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“MsSpec-1.0 : a multiple scattering package for electron spectroscopies in material science”. Sébilleau D, Natoli C, Gavaza GM, Zhao H, da Pieve F, Hatada K, Computer physics communications 182, 2567 (2011). http://doi.org/10.1016/j.cpc.2011.07.012
Abstract: We present a multiple scattering package to calculate the cross-section of various spectroscopies namely photoelectron diffraction (PED), Auger electron diffraction (AED), X-ray absorption (XAS), low-energy electron diffraction (LEED) and Auger photoelectron coincidence spectroscopy (APECS). This package is composed of three main codes, computing respectively the cluster, the potential and the cross-section. In the latter case, in order to cover a range of energies as wide as possible, three different algorithms are provided to perform the multiple scattering calculation: full matrix inversion, series expansion or correlation expansion of the multiple scattering matrix. Numerous other small Fortran codes or bash/csh shell scripts are also provided to perform specific tasks. The cross-section code is built by the user from a library of subroutines using a makefile.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.936
Times cited: 6
DOI: 10.1016/j.cpc.2011.07.012
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“Nanoscale superconductivity: nanowires and nanofilms”. Shanenko AA, Croitoru MD, Peeters FM, Physica: C : superconductivity 468, 593 (2008). http://doi.org/10.1016/j.physc.2007.11.053
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 6
DOI: 10.1016/j.physc.2007.11.053
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“A new cuprate with mercury bilayers : the “2222&rdquo, oxide Hg2-xMxBa2Pr2Cu2O10-\delta (M= Cu,Pr)”. Huve M, Martin C, Maignan A, Michel C, Van Tendeloo G, Hervieu M, Raveau B, Journal of solid state chemistry 114, 230 (1995). http://doi.org/10.1006/jssc.1995.1033
Abstract: A ''2222'' cuprate with mercury bilayers (Hg1.5Cu0.2Pr0.3)Ba2Pr2Cu2O10-delta, has been synthesized for the first time. It crystallizes in the P4/nmm space group with a = 3.9072(1) Angstrom and c = 17.219(1) Angstrom. The powder XRD and HREM studies of this new cuprate show that its structure consists of an intergrowth of double pyramidal (oxygen-deficient perovskite) copper layers, with double fluorite-type layers and distorted triple rock salt layers (mercury bilayers). The structure of this phase can be deduced from that of the ''2212'' mercury cuprate (Hg1.5Cu0.2Pr0.3)Ba2PrCu2O8-delta by the introduction of one additional [PrO2]infinity fluorite layer. The regular stacking of the metallic layer and the uniform cationic distribution in the mercury bilayers are remarkable features of this cuprate. The stabilization of the mercury bilayers by praseodymium and the absence of superconductivity are discussed. (C) 1995 Academic Press, Inc.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.133
Times cited: 6
DOI: 10.1006/jssc.1995.1033
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“New erbium silicide superstructures: a study by high resolution electron microscopy”. Frangis N, Van Tendeloo G, van Landuyt J, Kaltsas G, Travlos A, Nassiopoulos AG, Physica status solidi: A: applied research 158, 107 (1996)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 6
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“New germanates RCrGeO5 (R=NdEr, Y): synthesis, structure, and properties”. Shpanchenko RV, Tsirlin AA, Kondakova ES, Antipov EV, Bougerol C, Hadermann J, Van Tendeloo G, Sakurai H, Takayama-Muromachi E, Journal of solid state chemistry 181, 2433 (2008). http://doi.org/10.1016/j.jssc.2008.05.043
Abstract: The new complex germanates RCrGeO5 (R=NdEr, Y) have been synthesized and investigated by means of X-ray powder diffraction, electron microscopy, magnetic susceptibility and specific heat measurements. All the compounds are isostructural and crystallize in the orthorhombic symmetry, space group Pbam, and Z=4. The crystal structure of RCrGeO5, as refined using X-ray powder diffraction data, includes infinite chains built by edge-sharing Cr+3O6 octahedra with two alternating Cr−Cr distances. The chains are combined into a three-dimensional framework by Ge2O8 groups consisting of two edge-linked square pyramids oriented in opposite directions. The resulting framework contains pentagonal channels where rare-earth elements are located. Thus, RCrGeO5 germanates present new examples of RMn2O5-type compounds and show ordering of Cr+3 and Ge+4 cations. Electron diffraction as well as high-resolution electron microscopy confirm the structure solution. Magnetic susceptibility data for R=Nd, Sm, and Eu are qualitatively consistent with the presence of isolated 3d (antiferromagnetically coupled Cr+3 cations) and 4f (R+3) spin subsystems in the RCrGeO5 compounds. NdCrGeO5 undergoes long-range magnetic ordering at 2.6 K, while SmCrGeO5 and EuCrGeO5 do not show any phase transitions down to 2 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 6
DOI: 10.1016/j.jssc.2008.05.043
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“New insights into the mesophase transformation of ethane-bridged PMOs by the influence of different counterions under basic conditions”. Lin F, Meng, Kukueva E, Mertens M, Van Doorslaer S, Bals S, Cool P, RSC advances 5, 5553 (2015). http://doi.org/10.1039/c4ra15849k
Abstract: The counterions are of crucial importance in determining the mesostructure and morphology of ethanebridged PMO materials synthesized under basic conditions. By using CTABr as the surfactant, the final PMO materials show a 2-D hexagonal (p6mm) mesophase, while PMO materials with cubic (Pm (3) over barn ) mesostructure are obtained when CTACl or CTA(SO4)(1)/(2) are used. With gradually replacing CTABr by CTACl or CTA(SO4) (1)/(2) while keeping the total surfactant concentration constant, a clear p6mm to Pm (3) over barn 3n mesophase evolution process is observed. For a given gel composition, the mesophase of ethanebridged PMO materials can also be adjusted by the addition of different sodium salts. In short, the effect of the counterions on the mesophase can be attributed to the binding strength of the ions on the surfactant micelles, which follows the Hofmeister series (SO42- < Cl- < Br-< NO3- < SCN-). Furthermore, it is found that the hydrolysis and condensation rate of the organosilica precursor also plays an important role in the formation of the final mesostructure
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.108
Times cited: 6
DOI: 10.1039/c4ra15849k
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“Observation of nanostripes and -clusters in (Nd, EuGd)Ba2Cu3Ox superconductors”. Koblischka MR, Winter M, Das P, Koblischka-Veneva A, Muralidhar M, Wolf T, Babu NH, Turner S, Van Tendeloo G, Hartmann U, Physica: C : superconductivity 469, 168 (2009). http://doi.org/10.1016/j.physc.2009.01.007
Abstract: Nanostripes are observed in melt-textured and single-crystalline samples of the ternary light rare earth (LRE)-compound (Nd0.33Eu0.33Gd0.33)Ba2Cu3Ox (NEG) by means of atomic force microscopy, scanning tunnelling microscopy at ambient conditions, combined with transmission electron microscopy and electron backscatter diffraction. This enables the observation of several important features: The nanostripes are formed by chains of nanoclusters, representing the LRE/Ba substitution. The dimensions of the nanostripes are similar for both types of NEG samples. The periodicity of the nanostripes is found to range between 40 and 60 nm; the shape of the nanoclusters is elliptic with a major axis length between 300 and 500 nm and a minor axis length of about 30150 nm. The stripes are filling effectively the space in between the twin boundaries. Concerning the flux pinning, the nanoclusters are the important pinning sites, not the nanostripes themselves.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 6
DOI: 10.1016/j.physc.2009.01.007
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“Optimisation of superconducting thin films by TEM”. Bals S, Van Tendeloo G, Rijnders G, Blank DHA, Leca V, Salluzzo M, Physica: C : superconductivity 372/376, 711 (2002). http://doi.org/10.1016/S0921-4534(02)00838-9
Abstract: High-resolution electron microscopy is used to study the initial growth of different REBa2CU3O7-5 thin films. In DyBa2CU3O7-5 ultra-thin films, deposited on TiO2 terminated SrTiO3, two different types of interface arrangements occur: bulk-SrO-TiO2-BaO-CuO-BaO-CuO2-Dy-CuO2-BaO-bulk and bulk-SrO-TiO2-BaO-CuO2-Dy-CuO2-BaO-CuO-BaO-bulk. This variable growth sequence is the origin of the presence of antiphase boundaries. In Nd1+xBa2-xCu3O7-5 thin films, antiphase boundaries tend to annihilate by the insertion of extra Nd-layers. This annihilation is correlated with the flat morphology of the film and the absence of growth spirals at the surface of the Nd-rich films. (C) 2002 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 6
DOI: 10.1016/S0921-4534(02)00838-9
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“The paraelectric-ferroelectric phase transition of Bi4Ti3O12 studied by electron microscopy”. Nistor L, Van Tendeloo G, Amelinckx S, Phase transitions 59, 135 (1996)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.954
Times cited: 6
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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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“Selective decoration of isolated carbon nanotubes by potassium evaporation : scanning photoemission microscopy and density functional theory”. Struzzi C, Erbahar D, Scardamaglia M, Amati M, Gregoratti L, Lagos, Van Tendeloo G, Snyders R, Ewels C, Bittencourt C, Journal of materials chemistry C : materials for optical and electronic devices 3, 2518 (2015). http://doi.org/10.1039/c4tc02478h
Abstract: Site selective doping of aligned carbon nanostructures represents a promising approach for their implementation in actual devices. In the present work we report on alkali metals decoration on low density vertically aligned carbon nanotubes, disclosing the possibility of engineering site selective depositions of potassium atoms on the carbon systems. Photoemission measurements were combined with microscopy demonstrating the effective spatial control of alkali deposition. The changes of electronic structures of locally doped carbon regions were studied by exploiting the ability of the scanning photoemission microscopy technique. From the analysis of experimental data supported by theoretical calculations, we show the tuning of the charge transfer from potassium to carbon atoms belonging to neighboring nanotubes or along the same tube structure.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.256
Times cited: 6
DOI: 10.1039/c4tc02478h
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“Structural defects and epitaxial rotation of C60 and C70 (111) films on GeS(001)”. Bernaerts D, Van Tendeloo G, Amelinckx S, Hevesi K, Gensterblum G, Yu LM, Pireaux JJ, Grey F, Bohr J, Journal of applied physics 80, 3310 (1996). http://doi.org/10.1063/1.363241
Abstract: A transmission electron microscopy study of epitaxial C-60 and C-70 films grown on a GeS (001) surface is presented. The relationship between the orientation of the substrate and the films and structural defects in the films, such as grain boundaries, unknown in bulk C-60 and C-70 crystals, are studied. Small misalignments of the overlayers with respect to the orientation of the substrate, so-called epitaxial rotations, exist mainly in C-70 films, but also sporadically in the C-60 overlayers. A simple symmetry model, previously used to predict the rotation of hexagonal overlayers on hexagonal substrates, is numerically tested and applied to the present situation. Some qualitative conclusions concerning the substrate-film interaction are deduced. (C) 1996 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.183
Times cited: 6
DOI: 10.1063/1.363241
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“Structure and formation mechanism of rolled-in oxide areas on aluminum lithographic printing sheets”. Tzedaki G, M, Turner S, Godet S, De Graeve I, Kernig B, Hasenclever J, Terryn H, Scripta materialia 68, 233 (2013). http://doi.org/10.1016/j.scriptamat.2012.10.021
Abstract: The subsurface area introduced during rolling on the 1100 aluminum alloy series alters its surface properties, which makes it more susceptible to corrosion. A combination of different transmission electron microscopy techniques is employed to observe the orientation of small grain structures and the distribution elements in the subsurface layer. This approach provided valuable insight into the formation mechanism of the layer and the phenomena taking place during rolling.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.747
Times cited: 6
DOI: 10.1016/j.scriptamat.2012.10.021
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“Bi0.75Sr0.25FeO3-\delta : revealing order/disorder phenomena by combining diffraction techniques”. Pachoud E, Bréard Y, Martin C, Maignan A, Abakumov AM, Suard E, Smith RI, Suchomel MR, Solid state communications 152, 331 (2012). http://doi.org/10.1016/j.ssc.2011.12.023
Abstract: The local and long range structure of polycrystalline samples of Bi0.75Sr0.25FeO3-delta has been probed by neutron and synchrotron X-ray diffraction coupled with transmission electron microscopy. It is found that the long range structure on average can be described by the cubic space group Pm-3m (a(p) congruent to 3.951 angstrom). However, the refinements revealed large atomic displacements for the (Bi, Sr) cations and the oxygen atoms from their ideal positions. The electron microscopy study indicates the existence of local phenomena like local ordering of oxygen vacancies, which are segregated at the randomly spaced parallel (FeO2-delta) planes, or the existence of region of different symmetry, probably R3c. At room temperature, the compound exhibits G-type antiferromagnetism (T-N congruent to 650 K) with a magnetic moment of congruent to 3.7 mu(B). (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.554
Times cited: 6
DOI: 10.1016/j.ssc.2011.12.023
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“(CuCl)LaTa2O\text{7} and quantum phase transition in the (CuX)LaM2O7 family (X=Cl, Br, M=Nb, Ta)”. Tsirlin AA, Abakumov AM, Ritter C, Rosner H, Physical review : B : condensed matter and materials physics 86, 064440 (2012). http://doi.org/10.1103/PhysRevB.86.064440
Abstract: We apply neutron diffraction, high-resolution synchrotron x-ray diffraction, magnetization measurements, electronic structure calculations, and quantum Monte-Carlo simulations to unravel the structure and magnetism of (CuCl)LaTa2O7. Despite the pseudo-tetragonal crystallographic unit cell, this compound features an orthorhombic superstructure, similar to the Nb-containing (CuX)LaNb2O7 with X = Cl and Br. The spin lattice entails dimers formed by the antiferromagnetic fourth-neighbor coupling J(4), as well as a large number of nonequivalent interdimer couplings quantified by an effective exchange parameter J(eff). In (CuCl)LaTa2O7, the interdimer couplings are sufficiently strong to induce the long-range magnetic order with the Neel temperature T-N similar or equal to 7 K and the ordered magnetic moment of 0.53 mu(B), as measured with neutron diffraction. This magnetic behavior can be accounted for by J(eff)/J(4) similar or equal to 1.6 and J(4) similar or equal to 16 K. We further propose a general magnetic phase diagram for the (CuCl)LaNb2O7-type compounds, and explain the transition from the gapped spin-singlet (dimer) ground state in (CuCl)LaNb2O7 to the long-range antiferromagnetic order in (CuCl)LaTa2O7 and (CuBr)LaNb2O7 by an increase in the magnitude of the interdimer couplings J(eff)/J(4), with the (CuCl)LaM2O7 (M = Nb, Ta) compounds lying on different sides of the quantum critical point that separates the singlet and long-range-ordered magnetic ground states.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.86.064440
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“The use of convergent beam electron diffraction for stress measurements in shallow trench isolation structures”. Stuer C, van Landuyt J, Bender H, Rooyackers R, Badenes G, Materials science in semiconductor processing 4, 117 (2001). http://doi.org/10.1016/S1369-8001(00)00110-4
Abstract: Shallow trench isolation (STI) is a promising technology for the isolation structures of the new generation of ULSI devices with dimensions below 0.18 mum. The various processing steps cause stress fields in STI structures, which can lead to defect formation in the silicon substrate. In their turn, stress fields affect the electrical parameters and the reliability of devices. Convergent beam electron diffraction (CBED) is used in this study to examine the influence of a wet and a dry pre-gate oxidation on the stress distribution around STI structures. The measurements are performed on STI structures with different width and spacing. CBED analysis is compared with bright-field TEM images. Defects are observed in high-strain areas of small isolated structures. (C) 2001 Elsevier Science Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.359
Times cited: 6
DOI: 10.1016/S1369-8001(00)00110-4
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“Transmission electron microscopy study of polymorphism in barium gallate BaGa2O4”. Lemmens H, Amelinckx S, Van Tendeloo G, Abakumov AM, Rozova MG, Antipov EV, Phase transitions 76, 653 (2003). http://doi.org/10.1080/0141159021000051055
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.06
Times cited: 6
DOI: 10.1080/0141159021000051055
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“A pseudo-tetragonal tungsten bronze superstructure: a combined solution of the crystal structure of K6.4(Nb,Ta)36.3O94 with advanced transmission electron microscopy and neutron diffraction”. Paria Sena R, Babaryk AA, Khainakov S, Garcia-Granda S, Slobodyanik NS, Van Tendeloo G, Abakumov AM, Hadermann J, Journal of the Chemical Society : Dalton transactions 45, 973 (2016). http://doi.org/10.1039/c5dt03479e
Abstract: The crystal structure of the K6.4Nb28.2Ta8.1O94 pseudo-tetragonal tungsten bronze-type oxide was determined using a combination of X-ray powder diffraction, neutron diffraction and transmission electron microscopy techniques, including electron diffraction, high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field STEM (ABF-STEM) and energy-dispersive X-ray compositional mapping (STEM-EDX). The compound crystallizes in the space group Pbam with unit cell parameters a = 37.468(9) A, b = 12.493(3) A, c = 3.95333(15) A. The structure consists of corner sharing (Nb,Ta)O6 octahedra forming trigonal, tetragonal and pentagonal tunnels. All tetragonal tunnels are occupied by K(+) ions, while 1/3 of the pentagonal tunnels are preferentially occupied by Nb(5+)/Ta(5+) and 2/3 are occupied by K(+) in a regular pattern. A fractional substitution of K(+) in the pentagonal tunnels by Nb(5+)/Ta(5+) is suggested by the analysis of the HAADF-STEM images. In contrast to similar structures, such as K2Nb8O21, also parts of the trigonal tunnels are fractionally occupied by K(+) cations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.029
Times cited: 6
DOI: 10.1039/c5dt03479e
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“Anatase TiO2nanoparticle coating on porous COK-12 platelets as highly active and reusable photocatalysts”. Wee LH, Meledina M, Turner S, Custers K, Kerkhofs S, Sree SP, Gobechiya E, Kirschhock CEA, Van Tendeloo G, Martens JA, RSC advances 6, 46678 (2016). http://doi.org/10.1039/C6RA06141A
Abstract: Nanoscale TiO2 photocatalysts are widely used for biomedical applications, self-cleaning processes and wastewater treatments. The impregnation/deposition of TiO2 nanoparticles is indispensable for facile handling and separation as well as the improvement of their photocatalytic performance. In the present study, ordered mesoporous COK-12 silica thin platelets with a high-aspect-ratio and rough surfaces are demonstrated as a potential nanoporous support for homogeneous TiO2 nanoparticle coatings with high loading up to 16.7 wt%. The photocatalytic composite of COK-12 platelets and TiO2 nanoparticles is characterized in detail by HRSEM, SAXS, XRD, N2 physisorption analysis, solid-state UV-vis spectroscopy, HAADF-STEM, EDX analysis, and electron tomography. HAADF-STEM-EDX and electron tomography studies reveal a homogeneous dispersion of nanosized TiO2 nanoparticles over COK-12 platelets. The final composite material with anatase TiO2 nanoparticles that demonstrate a blueshifted semiconductor band gap energy of 3.2 eV coated on a highly porous COK-12 support shows exceptional photocatalytic catalytic activity for photodegradation of organic dyes (rhodamine 6G and methylene blue) and an organic pollutant (1-adamantanol) under UV light radiation, outperforming the commercial P25 TiO2 (Degussa) catalyst.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 6
DOI: 10.1039/C6RA06141A
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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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“Detecting and locating light atoms from high-resolution STEM images: The quest for a single optimal design”. Gonnissen J, De Backer A, den Dekker AJ, Sijbers J, Van Aert S, Ultramicroscopy 170, 128 (2016). http://doi.org/10.1016/j.ultramic.2016.07.014
Abstract: In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of light atoms from HR STEM images. To determine the optimal experiment design for locating light atoms, use is made of the so-called Cramer-Rao Lower Bound (CRLB). It is investigated if a single optimal design can be found for both the detection and location problem of light atoms. Furthermore, the incoming electron dose is optimised for both research goals and it is shown that picometre range precision is feasible for the estimation of the atom positions when using an appropriate incoming electron dose under the optimal detector settings to detect light atoms.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 2.843
Times cited: 6
DOI: 10.1016/j.ultramic.2016.07.014
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“Dislocation and back stress dominated viscoplasticity in freestanding sub-micron Pd films”. Lemoine G, Delannay L, Idrissi H, Colla M-S, Pardoen T, Acta materialia 111, 10 (2016). http://doi.org/10.1016/j.actamat.2016.03.038
Abstract: A dislocation-based crystal plasticity model is developed in order to study the mechanical and creep/ relaxation behaviour of polycrystalline metallic thin films. The model accounts for the confinement of plasticity due to grain boundaries and for the anisotropy of individual grains, as well as for the significant viscoplastic effects associated to dislocation dominated thermally activated mechanisms. Numerical predictions are assessed based on experimental tensile test followed by relaxation on freestanding Pd films, based on an on-chip test technique. The dislocation-based mechanism assumption captures all the experimental trends, including the stress strain response, the relaxation behaviour and the dislocation density evolution, confirming the dominance of a dislocation driven deformation mechanism for the present Pd films with high defects density. The model has also been used to address some original experimental evidences involving back stresses, Bauschinger effect, backward creep and strain recovery. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
Times cited: 6
DOI: 10.1016/j.actamat.2016.03.038
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“Square-centimeter-sized high-efficiency polymer solar cells : how the processing atmosphere and film quality influence performance at large scale”. Ben Dkhil S, Pfannmöller M, Bals S, Koganezawa T, Yoshimoto N, Hannani D, Gaceur M, Videlot-Ackermann C, Margeat O, Ackermann J, Laser physics review 6, 1600290 (2016). http://doi.org/10.1002/aenm.201600290
Abstract: Organic solar cells based on two benzodithiophene-based polymers (PTB7 and PTB7-Th) processed at square centimeter-size under inert atmosphere and ambient air, respectively, are investigated. It is demonstrated that the performance of solar cells processed under inert atmosphere is not limited by the upscaling of photoactive layer and the interfacial layers. Thorough morphological and electrical characterizations of optimized layers and corresponding devices reveal that performance losses due to area enlargement are only caused by the sheet resistance of the transparent electrode reducing the effi ciency from 9.3% of 7.8% for PTB7-Th in the condition that both photoactive layer and the interfacial layers are of high layer quality. Air processing of photoactive layer and the interfacial layers into centimeter-sized solar cells lead to additional, but only slight, losses (< 10%) in all photovoltaic parameters, which can be addressed to changes in the electronic properties of both active layer and ZnO layers rather than changes in layer morphology. The demonstrated compatibility of polymer solar cells using solution-processed photoactive layer and interfacial layers with large area indicates that the introduction of a standard active area of 1 cm(2) for measuring effi ciency of organic record solar cells is feasible. However electric standards for indium tin oxides (ITO) or alternative transparent electrodes need to be developed so that performance of new photovoltaic materials can be compared at square centimeter-size.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 16.721
Times cited: 6
DOI: 10.1002/aenm.201600290
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“Unique nanostructural features in Fe, Mn-doped YBCO thin films”. Meledin A, Turner S, Cayado P, Mundet B, Solano E, Ricart S, Ros J, Puig T, Obradors X, Van Tendeloo G, Superconductor science and technology 29, 125009 (2016). http://doi.org/10.1088/0953-2048/29/12/125009
Abstract: An attempt to grow a thin epitaxial composite film of YBa2Cu3O7−δ (YBCO) with spinel MnFe2O4 (MFO) nanoparticles on a LAO substrate using the CSD approach resulted in a decomposition of the spinel and various doping modes of YBCO with the Fe and Mn cations. These nanostructural effects lead to a lowering of T c and a slight J c increase in field. Using a combination of advanced transmission electron microscopy (TEM) techniques such as atomic resolution high-angle annular dark field scanning TEM, energy dispersive x-ray spectroscopy and electron energy-loss spectroscopy we have been able to decipher and characterize the effects of the Fe and Mn doping on the film architecture. The YBaCuFeO5 anion-deficient double perovskite phase was detected in the form of 3D inclusions as well as epitaxially grown lamellas within the YBCO matrix. These nano-inclusions play a positive role as pinning centers responsible for the J c/J sf (H) dependency smoothening at high magnetic fields in the YBCO-MFO films with respect to the pristine YBCO films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 6
DOI: 10.1088/0953-2048/29/12/125009
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“Complex Microstructure and Magnetism in Polymorphic CaFeSeO”. Cassidy SJ, Batuk M, Batuk D, Hadermann J, Woodruff DN, Thompson AL, Clarke SJ, Inorganic chemistry 55, 10714 (2016). http://doi.org/10.1021/acs.inorgchem.6b01951
Abstract: The structural complexity of the antiferromagnetic oxide selenide CaFeSeO is described. The compound contains puckered FeSeO layers composed of FeSe2O2 tetrahedra sharing all their vertexes. Two polymorphs coexist that can be derived from an archetype BaZnSO structure by cooperative tilting of the FeSe2O2 tetrahedra. The polymorphs differ in the relative arrangement of the puckered layers of vertex-linked FeSe2O2 tetrahedra. In a noncentrosymmetric Cmc21 polymorph (a = 3.89684(2) A, b = 13.22054(8) A, c = 5.93625(2) A) the layers are related by the C-centering translation, while in a centrosymmetric Pmcn polymorph, with a similar cell metric (a = 3.89557(6) A, b = 13.2237(6) A, c = 5.9363(3) A), the layers are related by inversion. The compound shows long-range antiferromagnetic order below a Neel temperature of 159(1) K with both polymorphs showing antiferromagnetic coupling via Fe-O-Fe linkages and ferromagnetic coupling via Fe-Se-Fe linkages within the FeSeO layers. The magnetic susceptibility also shows evidence for weak ferromagnetism which is modeled in the refinements of the magnetic structure as arising from an uncompensated spin canting in the noncentrosymmetric polymorph. There is also a spin glass component to the magnetism which likely arises from the disordered regions of the structure evident in the transmission electron microscopy.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 6
DOI: 10.1021/acs.inorgchem.6b01951
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“Structural chemistry and magnetic properties of the perovskite SrLa2Ni2TeO9”. Sena RP, Hadermann J, Chin C-M, Hunter EC, Battle PD, Journal of solid state chemistry 243, 304 (2016). http://doi.org/10.1016/J.JSSC.2016.09.004
Abstract: A polycrystalline sample of SrLa2Ni2TeO9 has been synthesized using a standard ceramic method and characterized by neutron diffraction, magnetometry and electron microscopy. The compound adopts a monoclinic, perovskite-like structure with space group P2(1)/n in and unit cell parameters a=5.6008(1), b = 5.5872(1), c=7.9018(2) angstrom, p=90.021(6)degrees at room temperature. The two crystallographically-distinct B sites are occupied by Ni2+ and Te6+ in ratios of 83:17 and 50:50. Both ac and dc magnetometry suggest that the compound is a spin glass below 35 K but the neutron diffraction data show that some regions of the sample are antiferromagnetic. Electron microscopy revealed twinning on a nanoscale and local variations in composition. These defects are thought to be responsible for the presence of two distinct types of antiferromagnetic ordering. (C) 2016 The Authors. Published by Elsevier Inc.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 6
DOI: 10.1016/J.JSSC.2016.09.004
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“The mechanical behavior during (de)lithiation of coated silicon nanoparticles as anode material for lithium-ion batteries studied by InSitu transmission electron microscopy”. Van Havenbergh K, Turner S, Marx N, Van Tendeloo G, Energy technology 4, 1005 (2016). http://doi.org/10.1002/ENTE.201600057
Abstract: One approach to cope with the continuous irreversible capacity loss in Si-based electrodes, attributed to lithiation-induced volume changes and the formation of a solid-electrolyte interface (SEI), is by coating silicon nanoparticles. A coating can improve the conductivity of the electrode, form a chemical shield against the electrolyte, or provide mechanical confinement to reduce the volume increase. The influence of such a coating on the mechanical behavior of silicon nanoparticles during Li insertion and Li extraction was investigated by insitu transmission electron microscopy. The type of coating was shown to influence the size of the unreacted core that remains after reaction of silicon with lithium. Furthermore, two mechanisms to relieve the stress generated during volume expansion are reported: the initiation of cracks and the formation of nanovoids. Both result in a full reaction of the silicon nanoparticles, whereas with the formation of cracks, additional surface area is created, on which an SEI can be formed.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.789
Times cited: 6
DOI: 10.1002/ENTE.201600057
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“Tilted BaHfO3 nanorod artificial pinning centres in REBCO films on inclined substrate deposited-MgO coated conductor templates”. Stafford BH, Sieger M, Ottolinger R, Meledin A, Strickland NM, Wimbush SC, Van Tendeloo G, Huehne R, Schultz L, Superconductor science and technology 30, 055002 (2017). http://doi.org/10.1088/1361-6668/AA621D
Abstract: We grow BaHfO3 (BHO) nanorods in REBa2Cu3O7-x (REBCO, RE: Gd or Y) thin films on metal tapes coated with the inclined substrate deposited (ISD)-MgO template by both electron beam physical vapour deposition and pulsed laser deposition. In both cases the nanorods are inclined by an angle of 21 degrees-29 degrees with respect to the sample surface normal as a consequence of the tilted growth of the REBCO film resulting from the ISD-MgO layer. We present angular critical current density (J(c)) anisotropy as well as field- and temperature-dependant J(c) data of the BHO nanorod-containing GdBCO films demonstrating an increase in J(c) over a wide range of temperatures between 30 and 77 K and magnetic fields up to 8 T. In addition, we show that the angle of the peak in the J(c) anisotropy curve resulting from the nanorods is dependent both on temperature and magnetic field. The largest J(c) enhancement from the addition of the nanorods was found to occur at 30 K, 3 T, resulting in a J(c) of 3.0 MA cm(-2).
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 6
DOI: 10.1088/1361-6668/AA621D
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“Towards rapid nanoscale measurement of strain in III-nitride heterostructures”. Jones E, Cooper D, Rouvière J-L, Béché, A, Azize M, Palacios T, Gradecak S, Applied Physics Letters 103, 231904 (2013). http://doi.org/10.1063/1.4838617
Abstract: We report the structural and compositional nanoscale characterization of InAlN/GaN nanoribbon-structured high electron mobility transistors (HEMTs) through the use of geometric phase analysis (GPA) and nanobeam electron diffraction (NBED). The strain distribution in the HEMT layer is quantified and compared to the expected strain profile for the nominal structure predicted by finite element analysis (FEA). Using the experimental strain results, the actual structure is determined and used to modify the FEA model. The improved fit of the model demonstrates that GPA and NBED provide a powerful platform for routine and rapid characterization of strain in III-V semiconducting device systems leading to insights into device evolution during processing and future device optimization.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 6
DOI: 10.1063/1.4838617
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“Magnetic properties of the 6H perovskite Ba3Fe2TeO9”. Tang Y, Sena RP, Aydeev M, Battle PD, Cadogan JM, Hadermann J, Hunter EC, Journal of solid state chemistry 253, 347 (2017). http://doi.org/10.1016/J.JSSC.2017.06.019
Abstract: A polycrystalline sample of Ba3Fe2TeO9 having the 6H perovskite structure has been prepared in a solid-state reaction and studied by a combination of electron microscopy, Mossbauer spectroscopy, magnetometry, X-ray diffraction and neutron diffraction. Partial ordering of Fe3+ and Te6+ cations occurs over the six-coordinate sites; the corner-sharing octahedra are predominantly occupied by the former and the face-sharing octahedra by a 1:1 mixture of the two. On cooling through the temperature range 18 < T/K < 295 an increasing number of spins join an antiferromagnetic backbone running through the structure while the remainder show complex relaxation effects. At 3 K an antiferromagnetic phase and a spin glass coexist.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 6
DOI: 10.1016/J.JSSC.2017.06.019
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