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“Nonmonotonic field dependence of damping and reappearance of Rabi oscillations in quantum dots”. Vagov A, Croitoru MD, Axt VM, Kuhn T, Peeters FM, Physical review letters 98, 1 (2007). http://doi.org/10.1103/PhysRevLett.98.227403
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 8.462
Times cited: 91
DOI: 10.1103/PhysRevLett.98.227403
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“On the crystal structure of TiNi-Cu martensite”. Potapov P, Shelyakov A, Schryvers D, Scripta materialia 44, 1 (2001). http://doi.org/10.1016/S1359-6462(00)00555-8
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.747
Times cited: 36
DOI: 10.1016/S1359-6462(00)00555-8
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“Oxygen exchange on nanocrystalline tin dioxide modified by palladium”. Frolov DD, Kotovshchikov YN, Morozov IV, Boltalin AI, Fedorova AA, Marikutsa AV, Rumyantseva MN, Gaskov AM, Sadovskaya EM, Abakumov AM, Journal of solid state chemistry 186, 1 (2012). http://doi.org/10.1016/j.jssc.2011.11.028
Abstract: Temperature-programmed oxygen isotopic exchange study was performed on nanocrystalline tin dioxide-based materials synthesized via sol-gel route and modified by palladium. Such materials are widely used as resistive gas sensors. The experiments were carried out in a flow-reactor up to complete isotopic substitution of oxygen. Substantial rates of isotopic exchange for SnO2 were observed from about 700 K. The distribution of isotopic molecules O-16(2). (OO)-O-16-O-18 and O-18(2) corresponds to simple dioxygen heteroexchange mechanism with single lattice oxygen atom. The modification of SnO2 by Pd introduced multiple heteroexchange mechanism with preliminary O-2 dissociation on the clusters surface. Spill-over of atomic oxygen from Pd to the surface of SnO2 and fast exchange with lattice oxygen result in more than 100% increase of apparent heteroexchange rate. The exchange on SnO2/Pd was shown to be a complex process involving partial deactivation of the catalytic centers at temperature higher than 750 K. (C) 2011 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 34
DOI: 10.1016/j.jssc.2011.11.028
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“Production of short carbon nanotubes with open tips by ball milling”. Pierard N, Fonseca A, Konya Z, Willems I, Van Tendeloo G, Nagy JB, Chemical physics letters 335, 1 (2001). http://doi.org/10.1016/S0009-2614(01)00004-5
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.815
Times cited: 203
DOI: 10.1016/S0009-2614(01)00004-5
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“Quantitative electron tomography : the effect of the three-dimensional point spread function”. Heidari H, van den Broek W, Bals S, Ultramicroscopy 135, 1 (2013). http://doi.org/10.1016/j.ultramic.2013.06.005
Abstract: The intensity levels in a three-dimensional (3D) reconstruction, obtained by electron tomography, can be influenced by several experimental imperfections. Such artifacts will hamper a quantitative interpretation of the results. In this paper, we will correct for artificial intensity variations by determining the 3D point spread function (PSF) of a tomographic reconstruction based on high angle annular dark field scanning transmission electron microscopy. The large tails of the PSF cause an underestimation of the intensity of smaller particles, which in turn hampers an accurate radius estimate. Here, the error introduced by the PSF is quantified and corrected a posteriori.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 6
DOI: 10.1016/j.ultramic.2013.06.005
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“Statistical experimental design for quantitative atomic resolution transmission electron microscopy”. Van Aert S, den Dekker AJ, van den Bos A, van Dyck D Academic Press, San Diego, Calif., page 1 (2004).
Keywords: H1 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
Times cited: 13
DOI: 10.1016/S1076-5670(04)30001-7
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“Structural phase transformations in alloys: an electron microscopy study”. Van Tendeloo G, Schryvers D, Tanner LE, Broddin D, Ricolleau C, Loiseau A, Symposium on Pahse Transformations , 1 (1991)
Keywords: P3 Proceeding; Electron microscopy for materials research (EMAT)
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“Superconducting ceramics”. de Hosson JTM, Van Tendeloo G Vch, Weinheim, page 1 (1997).
Keywords: H3 Book chapter; Electron microscopy for materials research (EMAT)
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“Superconductivity up to 110K in the 1212-Hg based cuprate Nd1-xCaxBa2Hg1-xCu2+xO6+y”. Maignan A, Michel C, Van Tendeloo G, Hervieu M, Raveau B, Physica: C : superconductivity 216, 1 (1993)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.942
Times cited: 32
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“Tailoring CuO nanostructures for enhanced photocatalytic property”. Liu J, Jin J, Deng Z, Huang SZ, Hu ZY, Wang L, Wang C, Chen LH, Li Y, Van Tendeloo G, Su BL;, Journal of colloid and interface science 384, 1 (2012). http://doi.org/10.1016/j.jcis.2012.06.044
Abstract: We report on one-pot synthesis of various morphologies of CuO nanostructures. PEG200 as a structure directing reagent under the synergism of alkalinity by hydrothermal method has been employed to tailor the morphology of CuO nanostructures. The CuO products have been characterized by XRD, SEM, and TEM. The morphologies of the CuO nanostructures can be tuned from 10 (nanoseeds, nanoribbons) to 2D (nanoleaves) and to 3D (shuttle-like, shrimp-like, and nanoflowers) by changing the volume of PEG200 and the alkalinity in the reaction system. At neutral and relatively low alkalinity (OH-/Cu2+ <= 3), the addition of PEG200 can strongly influence the morphologies of the CuO nanostructures. At high alkalinity (OH/Cu2+ >= 4), PEG200 has no influence on the morphology of the CuO nanostructure. The different morphologies of the CuO nanostructures have been used for the photodecomposition of the pollutant rhodamine B (RhB) in water. The photocatalytic activity has been correlated with the different nanostructures of CuO. The 10 CuO nanoribbons exhibit the best performance on the RhB photodecomposition because of the exposed high surface energy {-121} crystal plane. The photocatalytic results show that the high energy surface planes of the CuO nanostructures mostly affect the photocatalytic activity rather than the morphology of the CuO nanostructures. Our synthesis method also shows it is possible to control the morphologies of nanostructures in a simple way. (C) 2012 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.233
Times cited: 105
DOI: 10.1016/j.jcis.2012.06.044
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“Tuning the superconducting properties of nanomaterials”. Croitoru MD, Shanenko AA, Peeters FM Springer, Dordrecht, page 1 (2009).
Abstract: Electron continement and its effect on the superconducting-to-normal phase transition driven by a magentic field and/or a current is studied in nanowires. Our investigation is based on a self-consistent numerical solution of the Bogoliubov-de Gennes equations. We find that in a parallel magneitc field and/or in the presence of a supercurrent the transition from the superconducting to the normal phase occurs as a cascade of discontinuous jumps in the superconducting order parameter for diameters D < 10 divided by 15 nm at T = 0. The critical magentic field exhibits quantum-size oscillations with pronounced resonant enhancements as a function of the wire radius.
Keywords: H1 Book chapter; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
DOI: 10.1007/978-90-481-3120-4_1
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“Reduced Anisotropy and Enhanced In-Field Performance of Thick BaHfO3-Doped Films on ABAD-YSZ Templates”. Pahlke P, Lao M, Eisterer M, Meledin A, Van Tendeloo G, Hanisch J, Sieger M, Usoskin A, Stromer J, Holzapfel B, Schultz L, Huhne R, IEEE transactions on applied superconductivity 26, 1 (2016). http://doi.org/10.1109/TASC.2016.2541998
Abstract: Pure and 6 mol% BaHfO3 (BHO) doped YBa2Cu3O7-δ (YBCO) films were prepared on CeO2-buffered ABAD-YSZ templates by pulsed laser deposition. The self-field Jc at 77 K reaches 1.1 MA/cm² in the doped sample compared to 2.5 MA/cm² in pure YBCO, at a film thickness of around 1 μm. Above a magnetic field of 2.2 T along B||c, Jc of the BHO-doped sample exceeds the Jc of the undoped film. The maximum pinning force density (FP,max) reaches a value of around 3 GN/cm² for both samples, but B(FP,max) increases from 1.4 T (pure) to a value of 2.9 T (BHO:YBCO). The Jc anisotropy curves of the doped sample show a large and broad peak at B||c and a strongly reduced anisotropy at all temperatures and fields compared to the pure sample. A complex defect structure with YBa2Cu4O8 intergrowths, Y2O3 precipitates and BHO nanocolumns with a fanshaped structure is observed by TEM investigations, which can explain the measured Jc(B,θ) behavior.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 14
DOI: 10.1109/TASC.2016.2541998
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“Ba2Y(Nb/Ta)O6–Doped YBCO Films on Biaxially Textured Ni–5at.% W Substrates”. Sieger M, Pahlke P, Hanisch J, Sparing M, Bianchetti M, MacManus-Driscoll J, Lao M, Eisterer M, Meledin A, Van Tendeloo G, Nast R, Schultz L, Holzapfel B, Huhne R, IEEE transactions on applied superconductivity 26, 1 (2016). http://doi.org/10.1109/TASC.2016.2539254
Abstract: The incorporation of nanoscaled pinning centers in superconducting YBa2Cu3O7-d (YBCO) films is one of the core topics to enhance the critical current density Jc(B, Q) of coated conductors. The mixed double-perovskite Ba2Y(Nb/Ta)O6 (BYNTO) can be grown in nanosized columns parallel the YBCO c-axis and in step-like patterns, making it customizable to meet specific working conditions (T, B, Q). We compare a 1.6 μm thick film of pure YBCO and a similar film with additional 5 mol% of BYNTO, grown by pulsed laser deposition with a growth rate of 1.6 nm/s on buffered biaxially textured Ni-5at.% W tape. Our doped sample shows nanosized BYNTO columns parallel cYBCO and plates in the ab-plane containing Y, Nb and Ta. An improved homogeneity of the critical current density Jc over the sample was evaluated from trapped field profiles measured with a scanning Hall probe microscope. The mean Jc in rolling direction of the tape is 1.8 MA/cm² (77 K, self-field) and doubles the value of the undoped sample. Angular dependent measurements of the critical current density, Jc(Q), show a decreased anisotropy of the doped film for various magnetic fields at 77 K as well as 64 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 6
DOI: 10.1109/TASC.2016.2539254
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“Measuring the height-to-height correlation function of corrugation in suspended graphene”. Kirilenko DA, Brunkov PN, Ultramicroscopy 165, 1 (2016). http://doi.org/10.1016/j.ultramic.2016.03.010
Abstract: Nanocorrugation of 2D crystals is an important phenomenon since it affects their electronic and mechanical properties. The corrugation may have various sources; one of them is flexural phonons that, in particular, are responsible for the thermal conductivity of graphene. A study of corrugation of just the suspended graphene can reveal much of valuable information on the physics of this complicated phenomenon. At the same time, the suspended crystal nanorelief can hardly be measured directly because of high flexibility of the 2D crystal. Moreover, the relief portion related to rapid out-of-plane oscillations (flexural phonons) is also inaccessible by such measurements. Here we present a technique for measuring the Fourier components of the height-height correlation function H(q) of suspended graphene which includes the effect of flexural phonons. The technique is based on the analysis of electron diffraction patterns. The H(q) is measured in the range of wavevectors q approximately 0.4-4.5nm(-1). At the upper limit of this range H(q) does follow the T/kappaq(4) law. So, we measured the value of suspended graphene bending rigidity kappa=1.2+/-0.4eV at ambient temperature T approximately 300K. At intermediate wave vectors, H(q) follows a slightly weaker exponent than theoretically predicted q(-3.15) but is closer to the results of the molecular dynamics simulation. At low wave vectors, the dependence becomes even weaker, which may be a sign of influence of charge carriers on the dynamics of undulations longer than 10nm. The technique presented can be used for studying physics of flexural phonons in other 2D materials.
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 2.843
Times cited: 3
DOI: 10.1016/j.ultramic.2016.03.010
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“Engineering properties by long range symmetry propagation initiated at perovskite heterostructure interface”. Liao ZL, Green RJ, Gauquelin N, Gonnissen J, Van Aert S, Verbeeck J, et al, Advanced functional materials , 1 (2016)
Abstract: In epitaxial thin film systems, the crystal structure and its symmetry deviate from the bulk counterpart due to various mechanisms such as epitaxial strain and interfacial structural coupling, which induce an accompanying change in their properties. In perovskite materials, the crystal symmetry can be described by rotations of 6-fold coordinated transition metal oxygen octahedra, which are found to be altered at interfaces. Here, we unravel how the local oxygen octahedral coupling (OOC) at perovskite heterostructural interfaces initiates a different symmetry in epitaxial films and provide design rules to induce various symmetries in thin films by careful selecting appropriate combinations of substrate/buffer/film. Very interestingly we discovered that these combinations lead to symmetry changes throughout the full thickness of the film. Our results provide a deep insight into understanding the origin of induced crystal symmetry in a perovskite heterostructure and an intelligent route to achieve unique functional properties.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
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“Influence of substrate tilt angle on the incorporation of BaHfO3 in thick YBa2Cu3O7-&delta, films”. Sieger M, Pahlke P, Ottolinger R, Stafford BH, Lao M, Meledin A, Bauer M, Eisterer M, Van Tendeloo G, Schultz L, Nielsch K, Hühne R, IEEE transactions on applied superconductivity 27, 1 (2016). http://doi.org/10.1109/Tasc.2016.2631587
Abstract: High critical current densities can be realized in high-temperature superconductors such as YBa2Cu3O7-δ (YBCO) by controlling density, shape, size and direction of a secondary phase. Whereas the dependence on the growth rate and deposition temperature has been widely studied as key parameters for nano-engineering the pinning landscape, the vicinal tilt of the substrate surface might have an additional influence. Therefore, we deposited 6 mol% BaHfO3 (BHO) doped YBCO on SrTiO3 (STO) substrates with vicinal angles α between 0° and 40° to identify the influence of the tilt on the growth mode of BHO. An undisturbed epitaxial growth of the superconductor as well as an epitaxial integration of the BHO phase in the YBCO matrix is observed for all vicinal angles investigated. The critical temperature is constant up to α = 20°, whereas the self-field critical current density at 77 K starts to decrease above 10°. A detailed structural analysis of the film cross sections showed that the growth mode of BHO changes already for a vicinal tilt of 2° from a pure c-axis oriented growth to a layered structure with BHO aligned parallel to the YBCO ab-plane. We identified a strong influence of such a microstructure on the current flow in BHO doped YBCO films on STO substrates as well as on MgO based coated conductors prepared by inclined substrate deposition
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 3
DOI: 10.1109/Tasc.2016.2631587
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“Theory and applications of free-electron vortex states”. Bliokh KY, Ivanov IP, Guzzinati G, Clark L, Van Boxem R, Béché, A, Juchtmans R, Alonso MA, Schattschneider P, Nori F, Verbeeck J, Physics reports 690, 1 (2017). http://doi.org/10.1016/j.physrep.2017.05.006
Abstract: Both classical and quantum waves can form vortices: with helical phase fronts and azimuthal current densities. These features determine the intrinsic orbital angular momentum carried by localized vortex states. In the past 25 years, optical vortex beams have become an inherent part of modern optics, with many remarkable achievements and applications. In the past decade, it has been realized and demonstrated that such vortex beams or wavepackets can also appear in free electron waves, in particular, in electron microscopy. Interest in free-electron vortex states quickly spread over different areas of physics: from basic aspects of quantum mechanics, via applications for fine probing of matter (including individual atoms), to high-energy particle collision and radiation processes. Here we provide a comprehensive review of theoretical and experimental studies in this emerging field of research. We describe the main properties of electron vortex states, experimental achievements and possible applications within transmission electron microscopy, as well as the possible role of vortex electrons in relativistic and high-energy processes. We aim to provide a balanced description including a pedagogical introduction, solid theoretical basis, and a wide range of practical details. Special attention is paid to translate theoretical insights into suggestions for future experiments, in electron microscopy and beyond, in any situation where free electrons occur.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 17.425
Times cited: 210
DOI: 10.1016/j.physrep.2017.05.006
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“Ship-in-a-bottle CMPO in MIL-101(Cr) for selective uranium recovery from aqueous streams through adsorption”. De Decker J, Folens K, De Clercq J, Meledina M, Van Tendeloo G, Du Laing G, Van Der Voort P, Journal of hazardous materials 335, 1 (2017). http://doi.org/10.1016/J.JHAZMAT.2017.04.029
Abstract: Mesoporous MIL-101(Cr) is used as host for a ship-in-a-bottle type adsorbent for selective U(VI) recovery from aqueous environments. The acid-resistant cage-type MOF is built in-situ around N,N-Diisobutyl-2-(octylphenylphosphoryl)acetamide (CMPO), a sterically demanding ligand with high U(VI) affinity. This one-step procedure yields an adsorbent which is an ideal compromise between homogeneous and heterogeneous systems, where the ligand can act freely within the pores of MIL-101, without leaching, while the adsorbent is easy separable and reusable. The adsorbent was characterized by XRD, FTIR spectroscopy, nitrogen adsorption, XRF, ADF-STEM and EDX, to confirm and quantify the successful encapsulation of the CMPO in MIL-101, and the preservation of the host. Adsorption experiments with a central focus on U(VI) recovery were performed. Very high selectivity for U(VI) was observed, while competitive metal adsorption (rare earths, transition metals...) was almost negligible. The adsorption capacity was calculated at 5.32 mg U/g (pH 3) and 27.99 mg U/g (pH 4), by fitting equilibrium data to the Langmuir model. Adsorption kinetics correlated to the pseudo-second-order model, where more than 95% of maximum uptake is achieved within 375 min. The adsorbed U(VI) is easily recovered by desorption in 0.1 M HNO3. Three adsorption/desorption cycles were performed. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.065
Times cited: 35
DOI: 10.1016/J.JHAZMAT.2017.04.029
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“The reduction of the substitutional C content in annealed Si/SiGeC superlattices studied by dark-field electron holography”. Denneulin T, Rouvière JL, Béché, A, Py M, Barnes JP, Rochat N, Hartmann JM, Cooper D, Semiconductor science and technology 26, 1 (2011). http://doi.org/10.1088/0268-1242/26/12/125010
Abstract: Si/Si(1 − x − y)GexCy superlattices are used in the construction of new microelectronic architectures such as multichannel transistors. The introduction of carbon in SiGe allows for compensation of the strain and to avoid plastic relaxation. However, the formation of incoherent β-SiC clusters during annealing limits the processability of SiGeC. This precipitation leads to a modification of the strain in the alloy due to the reduction of the substitutional carbon content. Here, we investigated the strain in annealed Si/Si0.744Ge0.244C0.012 superlattices grown by reduced pressure chemical vapour deposition using dark-field electron holography. The variation of the substitutional C content was calculated by correlating the results with finite-element simulations. The obtained values were then compared with Fourier-transformed infrared spectrometry measurements. It was shown that after annealing for 2 min at 1050 °C carbon no longer has any influence on strain in the superlattice, which behaves like pure SiGe. However, a significant proportion of substitutional C atoms remain in a third-nearest neighbour (3nn) configuration. It was deduced that the influence of 3nn C on strain is negligible and that only isolated atoms have a significant contribution. It was also proposed that the 3nn configuration is an intermediary step during the formation of SiC clusters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.305
DOI: 10.1088/0268-1242/26/12/125010
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“High-temperature properties of (La,Ca)(Fe,Mg,Mo)O3-\delta perovskites as prospective electrode materials for symmetrical SOFC”. Istomin SY, Morozov AV, Abdullayev MM, Batuk M, Hadermann J, Kazakov SM, Sobolev AV, Presniakov IA, Antipov EV, Journal of solid state chemistry 258, 1 (2018). http://doi.org/10.1016/J.JSSC.2017.10.005
Abstract: La1-yCayFe0.5+x(Mg,Mo)(0.5-x)O3-delta oxides with the orthorhombic GdFeO3-type perovskite structure have been synthesized at 1573 K. Transmission electron microscopy study for selected samples shows the coexistence of domains of perovskite phases with ordered and disordered B-cations. Mossbauer spectroscopy studies performed at 300 K and 573 K show that while compositions with low Ca-content (La0.55Ca0.45Fe0.5Mg0.2625Mo0.2375O3-delta and La0.5Ca0.5Fe0.6Mg0.175Mo0.225O3-delta) are nearly oxygen stoichiometric, La0.2Ca0.8Fe0.5Mg0.2625Mo0.2375O3-delta is oxygen deficient with delta approximate to 0.15. Oxides are stable in reducing atmosphere (Ar/H-2, 8%) at 1173 K for 12 h. No additional phases have been observed at XRPD patterns of all studied perovskites and Ce1-xGdxO2-x/2 electrolyte mixtures treated at 1173-1373K, while Fe-rich compositions (x >= 0.1) react with Zr1-xYxO2-x/2 electrolyte above 1273 K. Dilatometry studies reveal that all samples show rather low thermal expansion coefficients (TECs) in air of 11.4-12.7 ppm K-1. In reducing atmosphere their TECs were found to increase up to 12.1-15.4 ppm K-1 due to chemical expansion effect. High-temperature electrical conductivity measurements in air and Ar/H-2 atmosphere show that the highest conductivity is observed for Fe- and Ca-rich compositions. Moderate values of electrical conductivity and TEC together with stability towards chemical interaction with typical SOFC electrolytes make novel Fe-containing perovskites promising electrode materials for symmetrical solid oxide fuel cell.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 5
DOI: 10.1016/J.JSSC.2017.10.005
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“Binary icosahedral clusters of hard spheres in spherical confinement”. Wang D, Dasgupta T, van der Wee EB, Zanaga D, Altantzis T, Wu Y, Coli GM, Murray CB, Bals S, Dijkstra M, van Blaaderen A, Nature Physics , 1 (2020). http://doi.org/10.1038/S41567-020-1003-9
Abstract: The influence of geometry on the local and global packing of particles is important to many fundamental and applied research themes, such as the structure and stability of liquids, crystals and glasses. Here we show by experiments and simulations that a binary mixture of hard-sphere-like nanoparticles crystallizing into a MgZn(2)Laves phase in bulk spontaneously forms icosahedral clusters in slowly drying droplets. Using advanced electron tomography, we are able to obtain the real-space coordinates of all the spheres in the icosahedral clusters of up to about 10,000 particles. The local structure of 70-80% of the particles became similar to that of the MgCu(2)Laves phase. These observations are important for photonic applications. In addition, we observed in simulations that the icosahedral clusters nucleated away from the spherical boundary, which is distinctly different from that of the single species clusters. Our findings open the way for particle-level studies of nucleation and growth of icosahedral clusters, and of binary crystallization. The authors investigate out-of-equilibrium crystallization of a binary mixture of sphere-like nanoparticles in small droplets. They observe the spontaneous formation of an icosahedral structure with stable MgCu(2)phases, which are promising for photonic applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 19.6
Times cited: 38
DOI: 10.1038/S41567-020-1003-9
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“Crack initiation in tapered high Si stainless steel specimens : stress threshold analyses”. Penders A, Konstantinovic MJ, Bosch RW, Schryvers D, Corrosion Engineering Science And Technology , 1 (2020). http://doi.org/10.1080/1478422X.2020.1785651
Abstract: Tapered specimens were used for an accelerated test technique to study the crack initiation of high Si stainless steel by means of constant elongation rate tensile testing in a simulated pressurised water reactor environment. Detailed crack density distributions were obtained by applying an advanced crack detection algorithm on iteratively displaced scanning electron microscopy pictures featuring stress corrosion cracks along the specimen's gauge length. By means of finite-element analysis, prominent peaks in the crack density graphs are demonstrated to be related to stress relief and stress build-up during the crack initiation phase. Intrinsic scatter related to the crack detection suggests that stress corrosion cracking is independent of the strain-rate for strain-rates lower than 10(-6 )s(-1). Based on the extrapolation to constant load conditions, the critical threshold value for the duplex high Si stainless steel is estimated to be around 580 MPa.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.8
Times cited: 1
DOI: 10.1080/1478422X.2020.1785651
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“DSC cycling effects on phase transformation temperatures of micron and submicron grain Ni50.8Ti49.2 microwires”. Pourbabak S, Verlinden B, Van Humbeeck J, Schryvers D, Shape memory and superelasticity , 1 (2020). http://doi.org/10.1007/S40830-020-00278-Y
Abstract: The effect of thermal cycling parameters on the phase transformation temperatures of micron and submicron grain size recrystallized Ni-Ti microwires was investigated. The suppression of martensitic transformation by thermal cycling was found to enhance when combined with room temperature aging between the cycles and enhances even more when aged at elevated temperature of 100 degrees C. While aging at room temperature alone has no clear effect on the martensitic transformation, elevated temperature aging at 100 degrees C alone suppresses the martensitic transformation. All aforementioned effects were found to be stronger in large grain samples than in small grain samples. Martensitic transformation suppression in all cases was in line with the formation of Ni4Ti3 precursors in the form of < 111 & rang;(B2) Ni clusters as concluded from the observed diffuse intensity in the electron diffraction patterns revealing short-range ordering enhancement. Performing thermal cycling in some different temperature ranges to separate the effect of martensitic transformation and high temperature range of DSC cycling revealed that both high temperature- and martensitic transformation-included cycles enhance the short-range ordering.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1007/S40830-020-00278-Y
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“Dual improvement of beta-MnO₂, oxygen evolution electrocatalysts via combined substrate control and surface engineering”. Bigiani L, Gasparotto A, Maccato C, Sada C, Verbeeck J, Andreu T, Morante JR, Barreca D, Chemcatchem , 1 (2020). http://doi.org/10.1002/CCTC.202000999
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.5
Times cited: 5
DOI: 10.1002/CCTC.202000999
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“Towards chirality control of graphene nanoribbons embedded in hexagonal boron nitride”. Wang HS, Chen L, Elibol K, He L, Wang H, Chen C, Jiang C, Li C, Wu T, Cong CX, Pennycook TJ, Argentero G, Zhang D, Watanabe K, Taniguchi T, Wei W, Yuan Q, Meyer JC, Xie X, Nature Materials , 1 (2020). http://doi.org/10.1038/S41563-020-00806-2
Abstract: Oriented trenches are created in h-BN using different catalysts, and used as templates to grow seamlessly integrated armchair and zigzag graphene nanoribbons with chirality-dependent electrical and magnetic conductance properties. The integrated in-plane growth of graphene nanoribbons (GNRs) and hexagonal boron nitride (h-BN) could provide a promising route to achieve integrated circuitry of atomic thickness. However, fabrication of edge-specific GNRs in the lattice of h-BN still remains a significant challenge. Here we developed a two-step growth method and successfully achieved sub-5-nm-wide zigzag and armchair GNRs embedded in h-BN. Further transport measurements reveal that the sub-7-nm-wide zigzag GNRs exhibit openings of the bandgap inversely proportional to their width, while narrow armchair GNRs exhibit some fluctuation in the bandgap-width relationship. An obvious conductance peak is observed in the transfer curves of 8- to 10-nm-wide zigzag GNRs, while it is absent in most armchair GNRs. Zigzag GNRs exhibit a small magnetic conductance, while armchair GNRs have much higher magnetic conductance values. This integrated lateral growth of edge-specific GNRs in h-BN provides a promising route to achieve intricate nanoscale circuits.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 41.2
Times cited: 3
DOI: 10.1038/S41563-020-00806-2
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“Twin-jet electropolishing for damage-free transmission electron microscopy specimen preparation of metallic microwires”. Pourbabak S, Orekhov A, Schryvers D, Microscopy Research And Technique , 1 (2020). http://doi.org/10.1002/JEMT.23588
Abstract: A method to prepare TEM specimens from metallic microwires and based on conventional twin-jet electropolishing is introduced. The wire is embedded in an opaque epoxy resin medium and the hardened resin is mechanically polished to reveal the wire on both sides. The resin containing wire is then cut into discs of the appropriate size. The obtained embedded wire is electropolished in a conventional twin-jet electropolishing machine until electron transparency in large areas without radiation damage is achieved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.5
DOI: 10.1002/JEMT.23588
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“Optimizing Experimental Conditions for Accurate Quantitative Energy-Dispersive X-ray Analysis of Interfaces at the Atomic Scale”. MacArthur KE, Yankovich AB, Béché, A, Luysberg M, Brown HG, Findlay SD, Heggen M, Allen LJ, Microscopy And Microanalysis , 1 (2021). http://doi.org/10.1017/S1431927621000246
Abstract: The invention of silicon drift detectors has resulted in an unprecedented improvement in detection efficiency for energy-dispersive X-ray (EDX) spectroscopy in the scanning transmission electron microscope. The result is numerous beautiful atomic-scale maps, which provide insights into the internal structure of a variety of materials. However, the task still remains to understand exactly where the X-ray signal comes from and how accurately it can be quantified. Unfortunately, when crystals are aligned with a low-order zone axis parallel to the incident beam direction, as is necessary for atomic-resolution imaging, the electron beam channels. When the beam becomes localized in this way, the relationship between the concentration of a particular element and its spectroscopic X-ray signal is generally nonlinear. Here, we discuss the combined effect of both spatial integration and sample tilt for ameliorating the effects of channeling and improving the accuracy of EDX quantification. Both simulations and experimental results will be presented for a perovskite-based oxide interface. We examine how the scattering and spreading of the electron beam can lead to erroneous interpretation of interface compositions, and what approaches can be made to improve our understanding of the underlying atomic structure.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.891
DOI: 10.1017/S1431927621000246
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“Introduction”. de Backer A, Fatermans J, den Dekker AJ, Van Aert S Advances in imaging and electron physics
T2 – Advances in imaging and electron physics. page 1 (2021).
Keywords: H2 Book chapter; Electron microscopy for materials research (EMAT)
DOI: 10.1016/BS.AIEP.2021.01.001
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“Creation of Exclusive Artificial Cluster Defects by Selective Metal Removal in the (Zn, Zr) Mixed-Metal UiO-66”. Feng X, Jena HS, Krishnaraj C, Arenas-Esteban D, Leus K, Wang G, Sun J, Rüscher M, Timoshenko J, Roldan Cuenya B, Bals S, Voort PVD, Journal Of The American Chemical Society , jacs.1c05357 (2021). http://doi.org/10.1021/jacs.1c05357
Abstract: The differentiation between missing linker defects
and missing cluster defects in MOFs is difficult, thereby limiting the
ability to correlate materials properties to a specific type of defects.
Herein, we present a novel and easy synthesis strategy for the
creation of solely “missing cluster defects” by preparing mixed-metal
(Zn, Zr)-UiO-66 followed by a gentle acid wash to remove the Zn
nodes. The resulting material has the reo UiO-66 structure, typical
for well-defined missing cluster defects. The missing clusters are
thoroughly characterized, including low-pressure Ar-sorption, iDPCSTEM
at a low dose (1.5 pA), and XANES/EXAFS analysis. We
show that the missing cluster UiO-66 has a negligible number of missing linkers. We show the performance of the missing cluster
UiO-66 in CO2 sorption and heterogeneous catalysis.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 29
DOI: 10.1021/jacs.1c05357
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“Accurate and Robust Calibration of the Uniform Affine Transformation Between Scan-Camera Coordinates for Atom-Resolved In-Focus 4D-STEM Datasets”. Ning S, Xu W, Ma Y, Loh L, Pennycook TJ, Zhou W, Zhang F, Bosman M, Pennycook SJ, He Q, Loh ND, Microscopy and microanalysis , 1 (2022). http://doi.org/10.1017/S1431927622000320
Abstract: Accurate geometrical calibration between the scan coordinates and the camera coordinates is critical in four-dimensional scanning transmission electron microscopy (4D-STEM) for both quantitative imaging and ptychographic reconstructions. For atomic-resolved, in-focus 4D-STEM datasets, we propose a hybrid method incorporating two sub-routines, namely a J-matrix method and a Fourier method, which can calibrate the uniform affine transformation between the scan-camera coordinates using raw data, without a priori knowledge about the crystal structure of the specimen. The hybrid method is found robust against scan distortions and residual probe aberrations. It is also effective even when defects are present in the specimen, or the specimen becomes relatively thick. We will demonstrate that a successful geometrical calibration with the hybrid method will lead to a more reliable recovery of both the specimen and the electron probe in a ptychographic reconstruction. We will also show that, although the elimination of local scan position errors still requires an iterative approach, the rate of convergence can be improved, and the residual errors can be further reduced if the hybrid method can be firstly applied for initial calibration. The code is made available as a simple-to-use tool to correct affine transformations of the scan-camera coordinates in 4D-STEM experiments.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.8
DOI: 10.1017/S1431927622000320
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