (XMCD) and non-resonant x-ray emission spectroscopy (XES). XANES data show a reduction of Fe charge state, a change in local environment around Fe at tetrahedral sites, and a reduced occupation of Fe 4p orbitals, not seen in previous pressure studies of bulk magnetite. XMCD data show a continuous magnetic moment reduction of ~50% between ambient pressure and 20 GPa, similar to what was observed in previous bulk magnetite studies. XES spectra of NPs indicate a gradual change in spin configuration away from the high-spin state consistent with a postulated charge transfer from Fe 4p to 3d states and the observed reduction in XMCD signal. Taken together, the results point to substantial differences in the response of electronic and magnetic properties of the nano-counterparts of bulk magnetite at high pressure.
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Affiliation(s)
- Kalpani Werellapatha
- Department of Physics and Astronomy, University of Maine, Orono, ME 04469, United States of America
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45
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Sluka V, Schneider T, Gallardo RA, Kákay A, Weigand M, Warnatz T, Mattheis R, Roldán-Molina A, Landeros P, Tiberkevich V, Slavin A, Schütz G, Erbe A, Deac A, Lindner J, Raabe J, Fassbender J, Wintz S. Emission and propagation of 1D and 2D spin waves with nanoscale wavelengths in anisotropic spin textures. NATURE NANOTECHNOLOGY 2019; 14:328-333. [PMID: 30804478 DOI: 10.1038/s41565-019-0383-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/21/2019] [Indexed: 05/26/2023]
Abstract
Spin waves offer intriguing perspectives for computing and signal processing, because their damping can be lower than the ohmic losses in conventional complementary metal-oxide-semiconductor (CMOS) circuits. Magnetic domain walls show considerable potential as magnonic waveguides for on-chip control of the spatial extent and propagation of spin waves. However, low-loss guidance of spin waves with nanoscale wavelengths and around angled tracks remains to be shown. Here, we demonstrate spin wave control using natural anisotropic features of magnetic order in an interlayer exchange-coupled ferromagnetic bilayer. We employ scanning transmission X-ray microscopy to image the generation of spin waves and their propagation across distances exceeding multiples of the wavelength. Spin waves propagate in extended planar geometries as well as along straight or curved one-dimensional domain walls. We observe wavelengths between 1 μm and 150 nm, with excitation frequencies ranging from 250 MHz to 3 GHz. Our results show routes towards the practical implementation of magnonic waveguides in the form of domain walls in future spin wave logic and computational circuits.
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Affiliation(s)
- Volker Sluka
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
| | | | - Rodolfo A Gallardo
- Universidad Técnica Federico Santa María, Valparaíso, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
| | - Attila Kákay
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Markus Weigand
- Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany
| | - Tobias Warnatz
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Uppsala Universitet, Uppsala, Sweden
| | - Roland Mattheis
- Leibniz Institut für Photonische Technologien, Jena, Germany
| | | | - Pedro Landeros
- Universidad Técnica Federico Santa María, Valparaíso, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
| | | | | | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany
| | - Artur Erbe
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Alina Deac
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | | | - Jörg Raabe
- Paul Scherrer Institut, Villigen, PSI, Switzerland
| | - Jürgen Fassbender
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Technische Universität Dresden, Dresden, Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
- Paul Scherrer Institut, Villigen, PSI, Switzerland.
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46
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Dieterle G, Förster J, Stoll H, Semisalova AS, Finizio S, Gangwar A, Weigand M, Noske M, Fähnle M, Bykova I, Gräfe J, Bozhko DA, Musiienko-Shmarova HY, Tiberkevich V, Slavin AN, Back CH, Raabe J, Schütz G, Wintz S. Coherent Excitation of Heterosymmetric Spin Waves with Ultrashort Wavelengths. PHYSICAL REVIEW LETTERS 2019; 122:117202. [PMID: 30951356 DOI: 10.1103/physrevlett.122.117202] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 06/09/2023]
Abstract
In the emerging field of magnonics, spin waves are foreseen as signal carriers for future spintronic information processing and communication devices, owing to both the very low power losses and a high device miniaturization potential predicted for short-wavelength spin waves. Yet, the efficient excitation and controlled propagation of nanoscale spin waves remains a severe challenge. Here, we report the observation of high-amplitude, ultrashort dipole-exchange spin waves (down to 80 nm wavelength at 10 GHz frequency) in a ferromagnetic single layer system, coherently excited by the driven dynamics of a spin vortex core. We used time-resolved x-ray microscopy to directly image such propagating spin waves and their excitation over a wide range of frequencies. By further analysis, we found that these waves exhibit a heterosymmetric mode profile, involving regions with anti-Larmor precession sense and purely linear magnetic oscillation. In particular, this mode profile consists of dynamic vortices with laterally alternating helicity, leading to a partial magnetic flux closure over the film thickness, which is explained by a strong and unexpected mode hybridization. This spin-wave phenomenon observed is a general effect inherent to the dynamics of sufficiently thick ferromagnetic single layer films, independent of the specific excitation method employed.
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Affiliation(s)
- G Dieterle
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - J Förster
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - H Stoll
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
- Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - A S Semisalova
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - S Finizio
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - A Gangwar
- Universität Regensburg, 93053 Regensburg, Germany
| | - M Weigand
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - M Noske
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - M Fähnle
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - I Bykova
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - J Gräfe
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - D A Bozhko
- Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | | | | | - A N Slavin
- Oakland University, Rochester, Michigan 48309, USA
| | - C H Back
- Universität Regensburg, 93053 Regensburg, Germany
| | - J Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - G Schütz
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - S Wintz
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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47
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Guo EJ, Desautels R, Keavney D, Roldan MA, Kirby BJ, Lee D, Liao Z, Charlton T, Herklotz A, Zac Ward T, Fitzsimmons MR, Lee HN. Nanoscale ferroelastic twins formed in strained LaCoO 3 films. SCIENCE ADVANCES 2019; 5:eaav5050. [PMID: 30944859 PMCID: PMC6440751 DOI: 10.1126/sciadv.aav5050] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 02/06/2019] [Indexed: 05/25/2023]
Abstract
The coexistence and coupling of ferroelasticity and magnetic ordering in a single material offers a great opportunity to realize novel devices with multiple tuning knobs. Complex oxides are a particularly promising class of materials to find multiferroic interactions due to their rich phase diagrams, and are sensitive to external perturbations. Still, there are very few examples of these systems. Here, we report the observation of twin domains in ferroelastic LaCoO3 epitaxial films and their geometric control of structural symmetry intimately linked to the material's electronic and magnetic states. A unidirectional structural modulation is achieved by selective choice of substrates having twofold rotational symmetry. This modulation perturbs the crystal field-splitting energy, leading to unexpected in-plane anisotropy of orbital configuration and magnetization. These findings demonstrate the use of structural modulation to control multiferroic interactions and may enable a great potential for stimulation of exotic phenomena through artificial domain engineering.
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Affiliation(s)
- Er-Jia Guo
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - David Keavney
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Manuel A. Roldan
- Eyring Materials Center, Arizona State University, Tempe, AZ 85287, USA
| | - Brian J. Kirby
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Dongkyu Lee
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | | | - Andreas Herklotz
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Institute for Physics, Martin-Luther-University Halle-Wittenberg, Halle (Saale) 06120, Germany
| | - T. Zac Ward
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Michael R. Fitzsimmons
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
| | - Ho Nyung Lee
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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48
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Finizio S, Wintz S, Zeissler K, Sadovnikov AV, Mayr S, Nikitov SA, Marrows CH, Raabe J. Dynamic Imaging of the Delay- and Tilt-Free Motion of Néel Domain Walls in Perpendicularly Magnetized Superlattices. NANO LETTERS 2019; 19:375-380. [PMID: 30517003 DOI: 10.1021/acs.nanolett.8b04091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report on the time-resolved investigation of current- and field-induced domain wall motion in the flow regime in perpendicularly magnetized microwires exhibiting antisymmetric exchange interaction by means of scanning transmission X-ray microscopy with a 200 ps time step. The sub-ns time step of the dynamical images allowed us to observe the absence of incubation times for the motion of the domain wall within an uncertainty of 200 ps, together with indications for a negligible inertia of the domain wall. Furthermore, we observed that, for short current and magnetic field pulses, the magnetic domain walls do not exhibit a tilting during their motion, providing a mechanism for the fast, tilt-free, current-induced motion of magnetic domain walls.
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Affiliation(s)
- Simone Finizio
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
| | - Sebastian Wintz
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
| | - Katharina Zeissler
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Alexandr V Sadovnikov
- Laboratory Metamaterials , Saratov State University , Saratov 410012 , Russia
- Kotel'nikov Institute of Radioengineering and Electronics , Russian Academy of Sciences , Moscow 125009 , Russia
| | - Sina Mayr
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Department of Materials, Laboratory for Mesoscopic Systems , ETH Zürich , 8093 Zürich , Switzerland
| | - Sergey A Nikitov
- Laboratory Metamaterials , Saratov State University , Saratov 410012 , Russia
- Kotel'nikov Institute of Radioengineering and Electronics , Russian Academy of Sciences , Moscow 125009 , Russia
| | - Christopher H Marrows
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Jörg Raabe
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
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49
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Gaul A, Emmrich D, Ueltzhöffer T, Huckfeldt H, Doğanay H, Hackl J, Khan MI, Gottlob DM, Hartmann G, Beyer A, Holzinger D, Nemšák S, Schneider CM, Gölzhäuser A, Reiss G, Ehresmann A. Size limits of magnetic-domain engineering in continuous in-plane exchange-bias prototype films. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:2968-2979. [PMID: 30591845 PMCID: PMC6296425 DOI: 10.3762/bjnano.9.276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Background: The application of superparamagnetic particles as biomolecular transporters in microfluidic systems for lab-on-a-chip applications crucially depends on the ability to control their motion. One approach for magnetic-particle motion control is the superposition of static magnetic stray field landscapes (MFLs) with dynamically varying external fields. These MFLs may emerge from magnetic domains engineered both in shape and in their local anisotropies. Motion control of smaller beads does necessarily need smaller magnetic patterns, i.e., MFLs varying on smaller lateral scales. The achievable size limit of engineered magnetic domains depends on the magnetic patterning method and on the magnetic anisotropies of the material system. Smallest patterns are expected to be in the range of the domain wall width of the particular material system. To explore these limits a patterning technology is needed with a spatial resolution significantly smaller than the domain wall width. Results: We demonstrate the application of a helium ion microscope with a beam diameter of 8 nm as a mask-less method for local domain patterning of magnetic thin-film systems. For a prototypical in-plane exchange-bias system the domain wall width has been investigated as a function of the angle between unidirectional anisotropy and domain wall. By shrinking the domain size of periodic domain stripes, we analyzed the influence of domain wall overlap on the domain stability. Finally, by changing the geometry of artificial two-dimensional domains, the influence of domain wall overlap and domain wall geometry on the ultimate domain size in the chosen system was analyzed. Conclusion: The application of a helium ion microscope for magnetic patterning has been shown. It allowed for exploring the fundamental limits of domain engineering in an in-plane exchange-bias thin film as a prototypical system. For two-dimensional domains the limit depends on the domain geometry. The relative orientation between domain wall and anisotropy axes is a crucial parameter and therefore influences the achievable minimum domain size dramatically.
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Affiliation(s)
- Alexander Gaul
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, 34132 Kassel, Germany
| | - Daniel Emmrich
- Faculty of Physics, Physics of supramolecular Systems and Surfaces, University of Bielefeld, 33501 Bielefeld, Germany
| | - Timo Ueltzhöffer
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, 34132 Kassel, Germany
- PT-DESY, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Henning Huckfeldt
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, 34132 Kassel, Germany
| | - Hatice Doğanay
- Peter Grünberg Institute “Electronic Properties”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Johanna Hackl
- Peter Grünberg Institute “Electronic Properties”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Muhammad Imtiaz Khan
- Peter Grünberg Institute “Electronic Properties”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Daniel M Gottlob
- Peter Grünberg Institute “Electronic Properties”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Gregor Hartmann
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, 34132 Kassel, Germany
| | - André Beyer
- Faculty of Physics, Physics of supramolecular Systems and Surfaces, University of Bielefeld, 33501 Bielefeld, Germany
| | - Dennis Holzinger
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, 34132 Kassel, Germany
| | - Slavomír Nemšák
- Peter Grünberg Institute “Electronic Properties”, Forschungszentrum Jülich, 52425 Jülich, Germany
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Claus M Schneider
- Peter Grünberg Institute “Electronic Properties”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Armin Gölzhäuser
- Faculty of Physics, Physics of supramolecular Systems and Surfaces, University of Bielefeld, 33501 Bielefeld, Germany
| | - Günter Reiss
- Faculty of Physics, Thin Films and Physics of Nanostructures, University of Bielefeld, 33501 Bielefeld, Germany
| | - Arno Ehresmann
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, 34132 Kassel, Germany
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50
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Kotani Y, Senba Y, Toyoki K, Billington D, Okazaki H, Yasui A, Ueno W, Ohashi H, Hirosawa S, Shiratsuchi Y, Nakamura T. Realization of a scanning soft X-ray microscope for magnetic imaging under high magnetic fields. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:1444-1449. [PMID: 30179184 PMCID: PMC6140398 DOI: 10.1107/s1600577518009177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/24/2018] [Indexed: 06/08/2023]
Abstract
For the purpose of imaging element- and shell-specific magnetic distributions under high magnetic fields, a scanning soft X-ray microscope has been developed at beamline BL25SU, SPring-8, Japan. The scanning X-ray microscope utilizes total electron yield detection of absorbed circularly polarized soft X-rays in order to observe magnetic domains through the X-ray magnetic circular dichroism effect. Crucially, this system is equipped with an 8 T superconducting magnet. The performance and features of the present system are demonstrated by magnetic domain observations of the fractured surface of a Nd14.0Fe79.7Cu0.1B6.2 sintered magnet.
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Affiliation(s)
- Yoshinori Kotani
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
| | - Yasunori Senba
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
| | - Kentaro Toyoki
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
- Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba 305-0047, Japan
| | - David Billington
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
- Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba 305-0047, Japan
| | - Hiroyuki Okazaki
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
- Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba 305-0047, Japan
| | - Akira Yasui
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
| | - Wakana Ueno
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
| | - Haruhiko Ohashi
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
| | - Satoshi Hirosawa
- Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba 305-0047, Japan
| | - Yu Shiratsuchi
- Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan
| | - Tetsuya Nakamura
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo 679-5198, Japan
- Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba 305-0047, Japan
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