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Soltan S, Macke S, Ilse SE, Pennycook T, Zhang ZL, Christiani G, Benckiser E, Schütz G, Goering E. Ferromagnetic order controlled by the magnetic interface of LaNiO 3/La 2/3Ca 1/3MnO 3 superlattices. Sci Rep 2023; 13:3847. [PMID: 36890187 PMCID: PMC9995495 DOI: 10.1038/s41598-023-30814-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/01/2023] [Indexed: 03/10/2023] Open
Abstract
Interface engineering in complex oxide superlattices is a growing field, enabling manipulation of the exceptional properties of these materials, and also providing access to new phases and emergent physical phenomena. Here we demonstrate how interfacial interactions can induce a complex charge and spin structure in a bulk paramagnetic material. We investigate a superlattice (SLs) consisting of paramagnetic LaNiO3 (LNO) and highly spin-polarized ferromagnetic La2/3Ca1/3MnO3 (LCMO), grown on SrTiO3 (001) substrate. We observed emerging magnetism in LNO through an exchange bias mechanism at the interfaces in X-ray resonant magnetic reflectivity. We find non-symmetric interface induced magnetization profiles in LNO and LCMO which we relate to a periodic complex charge and spin superstructure. High resolution scanning transmission electron microscopy images reveal that the upper and lower interfaces exhibit no significant structural variations. The different long range magnetic order emerging in LNO layers demonstrates the enormous potential of interfacial reconstruction as a tool for tailored electronic properties.
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Affiliation(s)
- S Soltan
- Physics Department, Faculty of Science, Helwan University, Helwan, Cairo, 11798, Egypt. .,Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany. .,Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
| | - S Macke
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - S E Ilse
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - T Pennycook
- EMAT, University of Antwerp Campus Groenenborger, 2020, Antwerp, Belgium.,Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Z L Zhang
- Erich-Schmid-Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, 8700, Leoben, Austria
| | - G Christiani
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - E Benckiser
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany.
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2
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Birch MT, Powalla L, Wintz S, Hovorka O, Litzius K, Loudon JC, Turnbull LA, Nehruji V, Son K, Bubeck C, Rauch TG, Weigand M, Goering E, Burghard M, Schütz G. History-dependent domain and skyrmion formation in 2D van der Waals magnet Fe 3GeTe 2. Nat Commun 2022; 13:3035. [PMID: 35641499 PMCID: PMC9156682 DOI: 10.1038/s41467-022-30740-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
The discovery of two-dimensional magnets has initiated a new field of research, exploring both fundamental low-dimensional magnetism, and prospective spintronic applications. Recently, observations of magnetic skyrmions in the 2D ferromagnet Fe3GeTe2 (FGT) have been reported, introducing further application possibilities. However, controlling the exhibited magnetic state requires systematic knowledge of the history-dependence of the spin textures, which remains largely unexplored in 2D magnets. In this work, we utilise real-space imaging, and complementary simulations, to determine and explain the thickness-dependent magnetic phase diagrams of an exfoliated FGT flake, revealing a complex, history-dependent emergence of the uniformly magnetised, stripe domain and skyrmion states. The results show that the interplay of the dominant dipolar interaction and strongly temperature dependent out-of-plane anisotropy energy terms enables the selective stabilisation of all three states at zero field, and at a single temperature, while the Dzyaloshinksii-Moriya interaction must be present to realise the observed Néel-type domain walls. The findings open perspectives for 2D devices incorporating topological spin textures. Fe3GeTe2, known as FGT, is a van der Waals magnetic material that was recently shown to host magnetic skyrmions. Here, Birch et al using both X-ray and electron microscopy to study the stability of skyrmions in FGT, revealing how the sample history can influence skyrmion formation
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Affiliation(s)
- M T Birch
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - L Powalla
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany.
| | - S Wintz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - O Hovorka
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - K Litzius
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - J C Loudon
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - L A Turnbull
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - V Nehruji
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - K Son
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.,Department of Physics Education, Kongju National University, Gongju, 32588, South Korea
| | - C Bubeck
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - T G Rauch
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, 12489, Berlin, Germany
| | - M Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, 12489, Berlin, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - M Burghard
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
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Audehm P, Schmidt M, Brück S, Tietze T, Gräfe J, Macke S, Schütz G, Goering E. Pinned orbital moments - A new contribution to magnetic anisotropy. Sci Rep 2016; 6:25517. [PMID: 27151436 PMCID: PMC4858686 DOI: 10.1038/srep25517] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/15/2016] [Indexed: 11/19/2022] Open
Abstract
Reduced dimensionality and symmetry breaking at interfaces lead to unusual local magnetic configurations, such as glassy behavior, frustration or increased anisotropy. The interface between a ferromagnet and an antiferromagnet is such an example for enhanced symmetry breaking. Here we present detailed X-ray magnetic circular dichroism and X-ray resonant magnetic reflectometry investigations on the spectroscopic nature of uncompensated pinned magnetic moments in the antiferromagnetic layer of a typical exchange bias system. Unexpectedly, the pinned moments exhibit nearly pure orbital moment character. This strong orbital pinning mechanism has not been observed so far and is not discussed in literature regarding any theory for local magnetocrystalline anisotropy energies in magnetic systems. To verify this new phenomenon we investigated the effect at different temperatures. We provide a simple model discussing the observed pure orbital moments, based on rotatable spin magnetic moments and pinned orbital moments on the same atom. This unexpected observation leads to a concept for a new type of anisotropy energy.
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Affiliation(s)
- P Audehm
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - M Schmidt
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - S Brück
- Physikalisches Institut, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - T Tietze
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - J Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - S Macke
- Quantum Matter Institute and Department of Physics and Astronomy University of British Columbia 2355 East Mall, Vancouver, V6T 1Z4, Canada.,Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
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Abstract
Measuring the magnetic configuration at complex buried layers and interfaces is an important task, which requires especially a non-destructive probing technique. X-ray resonant magnetic reflectometry (XRMR) combines the non-destructive depth profiling potential of x-ray reflectometry with the excellent sensitivity for magnetic phenomena, utilizing the x-ray magnetic circular dichroism effect. It provides the magnetic spatial distribution with a precision down to the angstrom scale, combined with element and symmetry specificity, sub-monolayer sensitivity, and the possible separation of spin and orbital magnetic moments. This review provides an overview to the XRMR technique in a tutorial way. We focus on the introduction to the theory, measurement types, and data simulation. We provide related experimental examples and show selected applications.
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Affiliation(s)
- S Macke
- Quantum Matter Institute, University of British Columbia, 2355 East Mall, Vancouver V6T 1Z4, Canada. Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
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Wohlhüter P, Rhensius J, Vaz CAF, Heidler J, Körner HS, Bisig A, Foerster M, Méchin L, Gaucher F, Locatelli A, Niño MA, El Moussaoui S, Nolting F, Goering E, Heyderman LJ, Kläui M. The effect of magnetic anisotropy on the spin configurations of patterned La(0.7)Sr(0.3)MnO3 elements. J Phys Condens Matter 2013; 25:176004. [PMID: 23567900 DOI: 10.1088/0953-8984/25/17/176004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We study the effect of magnetocrystalline anisotropy on the magnetic configurations of La0.7Sr0.3MnO3 bar and triangle elements using photoemission electron microscopy imaging. The dominant remanent state is a low energy flux-closure state for both thin (15 nm) and thick (50 nm) elements. The magnetocrystalline anisotropy, which competes with the dipolar energy, causes a strong modification of the spin configuration in the thin elements, depending on the shape, size and orientation of the structures. We investigate the magnetic switching processes and observe in triangular shaped elements a displacement of the vortex core along the easy axis for an external magnetic field applied close to the hard axis, which is well reproduced by micromagnetic simulations.
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Affiliation(s)
- P Wohlhüter
- Fachbereich Physik, Universität Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
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Satapathy DK, Uribe-Laverde MA, Marozau I, Malik VK, Das S, Wagner T, Marcelot C, Stahn J, Brück S, Rühm A, Macke S, Tietze T, Goering E, Frañó A, Kim JH, Wu M, Benckiser E, Keimer B, Devishvili A, Toperverg BP, Merz M, Nagel P, Schuppler S, Bernhard C. Magnetic proximity effect in YBa2Cu3O7/La(2/3)Ca(1/3)MnO3 and YBa2Cu3O7/LaMnO(3+δ) superlattices. Phys Rev Lett 2012; 108:197201. [PMID: 23003079 DOI: 10.1103/physrevlett.108.197201] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Indexed: 06/01/2023]
Abstract
Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa2Cu3O7 and ferromagnetic-metallic La0.67Ca0.33MnO3 or ferromagnetic-insulating LaMnO(3+δ). We find that the MPE strongly depends on the electronic state of the manganite layers, being pronounced for the ferromagnetic-metallic La0.67Ca0.33MnO3 and almost absent for ferromagnetic-insulating LaMnO(3+δ). We also detail the change of the magnetic depth profile due to the MPE and provide evidence for its intrinsic nature.
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Affiliation(s)
- D K Satapathy
- University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Chemin du Musée 3, CH-1700 Fribourg, Switzerland
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Nolle D, Weigand M, Audehm P, Goering E, Wiesemann U, Wolter C, Nolle E, Schütz G. Note: unique characterization possibilities in the ultra high vacuum scanning transmission x-ray microscope (UHV-STXM) "MAXYMUS" using a rotatable permanent magnetic field up to 0.22 T. Rev Sci Instrum 2012; 83:046112. [PMID: 22559598 DOI: 10.1063/1.4707747] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Using the x-ray magnetic circular dichroism effect, the soft x-ray range provides powerful detection capabilities concerning element specific structural, chemical, and magnetic properties. We present the implementation of a variable 0.22 T magnet system based on permanent magnets into the new UHV scanning microscope "MAXYMUS" at HZB/BESSY II, allowing surface sensitive and simultaneous standard transmission microscopic investigations in a variable external magnetic field. The outstanding potential of these new investigation possibilities will be demonstrated showing the development of the magnetic domain structure concurrently at the surface and in the bulk, providing a profound understanding of fundamental mechanisms in coupled magnetic systems.
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Affiliation(s)
- D Nolle
- Max Planck Institute for Intelligent Systems (former Metals Research), Heisenbergstr. 3, 70569 Stuttgart, Germany.
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8
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Affiliation(s)
- E. Goering
- a Institut für Physik, University of Augsburg , 86159, Augsburg , Germany
| | - O. Müller
- a Institut für Physik, University of Augsburg , 86159, Augsburg , Germany
| | - M. Klemm
- a Institut für Physik, University of Augsburg , 86159, Augsburg , Germany
| | - M. L. denBoer
- b Hunter College, City University of New York, Physics Department , New York , 10021 , USA
| | - S. Horn
- a Institut für Physik, University of Augsburg , 86159, Augsburg , Germany
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9
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Goering E, Lafkioti M, Gold S. Comment on "spin and orbital magnetic moments of Fe3O4". Phys Rev Lett 2006; 96:039701; discussion 039702. [PMID: 16486788 DOI: 10.1103/physrevlett.96.039701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Indexed: 05/06/2023]
Affiliation(s)
- E Goering
- Max-Planck-Institute for Metal Research Heisenbergstrasse 3 70569 Stuttgart, Germany
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10
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Fähnle M, Albrecht J, Eimüller T, Fischer P, Goering E, Steiauf D, Schütz G. On the imaging of the flux-line lattice of a type-II superconductor by soft X-ray absorption microscopy. J Synchrotron Radiat 2005; 12:251-253. [PMID: 15728979 DOI: 10.1107/s0909049504028936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 11/08/2004] [Indexed: 05/24/2023]
Abstract
A new method is proposed for the imaging of the flux-line lattice of a type-II superconductor by soft X-ray absorption microscopy. It is shown that the method is very demanding but probably realisable in the foreseeable future. The new method has the potential to image in real space static and dynamical properties of the flux-line lattice at arbitrary external fields and with single-flux-line resolution.
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Affiliation(s)
- M Fähnle
- Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany.
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11
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Goering E, Bayer A, Gold S, Schütz G, Rabe M, Rüdiger U, Güntherodt G. Strong anisotropy of projected 3d moments in epitaxial CrO2 films. Phys Rev Lett 2002; 88:207203. [PMID: 12005597 DOI: 10.1103/physrevlett.88.207203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2001] [Indexed: 05/23/2023]
Abstract
Soft x-ray magnetic circular dichroism (XMCD) spectra have been investigated for different crystallographic projections of CrO2. Strong anisotropic orbital Cr 3d contributions and a change of sign of the XMCD signal is observed and attributed to t(2g) majority states near the Fermi level. Additionally, moment analysis exhibits anisotropic behavior in the projected spin contributions of CrO2 assigned to a strong magnetic dipole term T(z), consistent with an intrinsic magnetic easy axis behavior along the CrO2 [001] axis. A reduced projected isotropic Cr 3d spin moment has been interpreted in terms of hybridization with oxygen.
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Affiliation(s)
- E Goering
- MPI für Metallforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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Goering E, Gold S, Schütz G. HoFe - Garnet soft XMCD measurements below and above the compensation temperature. J Synchrotron Radiat 2001; 8:422-424. [PMID: 11512801 DOI: 10.1107/s0909049500018355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/22/2000] [Indexed: 05/23/2023]
Abstract
We have investigated the magnetism of Holmium-Iron-Garnet (Ho3Fe5O12) at the Ho M4,5 - the Fe L2,3 - and the O K - edges. As expected switching of the sub-lattice magnetization is observed at the compensation temperature. We will give detailed analysis ofthe Ho and Fe XMCD signals, using sum rules. Fe dichroism is analyzed in terms of 3d ground state moments and compared to Gadolinium-Iron-Garnet (Gd3Fe5O12). Contributions of octahedral and tetrahedral Fe sites could be separated and analyzed quantitatively. At the oxygen K edge two different structures are observable. Those structures show different temperature dependencies. Therefore we address these features separately to Fe and Rare Earth contributions.
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Affiliation(s)
- E Goering
- Lehrstuhl für Experimentalphysik IV, Universität Würzburg, Germany.
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13
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Weigand F, Goering E, Geissler J, Justen M, Dörr K, Ruck K, Schütz G. XMCD study of the Ruddlesden-Popper Phase La1.2Nd0.2Sr1.6Mn2O7. J Synchrotron Radiat 2001; 8:431-433. [PMID: 11512804 DOI: 10.1107/s0909049500016903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/10/2000] [Indexed: 05/23/2023]
Abstract
X-ray Magnetic Circular Dichroism (XMCD) measurements of the Ruddlesden-Popper Phase La1,2Nd0,2Sr1.6Mn2O7 are reported. The Mn K. La and Nd L2,L3 edges have been measured on a powder sample at two different magnetic fields at low temperature. The analysis of the spectra at B = 1T indicates a large orbital moment of the Nd 5d-states and a significant spin-polarization of the La 5d-band. Furthermore at the Mn K-edge a XMCD-signal is observed, showing a polarization of the Mn 4p-band. At lower field (0.2T) all XMCD-signals are about two times smaller corresponding to the lower total magnetization. The signal at the Nd L2 edge vanishes completely at 0.2T.
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Affiliation(s)
- F Weigand
- Lehrstuhl für Experimentelle Physik IV, Universität Würzburg, Germany.
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14
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Goering E, Gold S, Bayer A, Schuetz G. Non-symmetric influences in the total electron yield X-ray magnetic circular dichroism signal in applied magnetic fields. J Synchrotron Radiat 2001; 8:434-436. [PMID: 11512805 DOI: 10.1107/s0909049500018343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/22/2000] [Indexed: 05/23/2023]
Abstract
The total electron yield current is strongly influenced by external magnetic fields. As known before, this side effect can be slightly reduced by applied external bias voltages increasing the total sample drain current nearly up to saturation. Nevertheless those effects are not perfectly reduced in almost all X-ray Magnetic Circular Dichroism (XMCD) applications and are more prominent in very small XMCD signals, like O K edge spectra. We show that asymmetries in the total electron yield field response will result in XMCD offset signals, which are strongly photon energydependent and follow the nonmagnetic absorption signal. A simple but effective method to prevent those offset signals, is the use of asymmetric magnetic fields. A quantitative analysis and a numerical reduction method for those offset signals are shown.
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Affiliation(s)
- E Goering
- Lehrstuhl für Experimentalphysik IV, Universität Würzburg, Germany.
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15
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Goering E, Ahlers D, Attenkofer K, Obermeier G, Horn S, Schütz G. XMCD and magnetism of the ferrimagnetic system NaV6O11. J Synchrotron Radiat 1999; 6:537-539. [PMID: 15263372 DOI: 10.1107/s0909049598017543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1998] [Accepted: 12/14/1998] [Indexed: 05/24/2023]
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