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Günther S, Kratky T, Kraus J, Leidinger P, Zeller P, Sala A, Genuzio F, Jugovac M, Menteş TO, Locatelli A. Versatile procedure for the correction of non-isochromatism in XPEEM spectroscopic imaging. Ultramicroscopy 2023; 250:113756. [PMID: 37182363 DOI: 10.1016/j.ultramic.2023.113756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/16/2023] [Accepted: 05/08/2023] [Indexed: 05/16/2023]
Abstract
Non-isochromatism in X-ray PhotoEmission Electron Microscopy (XPEEM) may result in unwanted artifacts especially when working with large field of views. The lack of isochromatism of XPEEM images may result from multiple factors, for instance the energy dispersion of the X-rays on the sample or the effect of one or more dispersive elements in the electron optics of the microscope, or the combination of both. In practice, the photon energy or the electron kinetic energy may vary across the image, complicating image interpretation and analysis. The effect becomes severe when imaging at low magnification upon irradiation with high energy photons. Such imaging demands for a large X-ray illuminating spot size usually achieved by opening the exit slit of the X-ray monochromator while reducing the monochromaticity of the irradiating light. However, we show that the effect is linear and can be fully removed. A versatile correction procedure is presented which leads to true monochromatic photoelectron images at improved signal-to-noise ratio. XPEEM data recorded at the nanospectroscopy beamline of the Elettra synchrotron radiation facility illustrate the working principle of the procedure. Also, reciprocal space XPEEM data such as angle-resolved photoelectron spectroscopy (ARPES) momentum plots suffer from linear energy dispersion artifacts which can be corrected in a similar way. Representative data acquired from graphene synthesized on copper by chemical vapor deposition prove the benefits of the correction procedure.
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Affiliation(s)
- Sebastian Günther
- Chemistry Department, Physical Chemistry with Focus on Catalysis, Technical University of Munich (TUM), Lichtenbergstr 4, Garching D-85748, Germany.
| | - Tim Kratky
- Chemistry Department, Physical Chemistry with Focus on Catalysis, Technical University of Munich (TUM), Lichtenbergstr 4, Garching D-85748, Germany
| | - Jürgen Kraus
- Chemistry Department, Physical Chemistry with Focus on Catalysis, Technical University of Munich (TUM), Lichtenbergstr 4, Garching D-85748, Germany
| | - Paul Leidinger
- Chemistry Department, Physical Chemistry with Focus on Catalysis, Technical University of Munich (TUM), Lichtenbergstr 4, Garching D-85748, Germany
| | - Patrick Zeller
- Chemistry Department, Physical Chemistry with Focus on Catalysis, Technical University of Munich (TUM), Lichtenbergstr 4, Garching D-85748, Germany
| | - Alessandro Sala
- Elettra-Sincrotrone Trieste S.C.P.A., S.S. 14 - km 163,5 in Area Science Park, Basovizza, Trieste 34149, Italy
| | - Francesca Genuzio
- Elettra-Sincrotrone Trieste S.C.P.A., S.S. 14 - km 163,5 in Area Science Park, Basovizza, Trieste 34149, Italy
| | - Matteo Jugovac
- Elettra-Sincrotrone Trieste S.C.P.A., S.S. 14 - km 163,5 in Area Science Park, Basovizza, Trieste 34149, Italy
| | - Tevfik Onur Menteş
- Elettra-Sincrotrone Trieste S.C.P.A., S.S. 14 - km 163,5 in Area Science Park, Basovizza, Trieste 34149, Italy
| | - Andrea Locatelli
- Elettra-Sincrotrone Trieste S.C.P.A., S.S. 14 - km 163,5 in Area Science Park, Basovizza, Trieste 34149, Italy
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Genuzio F, Giela T, Lucian M, Menteş TO, Brondin CA, Cautero G, Mazalski P, Bonetti S, Korecki J, Locatelli A. A UHV MOKE magnetometer complementing XMCD-PEEM at the Elettra Synchrotron. J Synchrotron Radiat 2021; 28:995-1005. [PMID: 33950008 PMCID: PMC8127370 DOI: 10.1107/s1600577521002885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
We report on a custom-built UHV-compatible Magneto-Optical Kerr Effect (MOKE) magnetometer for applications in surface and materials sciences, operating in tandem with the PhotoEmission Electron Microscope (PEEM) endstation at the Nanospectroscopy beamline of the Elettra synchrotron. The magnetometer features a liquid-nitrogen-cooled electromagnet that is fully compatible with UHV operation and produces magnetic fields up to about 140 mT at the sample. Longitudinal and polar MOKE measurement geometries are realized. The magneto-optical detection is based on polarization analysis using a photoelastic modulator. The sample manipulation system is fully compatible with that of the PEEM, making it possible to exchange samples with the beamline endstation, where complementary X-ray imaging and spectroscopy techniques are available. The magnetometer performance is illustrated by experiments on cobalt ultra-thin films, demonstrating close to monolayer sensitivity. The advantages of combining in situ growth, X-ray Magnetic Circular Dichroism imaging (XMCD-PEEM) and MOKE magnetometry into a versatile multitechnique facility are highlighted.
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Affiliation(s)
| | - Tomasz Giela
- CERIC-ERIC, Basovizza, Trieste, Italy
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Kraków, Poland
| | - Matteo Lucian
- Elettra–Sincrotrone Trieste SCpA, Basovizza, Trieste, Italy
| | | | - Carlo Alberto Brondin
- Department of Molecular Sciences and Nanosytems, Ca’ Foscari University of Venice, Venezia, Italy
| | | | - Piotr Mazalski
- Faculty of Physics, University of Białystok, Białystok, Poland
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland
| | - Stefano Bonetti
- Department of Molecular Sciences and Nanosytems, Ca’ Foscari University of Venice, Venezia, Italy
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - Jozef Korecki
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland
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Zakharov AA, Mårsell E, Hilner E, Timm R, Andersen JN, Lundgren E, Mikkelsen A. Manipulating the dynamics of self-propelled gallium droplets by gold nanoparticles and nanoscale surface morphology. ACS Nano 2015; 9:5422-5431. [PMID: 25880600 DOI: 10.1021/acsnano.5b01228] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using in situ surface-sensitive electron microscopy performed in real time, we show that the dynamics of micron-sized Ga droplets on GaP(111) can be manipulated locally using Au nanoparticles. Detailed measurements of structure and dynamics of the surface from microns to atomic scale are done using both surface electron and scanning probe microscopies. Imaging is done simultaneously on areas with and without Au particles and on samples spanning an order of magnitude in particle coverages. Based on this, we establish the equations of motion that can generally describe the Ga droplet dynamics, taking into account three general features: the affinity of Ga droplets to cover steps and rough structures on the surface, the evaporation-driven transition of the surface nanoscale morphology from rough to flat, and the enhanced evaporation due to Ga droplets and Au nanoparticles. Separately, these features can induce either self-propelled random motion or directional motion, but in combination, the self-propelled motion acts to increase the directional motion even if the directional force is 100 times weaker than the random force. We then find that the Au particles initiate a faster native oxide desorption and speed up the rough to flat surface transition in their vicinity. This changes the balance of forces on the Ga droplets near the Au particles, effectively deflecting the droplets from these areas. The model is experimentally verified for the present materials system, but due to its very general assumptions, it could also be relevant for the many other materials systems that display self-propelled random motion.
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Affiliation(s)
- Alexei A Zakharov
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Erik Mårsell
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Emelie Hilner
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Rainer Timm
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Jesper N Andersen
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Edvin Lundgren
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Anders Mikkelsen
- †Department of Physics and the Nanometer Structure Consortium (nmC@LU) and ‡MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
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