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Author |
Conings, B.; Babayigit, A.; Klug, M.; Bai, S.; Gauquelin, N.; Sakai, N.; Wang, J.T.-W.; Verbeeck, J.; Boyen, H.-G.; Snaith, H. |
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Title |
Getting rid of anti-solvents: gas quenching for high performance perovskite solar cells |
Type |
P1 Proceeding |
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Year |
2018 |
Publication |
2018 Ieee 7th World Conference On Photovoltaic Energy Conversion (wcpec)(a Joint Conference Of 45th Ieee Pvsc, 28th Pvsec & 34th Eu Pvsec) |
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Keywords |
P1 Proceeding; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
As the field of perovskite optoelectronics developed, a plethora of strategies has arisen to control their electronic and morphological characteristics for the purpose of producing high efficiency devices. Unfortunately, despite this wealth of deposition approaches, the community experiences a great deal of irreproducibility between different laboratories, batches and preparation methods. Aiming to address this issue, we developed a simple deposition method based on gas quenching that yields smooth films for a wide range of perovskite compositions, in single, double, triple and quadruple cation varieties, and produces planar heterojunction devices with competitive efficiencies, so far up to 20%. |
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Wos  |
000469200401163 |
Publication Date |
2018-12-08 |
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Series Issue |
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Edition |
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ISSN |
978-1-5386-8529-7 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:160468 |
Serial |
5365 |
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Author |
Wang, J.; Shin, Y.; Gauquelin, N.; Yang, Y.; Lee, C.; Jannis, D.; Verbeeck, J.; Rondinelli, J.M.; May, S.J. |
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Title |
Physical properties of epitaxial SrMnO2.5−δFγoxyfluoride films |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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Volume |
31 |
Issue |
36 |
Pages |
365602 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Recently, topotactic fluorination has become an alternative way of doping epitaxial perovskite oxides through anion substitution to engineer their electronic properties instead of the more commonly used cation substitution. In this work, epitaxial oxyfluoride SrMnO2.5−δ F γ films were synthesized via topotactic fluorination of SrMnO2.5 films using polytetrafluoroethylene as the fluorine source. Oxidized SrMnO3 films were also prepared for comparison with the fluorinated samples. The F content, probed by x-ray photoemission spectroscopy, was systematically controlled by adjusting fluorination conditions. Electronic transport measurements reveal that increased F content (up to γ = 0.14) systematically increases the electrical resistivity, despite the nominal electron-doping induced by F substitution for O in these films. In contrast, oxidized SrMnO3 exhibits a decreased resistivity and conduction activation energy. A blue-shift of optical absorption features occurs with increasing F content. Density functional theory calculations indicate that F acts as a scattering center for electronic transport, controls the observed weak ferromagnetic behavior of the films, and reduces the inter-band optical transitions in the manganite films. These results stand in contrast to bulk electron-doped La1−x Ce x MnO3, illustrating how aliovalent anionic substitutions can yield physical behavior distinct from A-site substituted perovskites with the same nominal B-site oxidation states. |
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Wos |
000472232000002 |
Publication Date |
2019-09-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.649 |
Times cited |
5 |
Open Access |
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Notes |
Work at Drexel was supported by the National Science Foundation (NSF), grant number CMMI-1562223. Thin film synthesis utilized deposition instrumentation acquired through an Army Research Office DURIP grant (W911NF-14-1-0493). Y.S and J.M.R. were supported by NSF (Grant No. DMR-1454688). Calculations were performed using the QUEST HPC Facility at Northwestern, the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF Grant No. ACI-1053575, and the Center for Nanoscale Materials (Carbon Cluster). Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. J.V. and N. G. acknowledge funding from a GOA project “Solarpaint” of the University of Antwerp. D.J. acknowledges funding from FWO project G093417N from the Flemish fund for scientific research. |
Approved |
Most recent IF: 2.649 |
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Call Number |
EMAT @ emat @UA @ admin @ c:irua:161174 |
Serial |
5293 |
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Author |
Guzzinati, G.; Ghielens, W.; Mahr, C.; Béché, A.; Rosenauer, A.; Calders, T.; Verbeeck, J. |
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Title |
Electron Bessel beam diffraction for precise and accurate nanoscale strain mapping |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
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Volume |
114 |
Issue |
24 |
Pages |
243501 |
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Keywords |
A1 Journal article; ADReM Data Lab (ADReM); Electron microscopy for materials research (EMAT) |
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Abstract |
Strain has a strong effect on the properties of materials and the performance of electronic devices. Their ever shrinking size translates into a constant demand for accurate and precise measurement methods with a very high spatial resolution. In this regard, transmission electron microscopes are key instruments thanks to their ability to map strain with a subnanometer resolution. Here, we present a method to measure strain at the nanometer scale based on the diffraction of electron Bessel beams. We demonstrate that our method offers a strain sensitivity better than 2.5 × 10−4 and an accuracy of 1.5 × 10−3, competing with, or outperforming, the best existing methods with a simple and easy to use experimental setup. |
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Wos |
000472599100019 |
Publication Date |
2019-06-17 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-6951 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.411 |
Times cited |
17 |
Open Access |
OpenAccess |
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Notes |
Deutsche Forschungsgemeinschaft, RO2057/12-2 ; Fonds Wetenschappelijk Onderzoek, G.0934.17N ; |
Approved |
Most recent IF: 3.411 |
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Call Number |
EMAT @ emat @UA @ admin @ c:irua:160119 |
Serial |
5181 |
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Author |
Bouwmeester, R.L.; de Hond, K.; Gauquelin, N.; Verbeeck, J.; Koster, G.; Brinkman, A. |
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Title |
Stabilization of the perovskite phase in the Y-Bi-O system by using a BaBiO₃ buffer layer |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Physica status solidi: rapid research letters |
Abbreviated Journal |
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Volume |
13 |
Issue |
7 |
Pages |
1800679 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A topological insulating phase has theoretically been predicted for the thermodynamically unstable perovskite phase of YBiO3. Here, it is shown that the crystal structure of the Y-Bi-O system can be controlled by using a BaBiO3 buffer layer. The BaBiO3 film overcomes the large lattice mismatch of 12% with the SrTiO3 substrate by forming a rocksalt structure in between the two perovskite structures. Depositing an YBiO3 film directly on a SrTiO3 substrate gives a fluorite structure. However, when the Y-Bi-O system is deposited on top of the buffer layer with the correct crystal phase and comparable lattice constant, a single oriented perovskite structure with the expected lattice constants is observed. |
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Wos |
000477671800005 |
Publication Date |
2019-03-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1862-6254 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
11 |
Open Access |
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Notes |
The work at the University of Twente is financially supported by NWO through a VICI grant. N.G. and J.V. acknowledge financial support from the GOA project “Solarpaint” of the University of Antwerp. The microscope used for this experiment has been partially financed by the Hercules Fund from the Flemish Government. L. Ding is acknowledge for his help with the GPA analysis. |
Approved |
no |
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Call Number |
UA @ admin @ c:irua:181236 |
Serial |
6889 |
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Author |
Vanrompay, H.; Béché, A.; Verbeeck, J.; Bals, S. |
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Title |
Experimental Evaluation of Undersampling Schemes for Electron Tomography of Nanoparticles |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Particle and particle systems characterization |
Abbreviated Journal |
Part Part Syst Char |
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Volume |
36 |
Issue |
36 |
Pages |
1900096 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
One of the emerging challenges in the field of 3D characterization of nanoparticles by electron tomography is to avoid degradation and deformation of the samples during the acquisition of a tilt series. In order to reduce the required electron dose, various undersampling approaches have been proposed. These methods include lowering the number of 2D projection images, reducing the probe current during the acquisition, and scanning a smaller number of pixels in the 2D images. A comparison is made between these approaches based on tilt series acquired for a gold nanoparticle. |
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Wos |
000477679400014 |
Publication Date |
2019-05-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0934-0866 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.474 |
Times cited |
12 |
Open Access |
Not_Open_Access |
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Notes |
H.V. acknowledges financial support by the Research Foundation Flanders (FWO Grant No. 1S32617N). A.B. and J.V. acknowledge FWO project 6093417N “Compressed sensing enabling low dose imaging in STEM.” The authors thank G. González-Rubio, A. Sánchez-Iglesias, and L.M. Liz-Marzán for provision of the samples. |
Approved |
Most recent IF: 4.474 |
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Call Number |
EMAT @ emat @UA @ admin @ c:irua:159986 |
Serial |
5175 |
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Author |
Van den Broek, W.; Reed, B.W.; Béché, A.; Velazco, A.; Verbeeck, J.; Koch, C.T. |
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Title |
Various compressed sensing setups evaluated against Shannon sampling under constraint of constant illumination |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
IEEE transactions on computational imaging |
Abbreviated Journal |
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Volume |
5 |
Issue |
3 |
Pages |
502-514 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Under the constraint of constant illumination, an information criterion is formulated for the Fisher information that compressed sensing measurements in optical and transmission electron microscopy contain about the underlying parameters. Since this approach requires prior knowledge of the signal's support in the sparse basis, we develop a heuristic quantity, the detective quantum efficiency (DQE), that tracks this information criterion well without this knowledge. In this paper, it is shown that for the investigated choice of sensing matrices, and in the absence of read-out noise, i.e., with only Poisson noise present, compressed sensing does not raise the amount of Fisher information in the recordings above that of Shannon sampling. Furthermore, enabled by the DQE's analytical tractability, the experimental designs are optimized by finding out the optimal fraction of on pixels as a function of dose and read-out noise. Finally, we introduce a regularization and demonstrate, through simulations and experiment, that it yields reconstructions attaining minimum mean squared error at experimental settings predicted by the DQE as optimal. |
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Corporate Author |
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Place of Publication |
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Wos |
000480352600013 |
Publication Date |
2019-01-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2333-9403 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.546 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by the Hercules fund from the Flemish Government (Qu-Ant-EM microscope used for the experimental data). The work of W. Van den Broek was supported by the DFG under Grant BR 5095/2-1 (Compressed sensing in ptychography and transmission electron microscopy). The work of A. Beche, A. Velazco, and J. Verbeeck was supported by the FWO under Grant G093417N (Compressed sensing enabling low dose imaging in transmission electron microscopy). The work of Christoph T. Koch was supported by the DFG under Grant CRC 951. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Chrysanthe Preza. ; |
Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:161792 |
Serial |
5368 |
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Author |
Yu, S.; Sankaran, K.J.; Korneychuk, S.; Verbeeck, J.; Haenen, K.; Jiang, X.; Yang, N. |
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Title |
High-performance supercabatteries using graphite@diamond nano-needle capacitor electrodes and redox electrolytes |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
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Volume |
11 |
Issue |
38 |
Pages |
17939-17946 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Supercabatteries have the characteristics of supercapacitors and batteries, namely high power and energy densities as well as long cycle life. To construct them, capacitor electrodes with wide potential windows and/or redox electrolytes are required. Herein, graphite@diamond nano-needles and an aqueous solution of Fe(CN)(6)(3-/4-) are utilized as the capacitor electrode and the electrolyte, respectively. This diamond capacitor electrode has a nitrogen-doped diamond core and a nano-graphitic shell. In 0.05 M Fe(CN)(6)(3-/4-) + 1.0 M Na2SO4 aqueous solution, the fabricated supercabattery has a capacitance of 66.65 mF cm(-2) at a scan rate of 10 mV s(-1). It is stable over 10 000 charge/discharge cycles. The symmetric supercabattery device assembled using a two-electrode system possesses energy and power densities of 10.40 W h kg(-1) and 6.96 kW kg(-1), respectively. These values are comparable to those of other energy storage devices. Therefore, diamond supercabatteries are promising for many industrial applications. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000489646900036 |
Publication Date |
2019-09-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2040-3364 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.367 |
Times cited |
26 |
Open Access |
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Notes |
; S. Yu and K. J. Sankaran contributed equally to this work. N. Yang acknowledges funding from the German Science Foundation under the project of YA344/1-1. J. Verbeeck and S. Korneychuk acknowledge the funding from 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. K. J. Sankaran and K. Haenen like to acknowledge the financial support of the Methusalem “NANO” network. S. Yu likes to acknowledge the financial support from fundamental research funds for the central universities (Grant No. SWU019001). ; |
Approved |
Most recent IF: 7.367 |
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Call Number |
UA @ admin @ c:irua:163723 |
Serial |
5388 |
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Author |
Guzzinati, G.; Béché, A.; McGrouther, D.; Verbeeck, J. |
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Title |
Prospects for out-of-plane magnetic field measurements through interference of electron vortex modes in the TEM |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Journal of optics |
Abbreviated Journal |
J Optics-Uk |
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Volume |
21 |
Issue |
12 |
Pages |
124002 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Magnetic field mapping in transmission electron microscopy is commonplace, but all conventional methods provide only a projection of the components of the magnetic induction perpendicular to the electron trajectory. Recent experimental advances with electron vortices have shown that it is possible to map the out of plane magnetic induction in a TEM setup via interferometry with a specifically prepared electron vortex state carrying high orbital angular momentum (OAM). The method relies on the Aharonov?Bohm phase shift that the electron undergoes when going through a longitudinal field. Here we show how the same effect naturally occurs for any electron wave function, which can always be described as a superposition of OAM modes. This leads to a clear connection between the occurrence of high-OAM partial waves and the amount of azimuthal rotation in the far field angular distribution of the beam. We show that out of plane magnetic field measurement can thus be obtained with a much simpler setup consisting of a ring-like aperture with azimuthal spokes. We demonstrate the experimental setup and explore the achievable sensitivity of the magnetic field measurement. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000499367800001 |
Publication Date |
2019-10-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2040-8978 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.741 |
Times cited |
3 |
Open Access |
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Notes |
The authors thank V Grillo and T Harvey for interesting and fruitful discussion. GG acknowledges support from a postdoctoral fellow-ship grant from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO). The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. AB acknowledges funding from FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy'). DM gratefully acknowledges funding of the FEBID capability through joint funding by University of Glasgow & EPSRC through a Strategic Equipment Grant (EP/P001483/1). |
Approved |
Most recent IF: 1.741 |
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Call Number |
UA @ admin @ c:irua:165116 |
Serial |
6319 |
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Author |
Wang, J.; Nguyen, M.D.; Gauquelin, N.; Verbeeck, J.; Do, M.T.; Koster, G.; Rijnders, G.; Houwman, E. |
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Title |
On the importance of the work function and electron carrier density of oxide electrodes for the functional properties of ferroelectric capacitors |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Physica Status Solidi-Rapid Research Letters |
Abbreviated Journal |
Phys Status Solidi-R |
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Volume |
14 |
Issue |
14 |
Pages |
1900520 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
It is important to understand the effect of the interfaces between the oxide electrode layers and the ferroelectric layer on the polarization response for optimizing the device performance of all-oxide ferroelectric devices. Herein, the effects of the oxide La0.07Ba0.93SnO3 (LBSO) as an electrode material in an PbZr0.52Ti0.48O3 (PZT) ferroelectric capacitor are compared with those of the more commonly used SrRuO3 (SRO) electrode. SRO (top)/PZT/SRO (bottom), SRO/PZT/LBSO, and SRO/PZT/2 nm SRO/LBSO devices are fabricated. Only marginal differences in crystalline properties, determined by X-ray diffraction and scanning transmission electron microscopy, are found. High-quality polarization loops are obtained, but with a much larger coercive field for the SRO/PZT/LBSO device. In contrast to the SRO/PZT/SRO device, the polarization decreases strongly with increasing field cycling. This fatigue problem can be remedied by inserting a 2 nm SRO layer between PZT and LBSO. It is argued that strongly increased charge injection into the PZT occurs at the bottom interface, because of the low PZT/LBSO interfacial barrier and the much lower carrier density in LBSO, as compared with that in SRO, causing a low dielectric constant, depleted layer in LBSO. The charge injection creates a trapped space charge in the PZT, causing the difference in fatigue behavior. |
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Place of Publication |
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Editor |
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Language |
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Wos |
000506195600001 |
Publication Date |
2019-12-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1862-6254 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.8 |
Times cited |
6 |
Open Access |
OpenAccess |
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Notes |
; This work was supported by Nederlandse Organisatie voor Wetenschappelijk Onderzoek through grant no.13HTSM01. ; |
Approved |
Most recent IF: 2.8; 2020 IF: 3.032 |
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Call Number |
UA @ admin @ c:irua:165681 |
Serial |
6316 |
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Author |
Spreitzer, M.; Klement, D.; Egoavil, R.; Verbeeck, J.; Kovac, J.; Zaloznik, A.; Koster, G.; Van Tendeloo, G.; Suvorov, D.; Rijnders, G. |
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Title |
Growth mechanism of epitaxial SrTiO3 on a (1 x 2) + (2 x 1) reconstructed Sr(1/2 ML)/Si(001) surface |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Materials Chemistry C |
Abbreviated Journal |
J Mater Chem C |
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Volume |
8 |
Issue |
2 |
Pages |
518-527 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Sub-monolayer control over the growth at silicon-oxide interfaces is a prerequisite for epitaxial integration of complex oxides with the Si platform, enriching it with a variety of functionalities. However, the control over this integration is hindered by the intense reaction of the constituents. The most suitable buffer material for Si passivation is metallic strontium. When it is overgrown with a layer of SrTiO3 (STO) it can serve as a pseudo-substrate for the integration with functional oxides. In our study we determined a mechanism for epitaxial integration of STO with a (1 x 2) + (2 x 1) reconstructed Sr(1/2 ML)/Si(001) surface using all-pulsed laser deposition (PLD) technology. A detailed analysis of the initial deposition parameters was performed, which enabled us to develop a complete protocol for integration, taking into account the peculiarities of the PLD growth, STO critical thickness, and process thermal budget, in order to kinetically trap the reaction between STO and Si and thus to minimize the thickness of the interface layer. The as-prepared oxide layer exhibits STO(001)8Si(001) out-of-plane and STO[110]8Si[100] in-plane orientation and together with recent advances in large-scale PLD tools these results represent a new technological solution for the implementation of oxide electronics on demand. |
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Wos |
000506852400036 |
Publication Date |
2019-10-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2050-7526; 2050-7534 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.4 |
Times cited |
12 |
Open Access |
OpenAccess |
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Notes |
; The research was financially supported by the Slovenian Research Agency (Project No. P2-0091, J2-9237) and Ministry of Education, Science and Sport of the Republic of Slovenia (SIOX projects). This work was also funded by the European Union Council under the 7th Framework Program grant no. NMP3-LA-2010-246102 IFOX. J. V. and G. V. T. acknowledge funding from the Fund for Scientific Research Flanders under project no. G.0044.13N. ; |
Approved |
Most recent IF: 6.4; 2020 IF: 5.256 |
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Call Number |
UA @ admin @ c:irua:165672 |
Serial |
6298 |
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| Permanent link to this record |
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Author |
Araizi-Kanoutas, G.; Geessinck, J.; Gauquelin, N.; Smit, S.; Verbeek, X.H.; Mishra, S.K.; Bencok, P.; Schlueter, C.; Lee, T.-L.; Krishnan, D.; Fatermans, J.; Verbeeck, J.; Rijnders, G.; Koster, G.; Golden, M.S. |
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Title |
Co valence transformation in isopolar LaCoO3/LaTiO3 perovskite heterostructures via interfacial engineering |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
Phys. Rev. Materials |
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| |
Volume |
4 |
Issue |
2 |
Pages |
026001 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We report charge transfer up to a single electron per interfacial unit cell across nonpolar heterointerfaces from the Mott insulator LaTiO3 to the charge transfer insulator LaCoO3. In high-quality bi- and trilayer systems grown using pulsed laser deposition, soft x-ray absorption, dichroism, and scanning transmission electron microscopy-electron energy loss spectroscopy are used to probe the cobalt-3d electron count and provide an element-specific investigation of the magnetic properties. The experiments show the cobalt valence conversion is active within 3 unit cells of the heterointerface, and able to generate full conversion to 3d7 divalent Co, which displays a paramagnetic ground state. The number of LaTiO3/LaCoO3 interfaces, the thickness of an additional, electronically insulating “break” layer between the LaTiO3 and LaCoO3, and the LaCoO3 film thickness itself in trilayers provide a trio of control knobs for average charge of the cobalt ions in LaCoO3, illustrating the efficacy of O−2p band alignment as a guiding principle for property design in complex oxide heterointerfaces. |
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Place of Publication |
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Editor |
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Language |
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Wos |
000513551200007 |
Publication Date |
2020-02-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.4 |
Times cited |
13 |
Open Access |
OpenAccess |
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Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Universiteit Antwerpen; Horizon 2020, 730872 ; Department of Science and Technology, Ministry of Science and Technology, SR/NM/Z-07/2015 ; Jawaharlal Nehru Centre for Advanced Scientific Research; |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
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Call Number |
EMAT @ emat @c:irua:167787 |
Serial |
6376 |
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| Permanent link to this record |
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Author |
Chen, B.; Gauquelin, N.; Reith, P.; Halisdemir, U.; Jannis, D.; Spreitzer, M.; Huijben, M.; Abel, S.; Fompeyrine, J.; Verbeeck, J.; Hilgenkamp, H.; Rijnders, G.; Koster, G. |
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Title |
Thermal-strain-engineered ferromagnetism of LaMnO3/SrTiO3 heterostructures grown on silicon |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
Phys. Rev. Materials |
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| |
Volume |
4 |
Issue |
2 |
Pages |
024406 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The integration of oxides on Si remains challenging, which largely hampers the practical applications of oxide-based electronic devices with superior performance. Recently, LaMnO3/SrTiO3 (LMO/STO) heterostructures have gained renewed interest for the debating origin of the ferromagnetic-insulating ground state as well as for their spin-filter applications. Here we report on the structural and magnetic properties of high-quality LMO/STO heterostructures grown on silicon. The chemical abruptness across the interface was investigated by atomic-resolution scanning transmission electron microscopy. The difference in the thermal expansion coefficients between LMO and Si imposed a large biaxial tensile strain to the LMO film, resulting in a tetragonal structure with c/a∼ 0.983. Consequently, we observed a significantly suppressed ferromagnetism along with an enhanced coercive field, as compared to the less distorted LMO film (c/a∼1.004) grown on STO single crystal. The results are discussed in terms of tensile-strain enhanced antiferromagnetic instabilities. Moreover, the ferromagnetism of LMO on Si sharply disappeared below a thickness of 5 unit cells, in agreement with the LMO/STO case, pointing to a robust critical behavior irrespective of the strain state. Our results demonstrate that the growth of oxide films on Si can be a promising way to study the tensile-strain effects in correlated oxides, and also pave the way towards the integration of multifunctional oxides on Si with atomic-layer control. |
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Place of Publication |
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Editor |
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Wos |
000513552900003 |
Publication Date |
2020-02-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.4 |
Times cited |
6 |
Open Access |
Not_Open_Access |
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Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Universiteit Antwerpen; Vlaamse regering; Fonds Wetenschappelijk Onderzoek, G093417N ; Javna Agencija za Raziskovalno Dejavnost RS, J2-9237 P2-0091 ; European Commission, H2020-ICT-2016-1-732642 ; |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
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Call Number |
EMAT @ emat @c:irua:167782 |
Serial |
6375 |
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| Permanent link to this record |
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Author |
Marchetti, A.; Saniz, R.; Krishnan, D.; Rabbachin, L.; Nuyts, G.; De Meyer, S.; Verbeeck, J.; Janssens, K.; Pelosi, C.; Lamoen, D.; Partoens, B.; De Wael, K. |
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Title |
Unraveling the Role of Lattice Substitutions on the Stabilization of the Intrinsically Unstable Pb2Sb2O7Pyrochlore: Explaining the Lightfastness of Lead Pyroantimonate Artists’ Pigments |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
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| |
Volume |
32 |
Issue |
7 |
Pages |
2863-2873 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
The pyroantimonate pigments Naples yellow and lead tin antimonate yellow are recognized as some of the most stable synthetic yellow pigments in the history of art. However, this exceptional lightfastness is in contrast with experimental evidence suggesting that this class of mixed oxides is of semiconducting nature. In this study the electronic structure and light-induced behavior of the lead pyroantimonate pigments were determined by means of a combined multifaceted analytical and computational approach (photoelectrochemical measurements, UV-vis diffuse reflectance spectroscopy, STEM-EDS, STEM-HAADF, and density functional theory calculations). The results demonstrate both the semiconducting nature and the lightfastness of these pigments. Poor optical absorption and minority carrier mobility are the main properties responsible for the observed stability. In addition, novel fundamental insights into the role played by Na atoms in the stabilization of the otherwise intrinsically unstable Pb2Sb2O7 pyrochlore were obtained. |
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Place of Publication |
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Wos |
000526394000016 |
Publication Date |
2020-04-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.6 |
Times cited |
8 |
Open Access |
OpenAccess |
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Notes |
Universiteit Antwerpen; Belgian Federal Science Policy Office; |
Approved |
Most recent IF: 8.6; 2020 IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:168819 |
Serial |
6363 |
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| Permanent link to this record |
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Author |
Keunecke, M.; Lyzwa, F.; Schwarzbach, D.; Roddatis, V.; Gauquelin, N.; Müller-Caspary, K.; Verbeeck, J.; Callori, S.J.; Klose, F.; Jungbauer, M.; Moshnyaga, V. |
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Title |
High-TCInterfacial Ferromagnetism in SrMnO3/LaMnO3Superlattices |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv. Funct. Mater. |
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Volume |
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Issue |
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Pages |
1808270 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Heterostructures of strongly correlated oxides demonstrate various intriguing and potentially useful interfacial phenomena. LaMnO3/SrMnO3 superlattices are presented showcasing a new high‐temperature ferromagnetic phase with Curie temperature, TC ≈360 K, caused by electron transfer from the surface of the LaMnO3 donor layer into the neighboring SrMnO3 acceptor layer. As a result, the SrMnO3 (top)/LaMnO3 (bottom) interface shows an enhancement of the magnetization as depth‐profiled by polarized neutron reflectometry. The length scale of charge transfer, λTF ≈2 unit cells, is obtained from in situ growth monitoring by optical ellipsometry, supported by optical simulations, and further confirmed by high resolution electron microscopy and spectroscopy. A model of the inhomogeneous distribution of electron density in LaMnO3/SrMnO3 layers along the growth direction is concluded to account for a complex interplay between ferromagnetic and antiferromagnetic layers in superlattices. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000535358900008 |
Publication Date |
2019-02-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1616301X |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
15.621 |
Times cited |
26 |
Open Access |
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Notes |
The authors thank EU FP7 Framework (Project IFOX) and DFG (SFB 1073, TP B04, A02, Z02) for the financial support. J.V., K.M.C and N.G. acknowledge funding through the GOA project “Solarpaint” of the University of Antwerp and from the FWO project G.0044.13N (Charge ordering). The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. The PNR experiment was funded by the Australian Nuclear Science and Technology Organization (proposal number P3985). |
Approved |
Most recent IF: NA |
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Call Number |
EMAT @ emat @UA @ admin @ c:irua:162108 |
Serial |
5294 |
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Author |
Prabhakara, V.; Jannis, D.; Béché, A.; Bender, H.; Verbeeck, J. |
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Title |
Strain measurement in semiconductor FinFET devices using a novel moiré demodulation technique |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Semiconductor science and technology |
Abbreviated Journal |
Semicond Sci Tech |
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Volume |
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Issue |
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Pages |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Moiré fringes are used throughout a wide variety of applications in physics and
engineering to bring out small variations in an underlying lattice by comparing with another reference lattice. This method was recently demonstrated in Scanning Transmission Electron Microscopy imaging to provide local strain measurement in crystals by comparing the crystal lattice with the scanning raster that then serves as the reference. The images obtained in this way contain a beating fringe pattern with a local period that represents the deviation of the lattice from the reference. In order to obtain the actual strain value, a region containing a full period of the fringe is required, which results in a compromise between strain sensitivity and spatial resolution. In this paper we propose an advanced setup making use of an optimised scanning pattern and a novel phase stepping demodulation scheme. We demonstrate the novel method on a series of 16 nm Si-Ge semiconductor FinFET devices in which strain plays a crucial role in modulating the charge carrier mobility. The obtained results are compared with both Nano-beam diffraction and the recently proposed Bessel beam diffraction technique. The setup provides a much improved spatial resolution over conventional moiré imaging in STEM while at the same time being fast and requiring no specialised diffraction camera as opposed to the diffraction techniques we compare to. |
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Wos |
000537721200002 |
Publication Date |
2019-11-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0268-1242 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.305 |
Times cited |
8 |
Open Access |
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Notes |
The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. We would also like to thank Dr. Thomas Nuytten and Prof. Dr. Wilfried Vandervorst from IMEC, Leuven for their continuous support and collaboration with the project. |
Approved |
Most recent IF: 2.305 |
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Call Number |
EMAT @ emat @c:irua:165794 |
Serial |
5445 |
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Author |
Velazco, A.; Nord, M.; Béché, A.; Verbeeck, J. |
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Title |
Evaluation of different rectangular scan strategies for STEM imaging |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
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Issue |
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Pages |
113021 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
STEM imaging is typically performed by raster scanning a focused electron probe over a sample. Here we investigate and compare three different scan patterns, making use of a programmable scan engine that allows to arbitrarily set the sequence of probe positions that are consecutively visited on the sample. We compare the typical raster scan with a so-called ‘snake’ pattern where the scan direction is reversed after each row and a novel Hilbert scan pattern that changes scan direction rapidly and provides an homogeneous treatment of both scan directions. We experimentally evaluate the imaging performance on a single crystal test sample by varying dwell time and evaluating behaviour with respect to sample drift. We demonstrate the ability of the Hilbert scan pattern to more faithfully represent the high frequency content of the image in the presence of sample drift. It is also shown that Hilbert scanning provides reduced bias when measuring lattice parameters from the obtained scanned images while maintaining similar precision in both scan directions which is especially important when e.g. performing strain analysis. Compared to raster scanning with flyback correction, both snake and Hilbert scanning benefit from dose reduction as only small probe movement steps occur. |
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Place of Publication |
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Language |
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Wos |
000544042800007 |
Publication Date |
2020-05-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.2 |
Times cited |
13 |
Open Access |
OpenAccess |
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Notes |
A.V., A.B. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. M.N. received support for this work from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 838001. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. |
Approved |
Most recent IF: 2.2; 2020 IF: 2.843 |
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Call Number |
EMAT @ emat @c:irua:169225 |
Serial |
6369 |
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Author |
Das, P.P.; Guzzinati, G.; Coll, C.; Gomez Perez, A.; Nicolopoulos, S.; Estrade, S.; Peiro, F.; Verbeeck, J.; Zompra, A.A.; Galanis, A.S. |
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Title |
Reliable Characterization of Organic & Pharmaceutical Compounds with High Resolution Monochromated EEL Spectroscopy |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Polymers |
Abbreviated Journal |
Polymers-Basel |
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Volume |
12 |
Issue |
7 |
Pages |
1434 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Organic and biological compounds (especially those related to the pharmaceutical industry) have always been of great interest for researchers due to their importance for the development of new drugs to diagnose, cure, treat or prevent disease. As many new API (active pharmaceutical ingredients) and their polymorphs are in nanocrystalline or in amorphous form blended with amorphous polymeric matrix (known as amorphous solid dispersion—ASD), their structural identification and characterization at nm scale with conventional X-Ray/Raman/IR techniques becomes difficult. During any API synthesis/production or in the formulated drug product, impurities must be identified and characterized. Electron energy loss spectroscopy (EELS) at high energy resolution by transmission electron microscope (TEM) is expected to be a promising technique to screen and identify the different (organic) compounds used in a typical pharmaceutical or biological system and to detect any impurities present, if any, during the synthesis or formulation process. In this work, we propose the use of monochromated TEM-EELS, to analyze selected peptides and organic compounds and their polymorphs. In order to validate EELS for fingerprinting (in low loss/optical region) and by further correlation with advanced DFT, simulations were utilized. |
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Place of Publication |
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Wos |
000556786700001 |
Publication Date |
2020-06-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2073-4360 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.364 |
Times cited |
6 |
Open Access |
OpenAccess |
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Notes |
C.C., F.P., S.E. acknowledges the Spanish government for projects MAT2016-79455-P, Research Network RED2018-102609-T and the FPI (BES-2017-080045) grant of Ministerio de Ciència, Innovación y Universidades. G.G. acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek—Vlaanderen (FWO). P.P.D., A.G.P., S.N. gratefully acknowledge much helpful discussion on EELS study for organic compounds with Dr. Andrey Chuvilin (CIC NANOGUNE, Donostia—San Sebastian, Spain). The authors also acknowledge Raúl Arenal (University de Zaragoza, Spain) for useful discussion on EELS. The authors acknowledge also Ulises Julio Amador Elizondo (Universidad CEU San Pablo, Spain) for kindly provide the aripiprazole and piroxicam samples for EELS study.; EUSMI_TA; |
Approved |
Most recent IF: NA |
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Call Number |
EMAT @ emat @c:irua:170603 |
Serial |
6400 |
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Author |
Do, M.T.; Gauquelin, N.; Nguyen, M.D.; Wang, J.; Verbeeck, J.; Blom, F.; Koster, G.; Houwman, E.P.; Rijnders, G. |
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Title |
Interfacial dielectric layer as an origin of polarization fatigue in ferroelectric capacitors |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Scientific Reports |
Abbreviated Journal |
Sci Rep-Uk |
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Volume |
10 |
Issue |
1 |
Pages |
7310 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Origins of polarization fatigue in ferroelectric capacitors under electric field cycling still remain unclear. Here, we experimentally identify origins of polarization fatigue in ferroelectric PbZr0.52Ti0.48O3 (PZT) thin-film capacitors by investigating their fatigue behaviours and interface structures. The PZT layers are epitaxially grown on SrRuO3-buffered SrTiO3 substrates by a pulsed laser deposition (PLD), and the capacitor top-electrodes are various, including SrRuO3 (SRO) made by in-situ PLD, Pt by in-situ PLD (Pt-inPLD) and ex-situ sputtering (Pt-sputtered). We found that fatigue behaviour of the capacitor is directly related to the top-electrode/PZT interface structure. The Pt-sputtered/PZT/SRO capacitor has a thin defective layer at the top interface and shows early fatigue while the Pt-inPLD/PZT/SRO and SRO/PZT/SRO capacitor have clean top-interfaces and show much more fatigue resistance. The defective dielectric layer at the Pt-sputtered/PZT interface mainly contains carbon contaminants, which form during the capacitor ex-situ fabrication. Removal of this dielectric layer significantly delays the fatigue onset. Our results clearly indicate that dielectric layer at ferroelectric capacitor interfaces is the main origin of polarization fatigue, as previously proposed in the charge injection model. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000559953800003 |
Publication Date |
2020-04-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
2045-2322 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4.6 |
Times cited |
18 |
Open Access |
OpenAccess |
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Notes |
; The authors acknowledge the financial support of the Nederlandse Organisatie voor Wetenschappelijk Onderzoek through Grant No. F62.3.15559. ; |
Approved |
Most recent IF: 4.6; 2020 IF: 4.259 |
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| |
Call Number |
EMAT @ emat @c:irua:169865 |
Serial |
6374 |
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| Permanent link to this record |
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Author |
Mehta, A.N.; Gauquelin, N.; Nord, M.; Orekhov, A.; Bender, H.; Cerbu, D.; Verbeeck, J.; Vandervorst, W. |
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| |
Title |
Unravelling stacking order in epitaxial bilayer MX₂ using 4D-STEM with unsupervised learning |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
|
| |
Volume |
31 |
Issue |
44 |
Pages |
445702 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
Following an extensive investigation of various monolayer transition metal dichalcogenides (MX2), research interest has expanded to include multilayer systems. In bilayer MX2, the stacking order strongly impacts the local band structure as it dictates the local confinement and symmetry. Determination of stacking order in multilayer MX(2)domains usually relies on prior knowledge of in-plane orientations of constituent layers. This is only feasible in case of growth resulting in well-defined triangular domains and not useful in-case of closed layers with hexagonal or irregularly shaped islands. Stacking order can be discerned in the reciprocal space by measuring changes in diffraction peak intensities. Advances in detector technology allow fast acquisition of high-quality four-dimensional datasets which can later be processed to extract useful information such as thickness, orientation, twist and strain. Here, we use 4D scanning transmission electron microscopy combined with multislice diffraction simulations to unravel stacking order in epitaxially grown bilayer MoS2. Machine learning based data segmentation is employed to obtain useful statistics on grain orientation of monolayer and stacking in bilayer MoS2. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000561424400001 |
Publication Date |
2020-07-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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| |
Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0957-4484 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
3.5 |
Times cited |
13 |
Open Access |
OpenAccess |
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Notes |
; J.V. acknowledges funding from FLAG-ERA JTC2017 project 'Graph-Eye'. N.G. acknowledges funding from GOA project 'Solarpaint' of the University of Antwerp. This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 823717-ESTEEM3. 4D STEM data was acquired on a hybrid pixel detector funded with a Hercules fund 'Direct electron detector for soft matter TEM' from the Flemish Government. M. N. acknowledges funding from a Marie Curie Fellowship agreement No 838001. We thank Dr Jiongjiong Mo and Dr Benjamin Groven for developing the CVD-MoS<INF>2</INF> growth on sapphire and providing the material used in this article. ; |
Approved |
Most recent IF: 3.5; 2020 IF: 3.44 |
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| |
Call Number |
UA @ admin @ c:irua:171119 |
Serial |
6649 |
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| Permanent link to this record |
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| |
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Author |
Bigiani, L.; Andreu, T.; Maccato, C.; Fois, E.; Gasparotto, A.; Sada, C.; Tabacchi, G.; Krishnan, D.; Verbeeck, J.; Ramon Morante, J.; Barreca, D. |
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Title |
Engineering Au/MnO₂ hierarchical nanoarchitectures for ethanol electrochemical valorization |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Materials Chemistry A |
Abbreviated Journal |
J Mater Chem A |
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| |
Volume |
8 |
Issue |
33 |
Pages |
16902-16907 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
The design of eco-friendly electrocatalysts for ethanol valorization is an open challenge towards sustainable hydrogen production. Herein we present an original fabrication route to effective electrocatalysts for the ethanol oxidation reaction (EOR). In particular, hierarchical MnO(2)nanostructures are grown on high-area nickel foam scaffolds by a plasma-assisted strategy and functionalized with low amounts of optimally dispersed Au nanoparticles. This strategy leads to catalysts with a unique morphology, designed to enhance reactant-surface contacts and maximize active site utilization. The developed nanoarchitectures show superior performances for ethanol oxidation in alkaline media. We reveal that Au decoration boosts MnO(2)catalytic activity by inducing pre-dissociation and pre-oxidation of the adsorbed ethanol molecules. This evidence validates our strategy as an effective route for the development of green electrocatalysts for efficient electrical-to-chemical energy conversion. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000562931300008 |
Publication Date |
2020-07-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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| |
ISSN |
2050-7488; 2050-7496 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
11.9 |
Times cited |
16 |
Open Access |
OpenAccess |
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Notes |
; This work was financially supported by Padova University DOR 2016-2019 and P-DiSC #03BIRD2018-UNIPD OXYGENA projects, as well as by the INSTM Consortium (INSTMPD004 – NETTUNO), AMGA Foundation Mn4Energy project and Insubria University FAR2018. J. V. and D. K. acknowledge funding from the Flemish Government (Hercules), GOA project “Solarpaint” (Antwerp University) and European Union's H2020 programme under grant agreement no. 823717 ESTEEM3. The authors are grateful to Dr Gianluca Corr for skillful technical support. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 11.9; 2020 IF: 8.867 |
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| |
Call Number |
UA @ admin @ c:irua:171989 |
Serial |
6506 |
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| Permanent link to this record |
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Author |
Van Dijck, J.G.; Mampuys, P.; Ching, H.Y.V.; Krishnan, D.; Baert, K.; Hauffman, T.; Verbeeck, J.; Van Doorslaer, S.; Maes, B.U.W.; Dorbec, M.; Buekenhoudt, A.; Meynen, V. |
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Title |
Synthesis – properties correlation and the unexpected role of the titania support on the Grignard surface modification |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Applied Surface Science |
Abbreviated Journal |
Appl Surf Sci |
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| |
Volume |
527 |
Issue |
|
Pages |
146851-17 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
While the impact of reaction conditions on surface modification with Grignard reactants has been studied for silica supports, such information is absent for metal oxides like titania. Differences between modified titania and silica are observed, making it paramount to explore the reaction mechanism. A detailed study on the impact of the reaction conditions is reported, with a focus on the chain length of the alkyl Grignard reactant, its concentration, the reaction time and temperature, and the type of titania support. While the increase in the chain length reduces the amount of organic groups on the surface, the concentration, time and temperature show little/no influence on the modification degree. However, the type of titania support used and the percentage of amorphous phase present has a significant impact on the amount of grafted groups. Even though the temperature and concentration show no clear impact on the modification degree, they can cause changes in the surface hydroxyl population, which are thus not linked to the modification degree. Furthermore, the titania support is reduced during functionalization. This reduction dependents on the reaction temperature, the titania support and the chain length of the Grignard reactant. Similarly, this reduction is not linked to the modification degree. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000564205300003 |
Publication Date |
2020-06-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0169-4332 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
6.7 |
Times cited |
5 |
Open Access |
OpenAccess |
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Notes |
; The FWO (Fonds Wetenschappelijk Onderzoek) is gratefully acknowledged for the VITO-FWO grant of fellow Jeroen G. Van Dijck (11W9416N) and the financial support granted in project GO12712N. The E.U. is acknowledged for H.Y. Vincent Ching's H2020-MSCA-IF (grant number 792946, iSPY). Dileep Krishnan and Johan Verbeeck acknowledge funding from GOA project “solarpaint” of the University of Antwerp. ; |
Approved |
Most recent IF: 6.7; 2020 IF: 3.387 |
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| |
Call Number |
UA @ admin @ c:irua:169722 |
Serial |
6712 |
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| Permanent link to this record |
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Author |
Jovanović, Z.; Gauquelin, N.; Koster, G.; Rubio-Zuazo, J.; Ghosez, P.; Verbeeck, J.; Suvorov, D.; Spreitzer, M. |
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Title |
Simultaneous heteroepitaxial growth of SrO (001) and SrO (111) during strontium-assisted deoxidation of the Si (001) surface |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Rsc Advances |
Abbreviated Journal |
Rsc Adv |
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| |
Volume |
10 |
Issue |
52 |
Pages |
31261-31270 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Epitaxial integration of transition-metal oxides with silicon brings a variety of functional properties to the well-established platform of electronic components. In this process, deoxidation and passivation of the silicon surface are one of the most important steps, which in our study were controlled by an ultra-thin layer of SrO and monitored by using transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), synchrotron X-ray diffraction (XRD) and reflection high energy electron diffraction (RHEED) methods. Results revealed that an insufficient amount of SrO leads to uneven deoxidation of the silicon surface<italic>i.e.</italic>formation of pits and islands, whereas the composition of the as-formed heterostructure gradually changes from strontium silicide at the interface with silicon, to strontium silicate and SrO in the topmost layer. Epitaxial ordering of SrO, occurring simultaneously with silicon deoxidation, was observed. RHEED analysis has identified that SrO is epitaxially aligned with the (001) Si substrate both with SrO (001) and SrO (111) out-of-plane directions. This observation was discussed from the point of view of SrO desorption, SrO-induced deoxidation of the Si (001) surface and other interfacial reactions as well as structural ordering of deposited SrO. Results of the study present an important milestone in understanding subsequent epitaxial integration of functional oxides with silicon using SrO. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000566579400025 |
Publication Date |
2020-08-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2046-2069 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.9 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
Vlaamse regering, Hercules Fund ; Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja, III 45006 ; Javna Agencija za Raziskovalno Dejavnost RS, J2-9237 P2-0091 ; Fonds Wetenschappelijk Onderzoek, G.0044.13N ; Ministerio de Ciencia, Innovación y Universidades; Universiteit Antwerpen, GOA project Solarpaint ; F.R.S.-FNRS, PDR project PROMOSPAN ; Consejo Superior de Investigaciones Cientificas; University of Liège, ARC project AIMED ; Ministry of Education, Science and Sport, M.ERA-NET project SIOX ; |
Approved |
Most recent IF: 3.9; 2020 IF: 3.108 |
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| |
Call Number |
EMAT @ emat @c:irua:172059 |
Serial |
6416 |
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| Permanent link to this record |
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Author |
Bigiani, L.; Gasparotto, A.; Maccato, C.; Sada, C.; Verbeeck, J.; Andreu, T.; Morante, J.R.; Barreca, D. |
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Title |
Dual improvement of beta-MnO₂ oxygen evolution electrocatalysts via combined substrate control and surface engineering |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Chemcatchem |
Abbreviated Journal |
Chemcatchem |
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Volume |
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Issue |
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Pages |
1-10 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The development of catalysts with high intrinsic activity towards the oxygen evolution reaction (OER) plays a critical role in sustainable energy conversion and storage. Herein, we report on the development of efficient (photo)electrocatalysts based on functionalized MnO(2)systems. Specifically,beta-MnO(2)nanostructures grown by plasma enhanced-chemical vapor deposition on fluorine-doped tin oxide (FTO) or Ni foams were decorated with Co(3)O(4)or Fe(2)O(3)nanoparticles by radio frequency sputtering. Upon functionalization, FTO-supported materials yielded a performance increase with respect to bare MnO2, with current densities at 1.65 Vvs. the reversible hydrogen electrode (RHE) up to 3.0 and 3.5 mA/cm(2)in the dark and under simulated sunlight, respectively. On the other hand, the use of highly porous and conductive Ni foam substrates enabled to maximize cooperative interfacial effects between catalyst components. The best performing Fe2O3/MnO(2)system provided a current density of 17.9 mA/cm(2)at 1.65 Vvs. RHE, an overpotential as low as 390 mV, and a Tafel slope of 69 mV/decade under dark conditions, comparing favorably with IrO(2)and RuO(2)benchmarks. Overall, the control of beta-MnO2/substrate interactions and the simultaneous surface property engineering pave the way to an efficient energy generation from abundant natural resources. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000571229000001 |
Publication Date |
2020-09-18 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
1867-3880; 1867-3899 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.5 |
Times cited |
5 |
Open Access |
Not_Open_Access |
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Notes |
; This work has been financially supported by Padova University DOR 2017-2019, P-DiSC #03BIRD2016-UNIPD and #03BIRD2018-UNIPD projects. A.G. acknowledges AMGA Foundation and INSTM Consortium. J.V. gratefully acknowledges funding from the GOA project “Solarpaint” of the University of Antwerp and the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717-ESTEEM3. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 4.5; 2020 IF: 4.803 |
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Call Number |
UA @ admin @ c:irua:171949 |
Serial |
6493 |
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| Permanent link to this record |
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Author |
Bigiani, L.; Gasparotto, A.; Andreu, T.; Verbeeck, J.; Sada, C.; Modin, E.; Lebedev, O.I.; Morante, J.R.; Barreca, D.; Maccato, C. |
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Title |
Au-manganese oxide nanostructures by a plasma-assisted process as electrocatalysts for oxygen evolution : a chemico-physical investigation |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Advanced sustainable systems |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
2000177-11 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Earth-abundant and eco-friendly manganese oxides are promising platforms for the oxygen evolution reaction (OER) in water electrolysis. Herein, a versatile and potentially scalable route to gold-decorated manganese oxide-based OER electrocatalysts is reported. In particular, MnxOy(MnO2, Mn2O3) host matrices are grown on conductive glasses by plasma assisted-chemical vapor deposition (PA-CVD), and subsequently functionalized with gold nanoparticles (guest) as OER activators by radio frequency (RF)-sputtering. The final selective obtainment of MnO2- or Mn2O3-based systems is then enabled by annealing under oxidizing or inert atmosphere, respectively. A detailed material characterization evidences the formation of high-purity Mn(x)O(y)dendritic nanostructures with an open morphology and an efficient guest dispersion into the host matrices. The tailoring of Mn(x)O(y)phase composition and host-guest interactions has a remarkable influence on OER activity yielding, for the best performing Au/Mn(2)O(3)system, a current density of approximate to 5 mA cm(-2)at 1.65 V versus the reversible hydrogen electrode (RHE) and an overpotential close to 300 mV at 1 mA cm(-2). Such results, comparing favorably with literature data on manganese oxide-based materials, highlight the importance of compositional control, as well as of surface and interface engineering, to develop low-cost and efficient anode nanocatalysts for water splitting applications. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000572376000001 |
Publication Date |
2020-09-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
2366-7486 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.1 |
Times cited |
4 |
Open Access |
Not_Open_Access |
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Notes |
; Padova University (DOR 2017-2019 and P-DiSC #03BIRD2018-UNIPD OXYGENA projects), as well as the INSTM Consortium (INSTMPD004 – NETTUNO project) and AMGA Foundation (Mn4Energy project), are gratefully acknowledged for financial support. The Qu-Ant-EM microscope was partially funded by the Hercules fund from the Flemish Government. J.V. acknowledges funding from a GOA project “Solarpaint” from the University of Antwerp and from EU H2020 823717 ESTEEM3 project. The authors thank Dr. Daniele Valbusa, Dr. Gianluca Corr, Dr. Andrea Gallo, and Dr. Dileep Khrishnan for helpful experimental assistance. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 7.1; 2020 IF: NA |
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Call Number |
UA @ admin @ c:irua:171937 |
Serial |
6457 |
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| Permanent link to this record |
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Author |
Wang, J.; Gauquelin, N.; Huijben, M.; Verbeeck, J.; Rijnders, G.; Koster, G. |
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Title |
Metal-insulator transition of SrVO 3 ultrathin films embedded in SrVO 3 / SrTiO 3 superlattices |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl Phys Lett |
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Volume |
117 |
Issue |
13 |
Pages |
133105 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The metal-insulator transition (MIT) in strongly correlated oxides is a topic of great interest for its potential applications, such as Mott field effect transistors and sensors. We report that the MIT in high quality epitaxial SrVO3 (SVO) thin films is present as the film thickness is reduced, lowering the dimensionality of the system, and electron-electron correlations start to become the dominant interactions. The critical thickness of 3 u.c is achieved by avoiding effects due to off-stoichiometry using optimal growth conditions and excluding any surface effects by a STO capping layer. Compared to the single SVO thin films, conductivity enhancement in SVO/STO superlattices is observed. This can be explained by the interlayer coupling effect between SVO sublayers in the superlattices. Magnetoresistance and Hall measurements indicate that the dominant driving force of MIT is the electron–electron interaction. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000577126100001 |
Publication Date |
2020-09-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-6951 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4 |
Times cited |
8 |
Open Access |
OpenAccess |
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Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek, 13HTSM01 ; |
Approved |
Most recent IF: 4; 2020 IF: 3.411 |
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Call Number |
EMAT @ emat @c:irua:172461 |
Serial |
6415 |
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| Permanent link to this record |
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Author |
Chen, B.; Gauquelin, N.; Jannis, D.; Cunha, D.M.; Halisdemir, U.; Piamonteze, C.; Lee, J.H.; Belhadi, J.; Eltes, F.; Abel, S.; Jovanovic, Z.; Spreitzer, M.; Fompeyrine, J.; Verbeeck, J.; Bibes, M.; Huijben, M.; Rijnders, G.; Koster, G. |
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Title |
Strain-engineered metal-to-insulator transition and orbital polarization in nickelate superlattices integrated on silicon |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Advanced Materials |
Abbreviated Journal |
Adv Mater |
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Volume |
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Issue |
|
Pages |
2004995 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Epitaxial growth of SrTiO3 (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO3/LaFeO3 SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy. Both sets of SLs show a similar thickness-driven metal-to-insulator transition, albeit with resistivity and transition temperature modified by the different amounts of strain. In particular, the large tensile strain promotes a pronounced Ni 3dx2-y2 orbital polarization for the SL grown on Si/STO, comparable to that reported for LaNiO3 SL epitaxially strained to DyScO3 substrate. Those results illustrate the ability to integrate oxide SLs on silicon with structure and property approaching their counterparts grown on STO single crystal, and also open up new prospects of strain engineering in functional oxides based on the Si platform. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000588146500001 |
Publication Date |
2020-11-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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| |
ISSN |
0935-9648 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
29.4 |
Times cited |
18 |
Open Access |
OpenAccess |
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Notes |
; This work is supported by the international M-ERA.NET project SIOX (project 4288) and H2020 project ULPEC (project 732642). M.S. acknowledges funding from Slovenian Research Agency (Grants No. J2-9237 and No. P2-0091). This work received support from the ERC CoG MINT (#615759) and from a PHC Van Gogh grant. M.B. thanks the French Academy of Science and the Royal Netherlands Academy of Arts and Sciences for supporting his stays in the Netherlands. This project has received funding as a transnational access project from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. N.G. and J.V. acknowledge GOA project “Solarpaint” of the University of Antwerp. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 29.4; 2020 IF: 19.791 |
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| |
Call Number |
UA @ admin @ c:irua:173516 |
Serial |
6617 |
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| Permanent link to this record |
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Author |
Lebedev, N.; Stehno, M.; Rana, A.; Gauquelin, N.; Verbeeck, J.; Brinkman, A.; Aarts, J. |
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Title |
Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO₃/SrTiO₃ interfaces |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
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Volume |
33 |
Issue |
5 |
Pages |
055001 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We have studied the transport properties of LaTiO3/SrTiO3 (LTO/STO) heterostructures. In spite of 2D growth observed in reflection high energy electron diffraction, transmission electron microscopy images revealed that the samples tend to amorphize. Still, we observe that the structures are conducting, and some of them exhibit high conductance and/or superconductivity. We established that conductivity arises mainly on the STO side of the interface, and shows all the signs of the two-dimensional electron gas usually observed at interfaces between STO and LTO or LaAlO3, including the presence of two electron bands and tunability with a gate voltage. Analysis of magnetoresistance (MR) and superconductivity indicates the presence of spatial fluctuations of the electronic properties in our samples. That can explain the observed quasilinear out-of-plane MR, as well as various features of the in-plane MR and the observed superconductivity. |
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Wos |
000588209300001 |
Publication Date |
2020-10-14 |
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Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
; NL and JA gratefully acknowledge the financial support of the research program DESCO, which is financed by the Netherlands Organisation for Scientific Research (NWO). The authors thank J Jobst, S Smink, K Lahabi and G Koster for useful discussion. ; |
Approved |
Most recent IF: 2.7; 2020 IF: 2.649 |
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Call Number |
UA @ admin @ c:irua:173679 |
Serial |
6545 |
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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. |
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Title |
Single femtosecond laser pulse excitation of individual cobalt nanoparticles |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
102 |
Issue |
20 |
Pages |
205418 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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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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Wos |
000589602000005 |
Publication Date |
2020-11-16 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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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 |
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Call Number |
EMAT @ emat @c:irua:174273 |
Serial |
6669 |
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Author |
Lin, S.-C.; Kuo, C.-T.; Shao, Y.-C.; Chuang, Y.-D.; Geessinck, J.; Huijben, M.; Rueff, J.-P.; Graff, I.L.; Conti, G.; Peng, Y.; Bostwick, A.; Gullikson, E.; Nemsak, S.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Ghiringhelli, G.; Schneider, C.M.; Fadley, C.S. |
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Title |
Two-dimensional electron systems in perovskite oxide heterostructures : role of the polarity-induced substitutional defects |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
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Volume |
4 |
Issue |
11 |
Pages |
115002 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The discovery of a two-dimensional electron system (2DES) at the interfaces of perovskite oxides such as LaAlO3 and SrTiO3 has motivated enormous efforts in engineering interfacial functionalities with this type of oxide heterostructures. However, the fundamental origins of the 2DES are still not understood, e.g., the microscopic mechanisms of coexisting interface conductivity and magnetism. Here we report a comprehensive spectroscopic investigation on the depth profile of 2DES-relevant Ti 3d interface carriers using depthand element-specific techniques like standing-wave excited photoemission and resonant inelastic scattering. We found that one type of Ti 3d interface carriers, which give rise to the 2DES are located within three unit cells from the n-type interface in the SrTiO3 layer. Unexpectedly, another type of interface carriers, which are polarity-induced Ti-on-Al antisite defects, reside in the first three unit cells of the opposing LaAlO3 layer (similar to 10 angstrom). Our findings provide a microscopic picture of how the localized and mobile Ti 3d interface carriers distribute across the interface and suggest that the 2DES and 2D magnetism at the LaAlO3/SrTiO3 interface have disparate explanations as originating from different types of interface carriers. |
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Wos |
000592432200004 |
Publication Date |
2020-11-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2475-9953 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.4 |
Times cited |
7 |
Open Access |
OpenAccess |
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Notes |
; We thank G. M. De Luca and L. Braicovich for discussions. Charles S. Fadley was deceased on August 1, 2019. We are grateful for his significant contributions to this work. We thank Advanced Light Source for the access to Beamline 8.0.3 (qRIXS) via Proposal No. 09892 and beamline 7.0.2 (MAESTRO) via Proposal No. RA-00291 that contributed to the results presented here. We thank synchrotron SOLEIL (via Proposal No. 99180118) for the access to Beamline GALAXIES. This work was supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231 (Advanced Light Source), and by DOE Contract No. DE-SC0014697 through the University of California, Davis (S.-C.L., C.-T.K, and C.S.F.), and from the Julich Research Center, Peter Grunberg Institute, PGI-6. I. L. G. wishes to thank Brazilian scientific agencies CNPQ (Project No. 200789/2017-1) and CAPES (CAPES-PrInt-UFPR) for their financial support. J.V. and N.G. acknowledge funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and the European Union's horizon 2020 research and innovation program ES-TEEM3 under grant agreement no 823717. The Qu-Ant-EM microscope used in this study was partly funded by the Hercules fund from the Flemish Government. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
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Call Number |
UA @ admin @ c:irua:174316 |
Serial |
6713 |
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Author |
Fatermans, J.; den Dekker, Aj.; Müller-Caspary, K.; Gauquelin, N.; Verbeeck, J.; Van Aert, S. |
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Title |
Atom column detection from simultaneously acquired ABF and ADF STEM images |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
219 |
Issue |
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Pages |
113046 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
In electron microscopy, the maximum a posteriori (MAP) probability rule has been introduced as a tool to determine the most probable atomic structure from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images exhibiting low contrast-to-noise ratio (CNR). Besides ADF imaging, STEM can also be applied in the annular bright-field (ABF) regime. The ABF STEM mode allows to directly visualize light-element atomic columns in the presence of heavy columns. Typically, light-element nanomaterials are sensitive to the electron beam, limiting the incoming electron dose in order to avoid beam damage and leading to images exhibiting low CNR. Therefore, it is of interest to apply the MAP probability rule not only to ADF STEM images, but to ABF STEM images as well. In this work, the methodology of the MAP rule, which combines statistical parameter estimation theory and model-order selection, is extended to be applied to simultaneously acquired ABF and ADF STEM images. For this, an extension of the commonly used parametric models in STEM is proposed. Hereby, the effect of specimen tilt has been taken into account, since small tilts from the crystal zone axis affect, especially, ABF STEM intensities. Using simulations as well as experimental data, it is shown that the proposed methodology can be successfully used to detect light elements in the presence of heavy elements. |
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Place of Publication |
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Language |
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Wos |
000594768500005 |
Publication Date |
2020-06-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.2 |
Times cited |
9 |
Open Access |
OpenAccess |
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Notes |
The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (No. W.O.010.16N, No. G.0368.15N, No. G.0502.18N, EOS 30489208). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 823717 – ESTEEM3. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. K. M. C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association (Germany) under contract VH-NG-1317. The authors thank Mark Huijben from the University of Twente (Enschede, The Netherlands) for providing the LiMn2O4 sample used in section 4.2 of this study. N. G., J. V., and S. V. A. acknowledge funding from the University of Antwerp through the Concerted Research Actions (GOA) project Solarpaint and the TOP project. |
Approved |
Most recent IF: 2.2; 2020 IF: 2.843 |
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Call Number |
EMAT @ emat @c:irua:169706 |
Serial |
6373 |
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