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| Author | Juchtmans, R.; Verbeeck, J. | ||||
| Title | Local orbital angular momentum revealed by spiral-phase-plate imaging in transmission-electron microscopy | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical Review A | Abbreviated Journal  |
Phys Rev A |
| Volume | 93 | Issue | 93 | Pages | 023811 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The orbital angular momentum (OAM) of light and matter waves is a parameter that has been getting increasingly more attention over the past couple of years. Beams with a well-defined OAM, the so-called vortex beams, are applied already in, e.g., telecommunication, astrophysics, nanomanipulation, and chiral measurements in optics and electron microscopy. Also, the OAM of a wave induced by the interaction with a sample has attracted a lot of interest. In all these experiments it is crucial to measure the exact (local) OAM content of the wave, whether it is an incoming vortex beam or an exit wave after interacting with a sample. In this work we investigate the use of spiral phase plates (SPPs) as an alternative to the programmable phase plates used in optics to measure OAM. We derive analytically how these can be used to study the local OAM components of any wave function. By means of numerical simulations we illustrate how the OAM of a pure vortex beam can be measured. We also look at a sum of misaligned vortex beams and show how, by using SPPs, the position and the OAM of each individual beam can be detected. Finally, we look at the OAM induced by a magnetic dipole on a free-electron wave and show how the SPP can be used to localize the magnetic poles and measure their “magnetic charge.” Although our findings can be applied to study the OAM of any wave function, our findings are of particular interest for electron microscopy where versatile programmable phase plates do not yet exist. | ||||
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| Language | Wos | 000369367700006 | Publication Date | 2016-02-06 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
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| ISSN | 1050-2947;1094-1622; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.925 | Times cited | 12 | Open Access | |
| Notes | The authors acknowledge support from the Aspirant Fonds Wetenschappelijk Onderzoek–Vlaanderen (FPO), the EU un- der the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483- ESTEEM2, and the ERC Starting Grant 278510 VORTEX.; esteem2jra2 ECASJO; | Approved | Most recent IF: 2.925 | ||
| Call Number | c:irua:131613 c:irua:131613UA @ admin @ c:irua:131613 | Serial | 4030 | ||
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| Author | Clark, L.; Guzzinati, G.; Béché, A.; Lubk, A.; Verbeeck, J. | ||||
| Title | Symmetry-constrained electron vortex propagation | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review A | Abbreviated Journal |
Phys Rev A |
| Volume | 93 | Issue | 93 | Pages | 063840 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Electron vortex beams hold great promise for development in transmission electron microscopy but have yet to be widely adopted. This is partly due to the complex set of interactions that occur between a beam carrying orbital angular momentum (OAM) and a sample. Herein, the system is simplified to focus on the interaction between geometrical symmetries, OAM, and topology. We present multiple simulations alongside experimental data to study the behavior of a variety of electron vortex beams after interacting with apertures of different symmetries and investigate the effect on their OAM and vortex structure, both in the far field and under free-space propagation. | ||||
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| Language | Wos | 000378197200006 | Publication Date | 2016-06-23 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9926 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.925 | Times cited | 7 | Open Access | |
| Notes | L.C., A.B., G.G., and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 278510—VORTEX. J.V. and A.L. acknowledge financial support from the European Union through the 7th Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative (Reference No. 312483 ESTEEM2). The Qu-Ant-EM microscope was partly funded by the Hercules fund of the Flemish Government.; esteem2jra3; ECASJO; | Approved | Most recent IF: 2.925 | ||
| Call Number | c:irua:134086 c:irua:134086 | Serial | 4090 | ||
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| Author | Juchtmans, R.; Guzzinati, G.; Verbeeck, J. | ||||
| Title | Extension of Friedel's law to vortex-beam diffraction | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical Review A | Abbreviated Journal |
Phys Rev A |
| Volume | 94 | Issue | 94 | Pages | 033858 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Friedel's law states that the modulus of the Fourier transform of real functions is centrosymmetric, while the phase is antisymmetric. As a consequence of this, elastic scattering of plane-wave photons or electrons within the first-order Born-approximation, as well as Fraunhofer diffraction on any aperture, is bound to result in centrosymmetric diffraction patterns. Friedel's law, however, does not apply for vortex beams, and centrosymmetry in general is not present in their diffraction patterns. In this work we extend Friedel's law for vortex beams by showing that the diffraction patterns of vortex beams with opposite topological charge, scattered on the same two-dimensional potential, always are centrosymmetric to one another, regardless of the symmetry of the scattering object. We verify our statement by means of numerical simulations and experimental data. Our research provides deeper understanding in vortex-beam diffraction and can be used to design new experiments to measure the topological charge of vortex beams with diffraction gratings or to study general vortex-beam diffraction. | ||||
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| Language | Wos | 000384374500010 | Publication Date | 2016-09-30 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9926 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.925 | Times cited | 13 | Open Access | |
| Notes | The authors acknowledge support from the FWO (Aspirant Fonds Wetenschappelijk Onderzoek – Vlaanderen) and the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2 and ERC Starting Grant No. 278510 VORTEX.; ECASJO_; | Approved | Most recent IF: 2.925 | ||
| Call Number | EMAT @ emat @ c:irua:137200UA @ admin @ c:irua:137200 | Serial | 4314 | ||
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| Author | Juchtmans, R.; Clark, L.; Lubk, A.; Verbeeck, J. | ||||
| Title | Spiral phase plate contrast in optical and electron microscopy | Type | A1 Journal article | ||
| Year | 2016 | Publication | Physical review A | Abbreviated Journal |
Phys Rev A |
| Volume | 94 | Issue | 94 | Pages | 023838 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The use of phase plates in the back focal plane of a microscope is a well-established technique in optical microscopy to increase the contrast of weakly interacting samples and is gaining interest in electron microscopy as well. In this paper we study the spiral phase plate (SPP), also called helical, vortex, or two-dimensional Hilbert phase plate, which adds an angularly dependent phase of the form exp(iℓϕk) to the exit wave in Fourier space. In the limit of large collection angles, we analytically calculate that the average of a pair of l=+-1 SPP filtered images is directly proportional to the gradient squared of the exit wave, explaining the edge contrast previously seen in optical SPP work. We discuss the difference between a clockwise-anticlockwise pair of SPP filtered images and derive conditions under which the modulus of the wave's gradient can be seen directly from one SPP filtered image. This work provides the theoretical background to interpret images obtained with a SPP, thereby opening new perspectives for new experiments to study, for example, magnetic materials in an electron microscope. |
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| Language | Wos | 000381882800011 | Publication Date | 2016-08-22 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9926 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.925 | Times cited | 10 | Open Access | |
| Notes | The authors acknowledge support from the FWO (Aspirant Fonds Wetenschappelijk Onderzoek – Vlaanderen) and the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2 and ERC Starting Grant No. 278510 VORTEX.; ECASJO_ | Approved | Most recent IF: 2.925 | ||
| Call Number | EMAT @ emat @ c:irua:140086 | Serial | 4418 | ||
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| Author | Vávra, O.; Gaži, S.; Golubović, D.S.; Vávra, I.; Dérer, J.; Verbeeck, J.; Van Tendeloo, G.; Moshchalkov, V.V. | ||||
| Title | 0 and π phase Josephson coupling through an insulating barrier with magnetic impurities | Type | A1 Journal article | ||
| Year | 2006 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 74 | Issue | 2 | Pages | 020502 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | We have studied the temperature and field dependencies of the critical current I(C) in the Nb-Fe(0.1)Si(0.9)-Nb Josephson junction with a tunneling barrier formed by a paramagnetic insulator. We demonstrate that in these junctions coexistence of both the 0 and the pi states within one tunnel junction occurs, and leads to the appearance of a sharp cusp in the temperature dependence I(C)(T), similar to the I(C)(T) cusp found for the 0-pi transition in metallic pi junctions. This cusp is not related to the 0-pi temperature-induced transition itself, but is caused by the different temperature dependencies of the opposing 0 and pi supercurrents through the barrier. | ||||
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| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000239426600010 | Publication Date | 2006-07-15 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 27 | Open Access | |
| Notes | Approved | Most recent IF: 3.836; 2006 IF: 3.107 | |||
| Call Number | UA @ lucian @ c:irua:60087 c:irua:60087 c:irua:60087 c:irua:60087UA @ admin @ c:irua:60087 | Serial | 1 | ||
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| Author | Moshnyaga, V.; Gehrke, K.; Sudheendra, L.; Belenchuk, A.; Raabe, S.; Shapoval, O.; Verbeeck, J.; Van Tendeloo, G.; Samwer, K. | ||||
| Title | Electrical nonlinearity in colossal magnetoresistance manganite films: relevance of correlated polarons | Type | A1 Journal article | ||
| Year | 2009 | Publication | Physical review : B : solid state | Abbreviated Journal |
Phys Rev B |
| Volume | 79 | Issue | 13 | Pages | 134413,1-134413,8 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The metal-insulator (MI) transition in epitaxial thin films of La0.75Ca0.25MnO3 (LCMO) is accompanied by the appearance of an intrinsic electrical nonlinearity. The latter, probed by electrical third harmonic voltage, U3, or resistance, R3=dU3/dJ, is drastically enhanced in the vicinity of the MI transition, TMI=267 K. Applied magnetic field, B=5 T, suppresses the nonlinearity, resulting in a huge nonlinear CMR3(TMI)~105%. R3 shows a peculiar low-frequency (1 kHz) dependence, R3~(-0)n, with exponent, n, changing across the MI transition from n~1,52 for TTMI to n=1 (T<TMI). The observed electrical nonlinearity in LCMO reflects the behavior of correlated polarons, the number of which dramatically enhances in the vicinity of TMI. We argued that correlated polarons, considered as electric-elastic quadrupoles, provide a nonlinear (quadratic) coupling to the electric field, yielding a third harmonic electric nonlinearity in LCMO. The reference film of La0.7Sr0.3MnO3 (LSMO), a prototypic double exchange system with second-order phase transition, is characterized as a linear metallic material in the whole range of temperatures (T=10400 K), magnetic fields (B=05 T), and frequencies (=11000 Hz). | ||||
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| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000265942800074 | Publication Date | 2009-04-09 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 28 | Open Access | |
| Notes | Esteem 026019 | Approved | Most recent IF: 3.836; 2009 IF: 3.475 | ||
| Call Number | UA @ lucian @ c:irua:77022UA @ admin @ c:irua:77022 | Serial | 893 | ||
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| Author | Verbeeck, J.; Bals, S.; Lamoen, D.; Luysberg, M.; Huijben, M.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H.; Blank, D.H.A.; Van Tendeloo, G. | ||||
| Title | Electronic reconstruction at n-type SrTiO3/LaAlO3 interfaces | Type | A1 Journal article | ||
| Year | 2010 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 81 | Issue | 8 | Pages | 085113,1-085113,6 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Electron-energy-loss spectroscopy (EELS) is used to investigate single layers of LaAlO3 grown on SrTiO3 having an n-type interface as well as multilayers of LaAlO3 and SrTiO3 in which both n- and p-type interfaces occur. Only minor changes in Ti valence at the n-type interface are observed. This finding seems to contradict earlier experiments for other SrTiO3/LaAlO3 systems where large deviations in Ti valency were assumed to be responsible for the conductivity of these interfaces. Ab initio calculations have been carried out in order to interpret our EELS results. Using the concept of Bader charges, it is demonstrated that the so-called polar discontinuity is mainly resolved by lattice distortions and to a far lesser extent by changes in valency for both single layer and multilayer geometries. | ||||
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| Language | Wos | 000275053300040 | Publication Date | 2010-02-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 25 | Open Access | |
| Notes | Esteem 026019; Fwo | Approved | Most recent IF: 3.836; 2010 IF: 3.774 | ||
| Call Number | UA @ lucian @ c:irua:81768UA @ admin @ c:irua:81768 | Serial | 1005 | ||
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| Author | Dobrynin, A.N.; Ievlev, D.N.; Hendrich, C.; Temst, K.; Lievens, P.; Hörmann, U.; Verbeeck, J.; Van Tendeloo, G.; Vantomme, A. | ||||
| Title | Influence of finite size effects on exchange anisotropy in oxidized Co nanocluster assembled films | Type | A1 Journal article | ||
| Year | 2006 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 73 | Issue | 24 | Pages | 245416,1-8 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | We compare the magnetic properties of Co cluster assembled films with different degrees of oxidation. Clusters with grain size (2.3 +/- 0.7) nm are produced in a laser vaporization cluster source and soft-landed in ultrahigh vacuum conditions, forming highly porous nanogranular films. After exposure to air for different periods of time, the Co clusters oxidize and the sample may be considered as a thin antiferromagnetic Co oxide matrix containing ferromagnetic Co clusters. Magnetization measurements were performed in a temperature range from 300 down to 5 K, at applied magnetic fields up to 30 kOe. The exchange bias value at 5 K for the strongly oxidized sample is 4.8 kOe against the value of 0.75 kOe for the less oxidized sample. The mean values of the thicknesses of the Co oxide layers are estimated to be 0.6 and 0.3 nm for the more and less oxidized sample, respectively. We propose a method of measuring the exchange bias inducing temperature, i.e., the temperature at which exchange anisotropy is established. We determined the mean inducing temperatures for both samples, which are 55 and 25 K, respectively, for the more and less oxidized samples. Both temperatures are well below the bulk CoO Neel temperature of 292 K. A low value of the inducing temperature of the Co oxide layer is a consequence of its subnanometer thickness, while a large exchange bias value is a consequence of different dimensionality of Co clusters and Co oxide matrix. | ||||
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| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000238696900114 | Publication Date | 2006-06-16 | |
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 17 | Open Access | |
| Notes | Fwo; Gao; Iap; Hprn-Ct | Approved | Most recent IF: 3.836; 2006 IF: 3.107 | ||
| Call Number | UA @ lucian @ c:irua:59709UA @ admin @ c:irua:59709 | Serial | 1622 | ||
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| Author | Gehrke, K.; Moshnyaga, V.; Samwer, K.; Lebedev, O.I.; Verbeeck, J.; Kirilenko, D.; Van Tendeloo, G. | ||||
| Title | Interface controlled electronic variations in correlated heterostructures | Type | A1 Journal article | ||
| Year | 2010 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 82 | Issue | 11 | Pages | 113101,1-113101,4 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | An interface modification of (LaCa)MnO3-BaTiO3 superlattices was found to massively influence magnetic and magnetotransport properties. Moreover it determines the crystal structure of the manganite layers, changing it from orthorhombic (Pnma) for the conventional superlattice (cSL), to rhombohedral (R3̅ c) for the modified one (mSL). While the cSL shows extremely nonlinear ac transport, the mSL is an electrically homogeneous material. The observations go beyond an oversimplified picture of dead interface layers and evidence the importance of electronic correlations at perovskite interfaces. | ||||
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| Language | Wos | 000281643200001 | Publication Date | 2010-09-07 | |
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| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 9 | Open Access | |
| Notes | This work was supported by DFG via SFB 602, TPA2. | Approved | Most recent IF: 3.836; 2010 IF: 3.774 | ||
| Call Number | UA @ lucian @ c:irua:84249UA @ admin @ c:irua:84249 | Serial | 1691 | ||
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| Author | Tan, H.; Egoavil, R.; Béché, A.; Martinez, G.T.; Van Aert, S.; Verbeeck, J.; Van Tendeloo, G.; Rotella, H.; Boullay, P.; Pautrat, A.; Prellier, W. | ||||
| Title | Mapping electronic reconstruction at the metal-insulator interface in LaVO3/SrVO3 heterostructures | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 88 | Issue | 15 | Pages | 155123-155126 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | A (LaVO3)6/(SrVO3)(3) superlattice is studied with a combination of sub-A resolved scanning transmission electron microscopy and monochromated electron energy-loss spectroscopy. The V oxidation state is mapped with atomic spatial resolution enabling us to investigate electronic reconstruction at the LaVO3/SrVO3 interfaces. Surprisingly, asymmetric charge distribution is found at adjacent chemically symmetric interfaces. The local structure is proposed and simulated with a double channeling calculation which agrees qualitatively with our experiment. We demonstrate that local strain asymmetry is the likely cause of the electronic asymmetry of the interfaces. The electronic reconstruction at the interfaces extends much further than the chemical composition, varying from 0.5 to 1.2 nm. This distance corresponds to the length of charge transfer previously found in the (LaVO3)./(SrVO3). metal/insulating and the (LaAlO3)./(SrTiO3). insulating/insulating interfaces. | ||||
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| Language | Wos | 000326087100003 | Publication Date | 2013-10-21 | |
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| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 15 | Open Access | |
| Notes | Hercules; 246791 COUNTATOMS; 278510 VORTEX; 246102 IFOX; 312483 ESTEEM2; FWO; GOA XANES meets ELNES; esteem2jra3 ECASJO; | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
| Call Number | UA @ lucian @ c:irua:112733UA @ admin @ c:irua:112733 | Serial | 1944 | ||
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| Author | Schattschneider, P.; Schaffer, B.; Ennen, I.; Verbeeck, J. | ||||
| Title | Mapping spin-polarized transitions with atomic resolution | Type | A1 Journal article | ||
| Year | 2012 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 85 | Issue | 13 | Pages | 134422-134422,8 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The coupling of angstrom-sized electron probes with spin-polarized electronic transitions shows that the inelastically scattered probe electron is in a mixed state containing electron vortices with nonzero orbital angular momentum. These electrons create an asymmetric intensity distribution in energy filtered diffraction patterns, giving access to maps of the magnetic moments with atomic resolution. A feasibility experiment shows evidence of the predicted effect. Potential applications are column-by-column maps of magnetic ordering, and the creation of angstrom-sized free electrons with orbital angular momentum by inelastic scattering in a thin ferromagnetic foil. | ||||
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| Language | Wos | 000302608100004 | Publication Date | 2012-04-11 | |
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| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 41 | Open Access | |
| Notes | The authors thank A. Bleloch, S. Loffler, and P. Nellist for fruitful discussions and suggestions. P.S. acknowledges financial support from the Austrian Science Fund, Project No. I543-N20. The support of the EPSRC for the SuperSTEM facility is gratefully acknowledged. J.V. acknowledges support from the European Research Council under the 7th Framework Program (FP7), ERC Grant No. 246791-COUNTATOMS and ERC Starting Grant No. 278510-VORTEX. ECASJO_; | Approved | Most recent IF: 3.836; 2012 IF: 3.767 | ||
| Call Number | UA @ lucian @ c:irua:97390UA @ admin @ c:irua:97390 | Serial | 1945 | ||
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| Author | Boullay, P.; David, A.; Sheets, W.C.; Lüders, U.; Prellier, W.; Tan, H.; Verbeeck, J.; Van Tendeloo, G.; Gatel, C.; Vincze, G.; Radi, Z. | ||||
| Title | Microstructure and interface studies of LaVO3/SrVO3 superlattices | Type | A1 Journal article | ||
| Year | 2011 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 83 | Issue | 12 | Pages | 125403-125403,6 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The structure and interface characteristics of (LaVO3)6m(SrVO3)m superlattices deposited on a (100)-SrTiO3 substrate were studied using transmission electron microscopy (TEM). Cross-section TEM studies revealed that both LaVO3 (LVO) and SrVO3 (SVO) layers are good single-crystal quality and epitaxially grown with respect to the substrate. It is evidenced that LVO layers are made of two orientational variants of a distorted perovskite compatible with bulk LaVO3, while SVO layers suffers from a tetragonal distortion due to the substrate-induced stain. Electron energy loss spectroscopy investigations indicate changes in the fine structure of the V L23 edge, related to a valence change between the LaVO3 and the SrVO3 layers. | ||||
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| Language | Wos | 000288160300006 | Publication Date | 2011-03-09 | |
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| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 26 | Open Access | |
| Notes | Fwo; Esteem 026019 | Approved | Most recent IF: 3.836; 2011 IF: 3.691 | ||
| Call Number | UA @ lucian @ c:irua:88648UA @ admin @ c:irua:88648 | Serial | 2054 | ||
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| Author | Zhang, L.; Turner, S.; Brosens, F.; Verbeeck, J. | ||||
| Title | Model-based determination of dielectric function by STEM low-loss EELS | Type | A1 Journal article | ||
| Year | 2010 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 81 | Issue | 3 | Pages | 035102 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Theory of quantum systems and complex systems | ||||
| Abstract | Dielectric properties of materials are crucial in describing the electromagnetic response of materials. As devices are becoming considerably smaller than the optical wavelength, the conventional measuring methods based on optical response are limited by their spatial resolution. Electron energy loss spectroscopy performed in a scanning transmission electron microscope is a good alternative to obtain the dielectric properties with excellent spatial resolution. Due to the overlap of diffraction discs in scanning transmission electron microscopy, it is difficult to apply conventional experimental settings to suppress retardation losses. In this contribution, a relativistic dielectric model for the loss function is presented which is used in a model based optimization scheme to estimate the complex dielectric function of a material. The method is applied to experiments on bulk diamond and SrTiO3 and shows a good agreement with optical reference data when retardation effects are included. Application of this technique to nanoparticles is possible but several theoretical assumptions made in the model of the loss function are violated and interpretation becomes problematic. | ||||
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| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000274002300027 | Publication Date | 2010-01-08 | |
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| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 9 | Open Access | |
| Notes | Esteem – 026019; Fwo | Approved | Most recent IF: 3.836; 2010 IF: 3.774 | ||
| Call Number | UA @ lucian @ c:irua:81258UA @ admin @ c:irua:81258 | Serial | 2098 | ||
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| Author | Jorissen, K.; Rehr, J.J.; Verbeeck, J. | ||||
| Title | Multiple scattering calculations of relativistic electron energy loss spectra | Type | A1 Journal article | ||
| Year | 2010 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 81 | Issue | 15 | Pages | 155108,1-155108,6 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | A generalization of the real-space Greens-function approach is presented for ab initio calculations of relativistic electron energy loss spectra (EELS) which are particularly important in anisotropic materials. The approach incorporates relativistic effects in terms of the transition tensor within the dipole-selection rule. In particular, the method accounts for relativistic corrections to the magic angle in orientation resolved EELS experiments. The approach is validated by a study of the graphite C K edge, for which we present an accurate magic angle measurement consistent with the predicted value. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000277210500038 | Publication Date | 2010-04-13 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 24 | Open Access | |
| Notes | Fwo; Esteem 026019 | Approved | Most recent IF: 3.836; 2010 IF: 3.774 | ||
| Call Number | UA @ lucian @ c:irua:82805UA @ admin @ c:irua:82805 | Serial | 2230 | ||
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| Author | Schattschneider, P.; Verbeeck, J.; Mauchamp, V.; Jaouen, M.; Hamon, A.-L. | ||||
| Title | Real-space simulations of spin-polarized electronic transitions in iron | Type | A1 Journal article | ||
| Year | 2010 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 82 | Issue | 14 | Pages | 144418-144418,11 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | After the advent of energy-loss magnetic chiral dichroism (EMCD) in 2006, rapid progress in theoretical understanding and in experimental performance was achieved, recently demonstrating a spatial resolution of better than 2 nm. Similar to the x-ray magnetic circular dichroism technique, EMCD is used to study atom specific magnetic moments. The latest generation of electron microscopes opens the road to the mapping of spin moments on the atomic scale with this method. Here the theoretical background to reach this challenging aim is elaborated. Numerical simulations of the L3 transition in an Fe specimen, based on a combination of the density-matrix approach for inelastic electron scattering with the propagation of the probe electron in the lattice potential indicate the feasibility of single spin mapping in the electron microscope. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000282678900006 | Publication Date | 2010-10-08 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 11 | Open Access | |
| Notes | P.S. acknowledges the support of the Austrian Science Fund, Project No. I543-N20. | Approved | Most recent IF: 3.836; 2010 IF: 3.774 | ||
| Call Number | UA @ lucian @ c:irua:85029UA @ admin @ c:irua:85029 | Serial | 2832 | ||
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| Author | Zhang, L.; Erni, R.; Verbeeck, J.; Van Tendeloo, G. | ||||
| Title | Retrieving the dielectric function of diamond from valence electron energy-loss spectroscopy | Type | A1 Journal article | ||
| Year | 2008 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 77 | Issue | 19 | Pages | 195119,1-7 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | A data-acquisition and data-processing method is proposed that aims at minimizing the effect of retardation on the Kramers-Kronig analysis of valence electron energy-loss spectra. This method is applied to diamond, which, due to its high dielectric constant, is a material that shows strong retardation effects and thus is a challenging material to be studied by valence electron energy-loss spectroscopy. The results obtained show a significant improvement but still show small discrepancies with respect to optical data, which are most likely due to the residual retardation contributions and the fact that nonzero momentum transfers are measured. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000256971600055 | Publication Date | 2008-05-20 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 16 | Open Access | |
| Notes | Approved | Most recent IF: 3.836; 2008 IF: 3.322 | |||
| Call Number | UA @ lucian @ c:irua:70219UA @ admin @ c:irua:70219 | Serial | 2900 | ||
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| Author | Potapov, P.L.; Kulkova, S.E.; Schryvers, D.; Verbeeck, J. | ||||
| Title | Structural and chemical effects on EELS L3,2 ionization edges in Ni-based intermetallic compounds | Type | A1 Journal article | ||
| Year | 2001 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 64 | Issue | Pages | 184110,1-9 | |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | |||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000172239400038 | Publication Date | 2002-07-27 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 44 | Open Access | |
| Notes | Approved | Most recent IF: 3.836; 2001 IF: NA | |||
| Call Number | UA @ lucian @ c:irua:48393 | Serial | 3192 | ||
| Permanent link to this record | |||||
| Author | Turner, S.; Lebedev, O.I.; Verbeeck, J.; Gehrke, K.; Moshnyaga, V.; Van Tendeloo, G. | ||||
| Title | Structural phase transition and spontaneous interface reconstruction in La2/3Ca1/3MnO3/BaTiO3 superlattices | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 87 | Issue | 3 | Pages | 035418-8 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | (La2/3Ca1/3MnO3)n/(BaTiO3)m (LCMOn/BTOm) superlattices on MgO and SrTiO3 substrates with different layer thicknesses (n = 10, 38, 40 and m = 5, 18, 20) have been grown by metal organic aerosol deposition (MAD) and have been fully characterized down to the atomic scale to study the interface characteristics. Scanning transmission electron microscopy combined with spatially resolved electron energy-loss spectroscopy provides clear evidence for the existence of atomically sharp interfaces in MAD grown films, which exhibit epitaxial growth conditions, a uniform normal strain, and a fully oxidized state. Below a critical layer thickness the LCMO structure is found to change from the bulk Pnma symmetry to a pseudocubic R3̅ c symmetry. An atomically flat interface reconstruction consisting of a single Ca-rich atomic layer is observed on the compressively strained BTO on LCMO interface, which is thought to partially neutralize the total charge from the alternating polar atomic layers in LCMO as well as relieving strain at the interface. No interface reconstruction is observed at the tensile strained LCMO on BTO interface. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000313940400008 | Publication Date | 2013-01-23 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 12 | Open Access | |
| Notes | FWO; Hercules; Countatoms | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
| Call Number | UA @ lucian @ c:irua:106180 | Serial | 3245 | ||
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| Author | Lebedev, O.I.; Verbeeck, J.; Van Tendeloo, G.; Shapoval, O.; Belenchuk, A.; Moshnyaga, V.; Damaschke, B.; Samwer, K. | ||||
| Title | Structural phase transitions and stress accommodation in (La0.67Ca0.33MnO3)1.x:(MgO)x composite films | Type | A1 Journal article | ||
| Year | 2002 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 66 | Issue | 10 | Pages | 104421,1-10 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Composite (La0.67Ca0.33MnO3)(1-x):(MgO)(x) films were prepared by metalorganic aerosol deposition on a (100)MgO substrate for different concentrations of the (MgO) phase (0less than or equal toxless than or equal to0.8). At xapproximate to0.3 a percolation threshold in conductivity is reached, at which an infinite insulating MgO cluster forms around the La0.67Ca0.33MnO3 grains. This yields a drastic increase of the electrical resistance for films with x>0.3. The film structure is characterized by x-ray diffraction and transmission electron microscopy. The local structure of the La0.67Ca0.33MnO3 within the film depends on the MgO concentration which grows epitaxially along the domain boundaries. A different structural phase transition from the orthorhombic Pnma structure to an unusual rhombohedral R (3) over barc structure at the percolation threshold xapproximate to0.3 is found for La0.67Ca0.33MnO3. A three-dimensional stress accommodation in thick films through a phase transition is suggested. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000178460900060 | Publication Date | 2002-09-25 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0163-1829;1095-3795; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 48 | Open Access | |
| Notes | Approved | Most recent IF: 3.836; 2002 IF: NA | |||
| Call Number | UA @ lucian @ c:irua:54740 | Serial | 3250 | ||
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| Author | Verbeeck, J.; Lebedev, O.I.; Van Tendeloo, G.; Mercey, B. | ||||
| Title | SrTiO3(100)/(LaMnO3)m(SrMnO3)n layered heterostructures: a combined EELS and TEM study | Type | A1 Journal article | ||
| Year | 2002 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 66 | Issue | 18 | Pages | 184426 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Epitaxially grown heterostructures consisting of alternating layers of LaMnO(3) (LMO, 9 or 15 unit cells) and SrMnO(3) (SMO, 4 or 6 unit cells) on a SrTiO(3)(100) (STO(100)) substrate have been studied by a combination of high resolution transmission electron microscopy (HRTEM), electron diffraction, quantitative electron energy loss spectroscopy (EELS) with model fitting, energy filtered TEM (EFTEM) and imaging spectroscopy on an atomic scale. The combination of these techniques is necessary for the structural, chemical, and electronic characterization of these heterostructures. A model is proposed containing chemically and structurally sharp interfaces. The SrMnO(3) layers are stabilized in a Pm3m structure between two LMO layers. Tensile stress causes oxygen deficiency in the SMO layers increasing the number of 3d electrons on the Mn sites to resemble the Mn(3+) sites in LMO. The energy loss near edge structure (ELNES) of O and Mn is compared for both LMO and SMO layers and shows that the Mn-O bonds have a partially covalent character. The absence of a strong valency effect in the Mn ELNES is due to the oxygen vacancies in SMO. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Lancaster, Pa | Editor | ||
| Language | Wos | 000179633100062 | Publication Date | 2002-11-27 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0163-1829;1095-3795; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 32 | Open Access | |
| Notes | Approved | Most recent IF: 3.836; 2002 IF: NA | |||
| Call Number | UA @ lucian @ c:irua:54741 | Serial | 3563 | ||
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| Author | Juchtmans, R.; Béché, A.; Abakumov, A.; Batuk, M.; Verbeeck, J. | ||||
| Title | Using electron vortex beams to determine chirality of crystals in transmission electron microscopy | Type | A1 Journal article | ||
| Year | 2015 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 91 | Issue | 91 | Pages | 094112 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | We investigate electron vortex beams elastically scattered on chiral crystals. After deriving a general expression for the scattering amplitude of a vortex electron, we study its diffraction on point scatterers arranged on a helix. We derive a relation between the handedness of the helix and the topological charge of the electron vortex on one hand and the symmetry of the higher-order Laue zones in the diffraction pattern on the other for kinematically and dynamically scattered electrons. We then extend this to atoms arranged on a helix as found in crystals which belong to chiral space groups and propose a method to determine the handedness of such crystals by looking at the symmetry of the diffraction pattern. In contrast to alternative methods, our technique does not require multiple scattering, which makes it possible to also investigate extremely thin samples in which multiple scattering is suppressed. In order to verify the model, elastic scattering simulations are performed, and an experimental demonstration on Mn2Sb2O7 is given in which we find the sample to belong to the right-handed variant of its enantiomorphic pair. This demonstrates the usefulness of electron vortex beams to reveal the chirality of crystals in a transmission electron microscope and provides the required theoretical basis for further developments in this field. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000352017000002 | Publication Date | 2015-03-27 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 54 | Open Access | |
| Notes | Fwo; 312483 Esteem2; 278510 Vortex; esteem2jra1; esteem2jra2 ECASJO_; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
| Call Number | c:irua:125512 c:irua:125512 | Serial | 3825 | ||
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| Author | Juchtmans, R.; Verbeeck, J. | ||||
| Title | Orbital angular momentum in electron diffraction and its use to determine chiral crystal symmetries | Type | A1 Journal article | ||
| Year | 2015 | Publication | Physical review: B: condensed matter and materials physics | Abbreviated Journal |
Phys Rev B |
| Volume | 92 | Issue | 92 | Pages | 134108 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | In this work we present an alternative way to look at electron diffraction in a transmission electron microscope. Instead of writing the scattering amplitude in Fourier space as a set of plane waves,we use the cylindrical Fourier transform to describe the scattering amplitude in a basis of orbital angular momentum (OAM) eigenstates. We show how working in this framework can be very convenient when investigating, e.g., rotation and screw-axis symmetries. For the latter we find selection rules on the OAM coefficients that unambiguously reveal the handedness of the screw axis. Detecting the OAM coefficients of the scattering amplitude thus offers the possibility to detect the handedness of crystals without the need for dynamical simulations, the thickness of the sample, nor the exact crystal structure. We propose an experimental setup to measure the OAM components where an image of the crystal is taken after inserting a spiral phase plate in the diffraction plane and perform multislice simulations on α quartz to demonstrate how the method indeed reveals the chirality. The experimental feasibility of the technique is discussed together with its main advantages with respect to chirality determination of screw axes. The method shows how the use of a spiral phase plate can be extended from a simple phase imaging technique to a tool to measure the local OAM decomposition of an electron wave, widening the field of interest well beyond chiral space group determination. |
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000362893100002 | Publication Date | 2015-10-14 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121; 1550-235x | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 16 | Open Access | |
| Notes | The authors acknowledge support from the FWO (As- pirant Fonds Wetenschappelijk Onderzoek–Vlaanderen), the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2, and ERC Starting Grant No. 278510 VORTEX; esteem2jra1; ECASJO; | Approved | Most recent IF: 3.836; 2015 IF: 3.736 | ||
| Call Number | c:irua:129417 c:irua:129417UA @ admin @ c:irua:129417 | Serial | 4089 | ||
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| Author | Kleibert, A.; Balan, A.; Yanes, R.; Derlet, P.M.; Vaz, C.A.F.; Timm, M.; Fraile Rodríguez, A.; Béché, A.; Verbeeck, J.; Dhaka, R.S.; Radovic, M.; Nowak, U.; Nolting, F. | ||||
| Title | Direct observation of enhanced magnetism in individual size- and shape-selected 3d transition metal nanoparticles | Type | A1 Journal article | ||
| Year | 2017 | Publication | Physical review B | Abbreviated Journal |
Phys Rev B |
| Volume | 95 | Issue | 95 | Pages | 195404 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Magnetic nanoparticles are critical building blocks for future technologies ranging from nanomedicine to spintronics. Many related applications require nanoparticles with tailored magnetic properties. However, despite significant efforts undertaken towards this goal, a broad and poorly understood dispersion of magnetic properties is reported, even within monodisperse samples of the canonical ferromagnetic 3d transition metals. We address this issue by investigating the magnetism of a large number of size- and shape-selected, individual nanoparticles of Fe, Co, and Ni using a unique set of complementary characterization techniques. At room temperature, only superparamagnetic behavior is observed in our experiments for all Ni nanoparticles within the investigated sizes, which range from 8 to 20 nm. However, Fe and Co nanoparticles can exist in two distinct magnetic states at any size in this range: (i) a superparamagnetic state, as expected from the bulk and surface anisotropies known for the respective materials and as observed for Ni, and (ii) a state with unexpected stable magnetization at room temperature. This striking state is assigned to significant modifications of the magnetic properties arising from metastable lattice defects in the core of the nanoparticles, as concluded by calculations and atomic structural characterization. Also related with the structural defects, we find that the magnetic state of Fe and Co nanoparticles can be tuned by thermal treatment enabling one to tailor their magnetic properties for applications. This paper demonstrates the importance of complementary single particle investigations for a better understanding of nanoparticle magnetism and for full exploration of their potential for applications. | ||||
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| Language | Wos | 000400665300002 | Publication Date | 2017-05-05 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 21 | Open Access | OpenAccess |
| Notes | We thank A. Weber, R. Schelldorfer, and J. Krbanjevic (Paul Scherrer Institut) for technical assistance. This paper was supported by the Swiss Nanoscience Institute, University of Basel. A.F.R. acknowledges support from the MICIIN “Ramón y Cajal” Programme. A.B. and J.V. acknowledge funding from the European Union under the European Research Council (ERC) Starting Grant No. 278510 VORTEX and under a contract for Integrated Infrastructure Initiative ESTEEM2 No. 312483. R.Y. and U.N. thank the Deutsche Forschungsgemeinschaft for financial support via Sonderforschungsbereich 1214. Part of this work was performed at the Surface/Interface: Microscopy (SIM) beamline of the Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland. | Approved | Most recent IF: 3.836 | ||
| Call Number | EMAT @ emat @ c:irua:143634UA @ admin @ c:irua:143634 | Serial | 4575 | ||
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| Author | Das, S.; Rata, A.D.; Maznichenko, I., V; Agrestini, I.S.; Pippel, E.; Gauquelin, N.; Verbeeck, J.; Chen, K.; Valvidares, S.M.; Vasili, H.B.; Herrero-Martin, J.; Pellegrin, E.; Nenkov, K.; Herklotz, A.; Ernst, A.; Mertig, I.; Hu, Z.; Doerr, K. | ||||
| Title | Low-field switching of noncollinear spin texture at La0.7Sr0.3MnO3-SrRuO3interfaces | Type | A1 Journal article | ||
| Year | 2019 | Publication | Physical review B | Abbreviated Journal |
Phys Rev B |
| Volume | 99 | Issue | 2 | Pages | 024416 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Interfaces of ferroic oxides can show complex magnetic textures which have strong impact on spintronics devices. This has been demonstrated recently for interfaces with insulating antiferromagnets such as BiFeO3. Here, noncollinear spin textures which can be switched in very low magnetic field are reported for conducting ferromagnetic bilayers of La0.7Sr0.3MnO3-SrRuO3 (LSMO-SRO). The magnetic order and switching are fundamentally different for bilayers coherently grown in reversed stacking sequence. The SRO top layer forms a persistent exchange spring which is antiferromagnetically coupled to LSMO and drives switching in low fields of a few milliteslas. Density functional theory reveals the crucial impact of the interface termination on the strength of Mn-Ru exchange coupling across the interface. The observation of an exchange spring agrees with ultrastrong coupling for the MnO2/SrO termination. Our results demonstrate low-field switching of noncollinear spin textures at an interface between conducting oxides, opening a pathway for manipulating and utilizing electron transport phenomena in controlled spin textures at oxide interfaces. | ||||
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| Language | Wos | 000455821400005 | Publication Date | 2019-01-15 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 19 | Open Access | OpenAccess |
| Notes | ; The research in Halle was supported by Deutsche Forschungsgemeinschaft (DFG), SFB 762 Functional Oxide Interfaces (Projects No. A9 and No. B1). K.C. benefited from support of the DFG (Project 600575). Discussions with M. Trassin, M. Ziese, H. M. Christen, E.-J. Guo, F. Grcondciel, M. Bibes, and H. N. Lee are gratefully acknowledged. N. G. and J. V. acknowledge funding under the GOA project “Solarpaint” of the University of Antwerp. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. ; | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ admin @ c:irua:156717 | Serial | 5255 | ||
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| Author | Kuo, C.-T.; Lin, S.-C.; Ghiringhelli, G.; Peng, Y.; De Luca, G.M.; Di Castro, D.; Betto, D.; Gehlmann, M.; Wijnands, T.; Huijben, M.; Meyer-Ilse, J.; Gullikson, E.; Kortright, J.B.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Gerber, T.; Balestrino, G.; Brookes, N.B.; Braicovich, L.; Fadley, C.S. | ||||
| Title | Depth-resolved resonant inelastic x-ray scattering at a superconductor/half-metallic-ferromagnet interface through standing wave excitation | Type | A1 Journal article | ||
| Year | 2018 | Publication | Physical review B | Abbreviated Journal |
Phys Rev B |
| Volume | 98 | Issue | 23 | Pages | 235146 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | We demonstrate that combining standing wave (SW) excitation with resonant inelastic x-ray scattering (RIXS) can lead to depth resolution and interface sensitivity for studying orbital and magnetic excitations in correlated oxide heterostructures. SW-RIXS has been applied to multilayer heterostructures consisting of a superconductor La1.85Sr0.15CuO4 (LSCO) and a half-metallic ferromagnet La0.67Sr0.33MnO3 (LSMO). Easily observable SW effects on the RIXS excitations were found in these LSCO/LSMO multilayers. In addition, we observe different depth distribution of the RIXS excitations. The magnetic excitations are found to arise from the LSCO/LSMO interfaces, and there is also a suggestion that one of the dd excitations comes from the interfaces. SW-RIXS measurements of correlated-oxide and other multilayer heterostructures should provide unique layer-resolved insights concerning their orbital and magnetic excitations, as well as a challenge for RIXS theory to specifically deal with interface effects. | ||||
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| Language | Wos | 000454160800004 | Publication Date | 2018-12-21 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9969; 2469-9950 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 5 | Open Access | |
| Notes | J.V. and N.G. acknowledge ˝ funding through the GOA project “Solarpaint” of the University of Antwerp. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. | Approved | Most recent IF: 3.836 | ||
| Call Number | UA @ admin @ c:irua:156784 | Serial | 5363 | ||
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| Author | Savchenko, T.M.; Buzzi, M.; Howald, L.; Ruta, S.; Vijayakumar, J.; Timm, M.; Bracher, D.; Saha, S.; Derlet, P.M.; Béché, A.; Verbeeck, J.; Chantrell, R.W.; Vaz, C.A.F.; Nolting, F.; Kleibert, A. | ||||
| Title | Single femtosecond laser pulse excitation of individual cobalt nanoparticles | Type | A1 Journal article | ||
| Year | 2020 | Publication | Physical Review B | Abbreviated Journal |
Phys Rev B |
| Volume | 102 | Issue | 20 | Pages | 205418 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Laser-induced manipulation of magnetism at the nanoscale is a rapidly growing research topic with potential for applications in spintronics. In this work, we address the role of the scattering cross section, thermal effects, and laser fluence on the magnetic, structural, and chemical stability of individual magnetic nanoparticles excited by single femtosecond laser pulses. We find that the energy transfer from the fs laser pulse to the nanoparticles is limited by the Rayleigh scattering cross section, which in combination with the light absorption of the supporting substrate and protective layers determines the increase in the nanoparticle temperature. We investigate individual Co nanoparticles (8 to 20 nm in size) as a prototypical model system, using x-ray photoemission electron microscopy and scanning electron microscopy upon excitation with single femtosecond laser pulses of varying intensity and polarization. In agreement with calculations, we find no deterministic or stochastic reversal of the magnetization in the nanoparticles up to intensities where ultrafast demagnetization or all-optical switching is typically reported in thin films. Instead, at higher fluences, the laser pulse excitation leads to photo-chemical reactions of the nanoparticles with the protective layer, which results in an irreversible change in the magnetic properties. Based on our findings, we discuss the conditions required for achieving laser-induced switching in isolated nanomagnets. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000589602000005 | Publication Date | 2020-11-16 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record | |
| Impact Factor | 3.7 | Times cited | 1 | Open Access | OpenAccess |
| Notes | This work received funding by the Swiss National Foundation (SNF) (Grants No. 200021160186 and No. 2002153540), the Swiss Nanoscience Institute (SNI) (Grant No. SNI P1502), the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 737093 (FEMTOTERABYTE), and the COST Action CA17123 (MAGNETOFON). Part of this work was performed at the SIM beamline of the Swiss Light Source (SLS), Paul Scherrer Institut, Villigen, Switzerland. Part of the simulations were undertaken on the VIKING cluster, which is a high-performance compute facility provided by the University of York. We kindly acknowledge Anja Weber from PSI for preparation of substrates with marker structures. A.B. and Jo Verbeeck acknowledge funding through FWO Project No. G093417N (“Compressed sensing enabling low dose imaging in transmission electron microscopy”) from the Flanders Research Fund. Jo Verbeeck acknowledges funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 823717 – ESTEEM3. S.S. acknowledges ETH Zurich Post-Doctoral fellowship and Marie Curie actions for people COFUND program.; esteem3JRA; esteem3reported | Approved | Most recent IF: 3.7; 2020 IF: 3.836 | ||
| Call Number | EMAT @ emat @c:irua:174273 | Serial | 6669 | ||
| Permanent link to this record | |||||
| Author | Tan, H.; Turner, S.; Yucelen, E.; Verbeeck, J.; Van Tendeloo, G. | ||||
| Title | 2D atomic mapping of oxidation states in transition metal oxides by scanning transmission electron microscopy and electron energy-loss spectroscopy : reply | Type | Editorial | ||
| Year | 2012 | Publication | Physical review letters | Abbreviated Journal |
Phys Rev Lett |
| Volume | 108 | Issue | 25 | Pages | 259702 |
| Keywords | Editorial; Electron microscopy for materials research (EMAT) | ||||
| Abstract | |||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000305568700038 | Publication Date | 2012-06-19 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9007 | ISBN | Additional Links | UA library record; WoS full record | |
| Impact Factor | 8.462 | Times cited | Open Access | ||
| Notes | Approved | Most recent IF: 8.462; 2012 IF: 7.943 | |||
| Call Number | UA @ admin @ c:irua:100293 | Serial | 5370 | ||
| Permanent link to this record | |||||
| Author | Tan, H.; Turner, S.; Yücelen, E.; Verbeeck, J.; Van Tendeloo, G. | ||||
| Title | 2D atomic mapping of oxidation states in transition metal oxides by scanning transmission electron microscopy and electron energy-loss spectroscopy | Type | A1 Journal article | ||
| Year | 2011 | Publication | Physical review letters | Abbreviated Journal |
Phys Rev Lett |
| Volume | 107 | Issue | 10 | Pages | 107602 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Using a combination of high-angle annular dark-field scanning transmission electron microscopy and atomically resolved electron energy-loss spectroscopy in an aberration-corrected transmission electron microscope we demonstrate the possibility of 2D atom by atom valence mapping in the mixed valence compound Mn3O4. The Mn L2,3 energy-loss near-edge structures from Mn2+ and Mn3+ cation sites are similar to those of MnO and Mn2O3 references. Comparison with simulations shows that even though a local interpretation is valid here, intermixing of the inelastic signal plays a significant role. This type of experiment should be applicable to challenging topics in materials science, such as the investigation of charge ordering or single atom column oxidation states in, e.g., dislocations. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | New York, N.Y. | Editor | ||
| Language | Wos | 000294406600018 | Publication Date | 2011-09-01 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9007;1079-7114; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 8.462 | Times cited | 115 | Open Access | |
| Notes | Esteem 026019; Fwo | Approved | Most recent IF: 8.462; 2011 IF: 7.370 | ||
| Call Number | UA @ lucian @ c:irua:91265 c:irua:91265 c:irua:91265UA @ admin @ c:irua:91265 | Serial | 5 | ||
| Permanent link to this record | |||||
| Author | da Pieve, F.; Hogan, C.; Lamoen, D.; Verbeeck, J.; Vanmeert, F.; Radepont, M.; Cotte, M.; Janssens, K.; Gonze, X.; Van Tendeloo, G. | ||||
| Title | Casting light on the darkening of colors in historical paintings | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review letters | Abbreviated Journal |
Phys Rev Lett |
| Volume | 111 | Issue | 20 | Pages | 208302-208305 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) | ||||
| Abstract | The degradation of colors in historical paintings affects our cultural heritage in both museums and archeological sites. Despite intensive experimental studies, the origin of darkening of one of the most ancient pigments known to humankind, vermilion (α-HgS), remains unexplained. Here, by combining many-body theoretical spectroscopy and high-resolution microscopic x-ray diffraction, we clarify the composition of the damaged paint work and demonstrate possible physicochemical processes, induced by illumination and exposure to humidity and air, that cause photoactivation of the original pigment and the degradation of the secondary minerals. The results suggest a new path for the darkening process which was never considered by previous studies and prompt a critical examination of their findings. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | New York, N.Y. | Editor | ||
| Language | Wos | 000327244500003 | Publication Date | 2013-11-15 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9007;1079-7114; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 8.462 | Times cited | 30 | Open Access | |
| Notes | Vortex; ERC FP7; COUNTATOMS; ECASJO_; | Approved | Most recent IF: 8.462; 2013 IF: 7.728 | ||
| Call Number | UA @ lucian @ c:irua:111396UA @ admin @ c:irua:111396 | Serial | 287 | ||
| Permanent link to this record | |||||
| Author | Schattschneider, P.; Löffler, S.; Verbeeck, J. | ||||
| Title | Comment on “Quantized orbital angular momentum transfer and magnetic dichroism in the interaction of electron vortices with matter” | Type | Editorial | ||
| Year | 2013 | Publication | Physical review letters | Abbreviated Journal |
Phys Rev Lett |
| Volume | 110 | Issue | 18 | Pages | 189501-189502 |
| Keywords | Editorial; Electron microscopy for materials research (EMAT) | ||||
| Abstract | |||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | New York, N.Y. | Editor | ||
| Language | Wos | 000319019300019 | Publication Date | 2013-05-02 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9007;1079-7114; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 8.462 | Times cited | 8 | Open Access | |
| Notes | Countatoms; Vortex; Esteem2; esteem2jra3 ECASJO; | Approved | Most recent IF: 8.462; 2013 IF: 7.728 | ||
| Call Number | UA @ lucian @ c:irua:109014UA @ admin @ c:irua:109014 | Serial | 410 | ||
| Permanent link to this record | |||||