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“Off-stoichiometry effects on the crystalline and defect structure of hexagonal manganite REMnO3 films (RE = Y, Er, Dy)”. Gélard J, Jehanathan N, Roussel H, Gariglio S, Lebedev OI, Van Tendeloo G, Dubourdieu C, Chemistry of materials 23, 1232 (2011). http://doi.org/10.1021/cm1029358
Abstract: The crystalline and defect structure of epitaxial hexagonal RExMnyO3 (RE = Er, Dy) films with varying cationic composition was investigated by X-ray diffraction and transmission electron microscopy. The films are composed of a strained layer at the interface with the substrate and of a relaxed layer on top of it. The critical thickness is of 10 to 25 nm. For Mn-rich films (or RE deficient), an off-stoichiometric composition maintaining the hexagonal LuMnO3-type structure is stabilized over a large range of the RE/Mn ratio (0.72−1.00), with no Mn-rich secondary phases observed. A linear dependence of the out-of-plane lattice parameter with RE/Mn is observed in this range. Out-of-phase boundary (OPB) extended defects are observed in all films and exhibit a local change in stoichiometry. Such a large solubility limit in the RE deficient region points toward the formation of vacancies on the RE site (RExMnO3−δ, with 0.72 ≤ x < 1), a phenomenon that is encountered in perovskite manganites such as LaxMnO3−δ (x < 1) and that may strongly impact the physical properties of hexagonal manganites.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 17
DOI: 10.1021/cm1029358
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“Phase competition between Y2BaCuO5 and Y2O3 precipitates in Y-rich YBCO thin films”. Scotti di Uccio U, Miletto Granozio F, di Chiara A, Tafuri F, Lebedev OI, Verbist K, Van Tendeloo G, Physica: C : superconductivity 321, 162 (1999)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 17
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“Synthesis and structural study of hexagonal pervoskites in the Ba5>Ta4O15-MZrO3 (M=Ba, Sr) system”. Abakumov AM, Shpanchenko RV, Antipov EV, Lebedev OI, Van Tendeloo G, Amelinckx S, Journal of solid state chemistry 141, 492 (1998). http://doi.org/10.1006/jssc.1998.8001
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 17
DOI: 10.1006/jssc.1998.8001
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“Synthesis of highly stable pure-silica thin-walled hexagonally ordered mesoporous material”. Verlooy P, Aerts A, Lebedev OI, Van Tendeloo G, Kirschhock C, Martens JA, Chemical communications , 4287 (2009). http://doi.org/10.1039/b901796h
Abstract: Hexagonally ordered mesoporous silica with a very narrow mesopore size distribution and exceptionally high stability paired with unusually thin pore walls was prepared using piperidine and cetyltrimethylammonium bromide.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 17
DOI: 10.1039/b901796h
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“Thin films and superlattices of multiferroic hexagonal rare earth manganites”. Dubourdieu C, Huot G, Gelard I, Roussel H, Lebedev OI, Van Tendeloo G, Philosophical magazine letters 87, 203 (2007). http://doi.org/10.1080/09500830601137173
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.941
Times cited: 17
DOI: 10.1080/09500830601137173
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“Insights on growth and nanoscopic investigation of uncommon iron oxide polymorphs”. Carraro G, Maccato C, Bontempi E, Gasparotto A, Lebedev OI, Turner S, Depero LE, Van Tendeloo G, Barreca D, European journal of inorganic chemistry , 5454 (2013). http://doi.org/10.1002/ejic.201300873
Abstract: Si(100)-supported Fe2O3 nanomaterials were developed by a chemical vapor deposition (CVD) approach. The syntheses, which were performed at temperatures between 400 and 550 °C, selectively yielded the scarcely studied β- and ϵ-Fe2O3 polymorphs under O2 or O2 + H2O reaction environments, respectively. Correspondingly, the observed morphology underwent a progressive evolution from interconnected nanopyramids to vertically aligned nanorods. The present study aims to provide novel insights into Fe2O3 nano-organization by a systematic investigation of the system structure/morphology and of their interrelations with growth conditions. In particular, for the first time, the β- and ϵ-Fe2O3 preparation process has been accompanied by a thorough multitechnique investigation, which, beyond X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FESEM), is carried out by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDXS), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), scanning TEM electron energy-loss spectroscopy (STEM-EELS), and high-angle annular dark-field STEM (HAADF-STEM). Remarkably, the target materials showed a high structural and compositional homogeneity throughout the whole thickness of the nanodeposit. In particular, spatially resolved EELS chemical maps through the spectrum imaging (SI) technique enabled us to gain important information on the local Fe coordination, which is of crucial importance in determining the system reactivity. The described preparation method is in fact a powerful tool to simultaneously tailor phase composition and morphology of iron(III) oxide nanomaterials, the potential applications of which include photocatalysis, magnetic devices, gas sensors, and anodes for Li-ion batteries.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.444
Times cited: 18
DOI: 10.1002/ejic.201300873
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“Rational synthesis of a nanocrystalline calcium phosphate cement exhibiting rapid conversion to hydroxyapatite”. Neira IS, Kolen'ko YV, Lebedev OI, Van Tendeloo G, Gupta HS, Matsushita N, Yoshimura M, Guitian F, Materials science and engineering: part C: biomimetic materials 29, 2124 (2009). http://doi.org/10.1016/j.msec.2009.04.011
Abstract: The rational synthesis, comprehensive characterization, and mechanical and micromechanical properties of a calcium phosphate cement are presented. Hydroxyapatite cement biomaterial was synthesized from reactive sub-micrometer-sized dicalcium phosphate dihydrate and tetracalcium phosphate via a dissolution-precipitation reaction using water as the liquid phase. As a result nanostructured, Ca-deficient and carbonated B-type hydroxyapatite is formed. The cement shows good processibility, sets in 22 ± 2 min and entirely transforms to the end product after 6 h of setting reaction, one of the highest conversion rates among previously reported for calcium phosphate cements based on dicalcium and tetracalcium phosphates. The combination of all elucidated physical-chemical traits leads to an essential bioactivity and biocompatibility of the cement, as revealed by in vitro acellular simulated body fluid and cell culture studies. The compressive strength of the produced cement biomaterial was established to be 25 ± 3 MPa. Furthermore, nanoindentation tests were performed directly on the cement to probe its local elasticity and plasticity at sub-micrometer/micrometer level. The measured elastic modulus and hardness were established to be Es = 23 ± 3.5 and H = 0.7 ± 0.2 GPa, respectively. These values are in close agreement with those reported in literature for trabecular and cortical bones, reflecting good elastic and plastic coherence between synthesized cement biomaterial and human bones.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.164
Times cited: 18
DOI: 10.1016/j.msec.2009.04.011
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“Defect controlled room temperature ferromagnetism in Co-doped barium titanate nanocrystals”. Ray S, Kolen'ko YV, Kovnir KA, Lebedev OI, Turner S, Chakraborty T, Erni R, Watanabe T, Van Tendeloo G, Yoshimura M, Itoh M, Nanotechnology 23, 025702 (2012). http://doi.org/10.1088/0957-4484/23/2/025702
Abstract: Defect mediated high temperature ferromagnetism in oxide nanocrystallites is the central feature of this work. Here, we report the development of room temperature ferromagnetism in nanosized Co-doped barium titanate particles with a size of around 14 nm, synthesized by a solvothermal drying method. A combination of x-ray diffraction with state-of-the-art electron microscopy techniques confirms the intrinsic doping of Co into BaTiO3. The development of the room temperature ferromagnetism was tracked down to the different donor defects, namely hydroxyl groups at the oxygen site (\mathrm {OH}\mathrm {(O)}
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 19
DOI: 10.1088/0957-4484/23/2/025702
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“Electron energy-loss spectroscopy study of a (LaMnO3)8(SrMnO3)4 heterostructure”. Verbeeck J, Lebedev OI, Van Tendeloo G, Silcox J, Mercey B, Hervieu M, Haghiri-Gosnet AM, Applied physics letters 79, 2037 (2001). http://doi.org/10.1063/1.1403316
Abstract: An epitaxially grown heterostructure consisting of alternating layers of LaMnO3 (8 unit cells) and SrMnO3 (4 unit cells) on a SrTiO3 substrate has been studied by a combination of electron energy-loss spectroscopy (EELS) and high-resolution transmission electron microscopy (HRTEM) on an atomic scale. Excitation edges of all elements are captured with subnanometer spatial accuracy, and parametrized to obtain chemical profiles. The fine-edge structure of O K and Mn L-2,L-3 edges are interpreted as signatures of the local electronic structure and show a spatial modulation of the concentration of holes with O 2p character. The chemical concentration is found to be different for the bottom and top interface of a SrMnO3 layer. HRTEM complements the EELS results and confirms the asymmetry of the interfaces. (C) 2001 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 19
DOI: 10.1063/1.1403316
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“Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene”. Vernimmen J, Guidotti M, Silvestre-Albero J, Jardim EO, Mertens M, Lebedev OI, Van Tendeloo G, Psaro R, Rodríguez-Reinoso F, Meynen V, Cool P, Langmuir: the ACS journal of surfaces and colloids 27, 3618 (2011). http://doi.org/10.1021/la104808v
Abstract: Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.833
Times cited: 19
DOI: 10.1021/la104808v
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“Magnetodielectric CuCr0.5V0.5O2 : an example of a magnetic and dielectric multiglass”. Singh K, Maignan A, Simon C, Kumar S, Martin C, Lebedev O, Turner S, Van Tendeloo G, Journal of physics : condensed matter 24, 226002 (2012). http://doi.org/10.1088/0953-8984/24/22/226002
Abstract: The complex dielectric susceptibility and spin glass properties of polycrystalline CuCr0.5V 0.5O2 delafossite have been investigated. Electron diffraction, high resolution electron microscopy and electron energy loss spectroscopy show that the Cr3+ and V 3+ magnetic cations are randomly distributed on the triangular network of CdI2-type layers. In contrast to CuCrO2, CuCr0.5V 0.5O2 exhibits two distinctive (magnetic and electric) glassy states evidenced by memory effects in electric and magnetic susceptibilities. A large magnetodielectric coupling is observed at low temperature.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.649
Times cited: 19
DOI: 10.1088/0953-8984/24/22/226002
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“Catalytic characterization of pure SnO2 and GeO2 in methanol steam reforming”. Zhao Q, Lorenz H, Turner S, Lebedev OI, Van Tendeloo G, Rameshan C, Klötzer B, Konzett J, Penner S, Applied catalysis : A : general 375, 188 (2010). http://doi.org/10.1016/j.apcata.2009.12.027
Abstract: Structural changes of a variety of different SnO, SnO2 and GeO2 catalysts upon reduction in hydrogen were correlated with associated catalytic changes in methanol steam reforming. Studied systems include SnO, SnO2 and GeO2 thin film model catalysts prepared by vapour phase deposition and growth on polycrystalline NaCl surfaces and, for comparison, the corresponding pure oxide powder catalysts. Reduction of both the SnO2 thin film and powder at around 673 K in 1 bar hydrogen leads to a substantial reduction of the bulk structure and yields a mixture of SnO2 and metallic β-Sn. On the powder catalyst this transformation is fully reversible upon oxidation in 1 bar O2 at 673 K. Strongly reduced thin films, however, can only be re-transformed to SnO2 if the reduction temperature did not exceed 573 K. For GeO2, the situation is more complex due to its polymorphism. Whereas the tetragonal phase is structurally stable during reduction, oxidation or catalytic reaction, a small part of the hexagonal phase is always transformed into the tetragonal at 673 K independent of the gas phase used. SnO2 is highly active and CO2 selective in methanol steam reforming, but the initial high activity drops considerably upon reduction between 373 and 573 K and almost complete catalyst deactivation is observed after reduction at 673 K, which is associated with the parallel formation of β-Sn. In close correlation to the structural results, the catalytic activity and selectivity can be restored upon an oxidative catalyst regeneration at 673 K. Tetragonal GeO2 exhibits only a small activity and no pronounced selectivity to either CO or CO2, at least after reduction. In its fully oxidized state release of surface/lattice oxygen results in a non-catalytic formation of CO2 by oxidation of CO originating from catalytic dehydrogenation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.339
Times cited: 20
DOI: 10.1016/j.apcata.2009.12.027
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“Rapid microwave-assisted synthesis of benzene bridged periodic mesoporous organosilicas”. Smeulders G, Meynen V, van Baelen G, Mertens M, Lebedev OI, Van Tendeloo G, Maes BUW, Cool P, Journal of materials chemistry 19, 3042 (2009). http://doi.org/10.1039/b820792e
Abstract: Following extended use in organic chemistry, microwave-assisted synthesis is gaining more importance in the field of inorganic chemistry, especially for the synthesis of nanoporous materials. It offers some major advantages such as a significant shortening of the synthesis time and an improved promotion of nucleation. In the research here reported, microwave technology is applied for the synthesis of benzene bridged PMOs (periodic mesoporous organosilicas). PMOs are one of the latest innovations in the field of hybrid ordered mesoporous materials and have attracted much attention because of their feasibility in electronics, catalysis, separation and sorption applications. The different synthesis steps (stirring, aging and extraction) of the classical PMO synthesis are replaced by microwave-assisted synthesis steps. The characteristics of the as-synthesized materials are evaluated by X-ray diffraction, N2-sorption, thermogravimetric analysis, scanning- and transmission electron microscopy. The microwave-assisted synthesis drastically reduces the synthesis time by more than 40 hours without any loss in structural properties, such as mesoscale and molecular ordering. The porosity of the PMO materials has even been improved by more than 25%. Moreover, the number of handling/transfer steps and amounts of chemicals and waste are drastically reduced. The study also shows that there is a clear time (1 to 3 hours) and temperature frame (373 K to 403 K) wherein synthesis of benzene bridged PMO is optimal. In conclusion, the microwave-assisted synthesis pathway allows an improved material to be obtained in a more economical way i.e. a much shorter time with fewer chemicals and less waste.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Times cited: 20
DOI: 10.1039/b820792e
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“The ferroelectric phase transition in tridymite type BaAl2O4 studied by electron microscopy”. Abakumov AM, Lebedev OI, Nistor L, Van Tendeloo G, Amelinckx S, Phase transitions 71, 143 (2000). http://doi.org/10.1080/01411590008224545
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.06
Times cited: 21
DOI: 10.1080/01411590008224545
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“Mesoporous material formed by acidic hydrothermal assembly of silicalite-1 precursor nanoparticles in the absence of meso-templates”. Stevens WJJ, Meynen V, Bruijn E, Lebedev OI, Van Tendeloo G, Cool P, Vansant EF, Microporous and mesoporous materials: zeolites, clays, carbons and related materials 110, 77 (2008). http://doi.org/10.1016/j.micromeso.2007.09.007
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.615
Times cited: 21
DOI: 10.1016/j.micromeso.2007.09.007
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“Post-synthesis deposition of V-Zeolitic nanoparticles in SBA-15”. Meynen V, Beyers E, Cool P, Vansant EF, Mertens M, Weyten H, Lebedev OI, Van Tendeloo G, Chemical communications , 898 (2004). http://doi.org/10.1039/b400636d
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 6.319
Times cited: 22
DOI: 10.1039/b400636d
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“Structural characterization and luminescence properties of nanostructured lanthanide-doped Sc2O3 prepared by propellant synthesis”. Krsmanovic R, Lebedev OI, Speghini A, Bettinelli M, Polizzi S, Van Tendeloo G, Nanotechnology 17, 2805 (2006). http://doi.org/10.1088/0957-4484/17/11/013
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 22
DOI: 10.1088/0957-4484/17/11/013
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“Structure and properties of artificial [(La0.7Sr0.3MnO3)m(SrTiO3)n]15 superlattices on (001)SrTiO3”. Lebedev OI, Verbeeck J, Van Tendeloo G, Dubourdieu C, Rosina M, Chaudouët P, Journal of applied physics 94, 7646 (2003). http://doi.org/10.1063/1.1628407
Abstract: Complex [(La0.7Sr0.3MnO3)(m)(SrTiO3)(n)] [(LSMO)(m)/(STO)(8)](15) superlattices with different layer thicknesses (m=5, 8, 12, 16, 32) have been prepared using pulsed liquid injection metalorganic chemical vapor deposition. Transmission electron microscopy and electron diffraction reveal a very clear and well-separated layer sequence. The remarkable microstructure, as well as the ferromagnetic transition temperature, depends on the LSMO layer thickness. Apart from a very clear layer sequence, electron microscopy shows evidence of a self-assembled nanostructure formation: SrMnO3 nanoinclusions and associated SrTiO3-SrMnO3 thin walls. A formation model and growth mechanism for the self-assembled structure is proposed, based on high resolution and energy filtered elemental imaging. (C) 2003 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 22
DOI: 10.1063/1.1628407
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“Deposition of vanadium silicalite-1 nanoparticles on SBA-15 materials: structural and transport characteristics of SBA-VS-15”. Meynen V, Cool P, Vansant EF, Kortunov P, Grinberg F, Kärger J, Mertens M, Lebedev OI, Van Tendeloo G, Microporous and mesoporous materials 99, 14 (2007). http://doi.org/10.1016/j.micromeso.2006.08.029
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.615
Times cited: 23
DOI: 10.1016/j.micromeso.2006.08.029
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“Fluorine doped Fe2O3 nanostructures by a one-pot plasma-assisted strategy”. Carraro G, Gasparotto A, Maccato C, Bontempi E, Lebedev OI, Turner S, Sada C, Depero LE, Van Tendeloo G, Barreca D, RSC advances 3, 23762 (2013). http://doi.org/10.1039/c3ra43775b
Abstract: The present work reports on the synthesis of fluorine doped Fe2O3 nanomaterials by a single-step plasma enhanced-chemical vapor deposition (PE-CVD) strategy. In particular, Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N′,N′-tetramethylethylenediamine) was used as molecular source for both Fe and F in Ar/O2 plasmas. The structure, morphology and chemical composition of the synthesized nanosystems were thoroughly analyzed by two-dimensional X-ray diffraction (XRD2), field emission-scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM). A suitable choice of processing parameters enabled the selective formation of α-Fe2O3 nanomaterials, characterized by an homogeneous F doping, even at 100 °C. Interestingly, a simultaneous control of the system nanoscale organization and fluorine content could be achieved by varying the sole growth temperature. The tailored properties of the resulting materials can be favourably exploited for several technological applications, ranging from photocatalysis, to photoelectrochemical cells and gas sensing.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 23
DOI: 10.1039/c3ra43775b
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“Influence of the Ar/O2 ratio on the growth and biaxial alignment of yttria stabilized zirconia layers during reactive unbalanced magnetron sputtering”. Mahieu S, Ghekiere P, de Winter G, Depla D, de Gryse R, Lebedev OI, Van Tendeloo G, Thin solid films : an international journal on the science and technology of thin and thick films 484, 18 (2005). http://doi.org/10.1016/j.tsf.2005.01.021
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.879
Times cited: 23
DOI: 10.1016/j.tsf.2005.01.021
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“Leached natural saponite as the silicate source in the synthesis of aluminosilicate hexagonal mesoporous materials”. Linssen T, Cool P, Baroudi M, Cassiers K, Vansant EF, Lebedev O, van Landuyt J, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 106, 4470 (2002). http://doi.org/10.1021/jp015578p
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.177
Times cited: 23
DOI: 10.1021/jp015578p
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“Phase transition and magnetic anisotropy of (La,Sr)MnO3 thin films”. Wang Z-H, Kronmüller H, Lebedev OI, Gross GM, Razavi FS, Habermeier HU, Shen BG, Physical review : B : condensed matter and materials physics 65, 054411 (2002). http://doi.org/10.1103/PhysRevB.65.054411
Abstract: The magnetic proper-ties and their correlation with the microstructure and electrical transport are investigated in La0.88Sr0.1MnO3 films grown on (100)SrTiO3 Single crystal substrates with thickness ranging from 100 to 2500 Angstrom. The ultrathin film (t = 100 Angstrom) has a single ferromagnetic transition (FMT) at T-c of 250 K, whereas the thicker films exhibit two FMTs, with the main one at a lowered T-c of 200 K while the minor one around 300 K. Furthermore, a thickness dependent magnetic anisotropy has been found, strongly indicating the existence of strain effect, which is also revealed by the transmission electron microscopy study. The suppressed Jahn-Teller distortion (JTD) by the epitaxial strain, and the recovered JTD due to the strain relexation are suggested to explain the metallic behavior in thin films and the insulating behavior in the thick film (t = 2500 Angstrom), repectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 23
DOI: 10.1103/PhysRevB.65.054411
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“Light-assisted nucleation of silver nanowires during polyol synthesis”. Lin H, Ohta T, Paul A, Hutchison JA, Kirilenko D, Lebedev O, Van Tendeloo G, Hofkens J, Uji-i H, Journal of photochemistry and photobiology: A: chemistry 221, 220 (2011). http://doi.org/10.1016/j.jphotochem.2011.04.015
Abstract: This report describes the effect of light irradiation on the synthesis of silver nanowires by the well-known polyol method. High quality nanowires are produced in high yields when the reaction suspension is irradiated with 400500 nm light during the nucleation stage. These studies suggest that light accelerates the formation of the nanoparticle seeds most appropriate for nanowire growth.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.625
Times cited: 24
DOI: 10.1016/j.jphotochem.2011.04.015
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“Multi-step loading of titania on mesoporous silica: influence of the morphology and the porosity on the catalytic degradation of aqueous pollutants and VOC's”. de Witte K, Meynen V, Mertens M, Lebedev OI, Van Tendeloo G, Sepúlveda-Escribano A, Rodríguez-Reinoso F, Vansant EF, Cool P, Applied catalysis : B : environmental 84, 125 (2008). http://doi.org/10.1016/j.apcatb.2008.03.015
Abstract: Titania nanoparticles have been deposited on inert porous silica supports with high specific surface area. These materials have potential applications in paint and textile industry as the titania particles selectively deposited on the inner surface of the silica supports act as a photocatalyst. The inert external surface is necessary to avoid photodegradation of the textile material or the paint components. The photocatalytic activity of the catalysts has been evaluated with two catalytic setups. One setup in aqueous phase, for the degradation of dyes such as rhodamine-6G, is commonly used. The second setup is a continuous flow gaseous phase setup which was used for the mineralization of ethanol as a representative volatile organic compound (VOC). The influence of the porosity and the morphology of the silica supports on the photocatalytic activity are discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 9.446
Times cited: 24
DOI: 10.1016/j.apcatb.2008.03.015
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“Selectivity in sorption and hydrogenation of methyl oleate and elaidate on MFI zeolites”. Philippaerts A, Paulussen S, Turner S, Lebedev OI, Van Tendeloo G, Poelman H, Bulut M, de Clippel F, Smeets P, Sels B, Jacobs P, Journal of catalysis 270, 172 (2010). http://doi.org/10.1016/j.jcat.2009.12.022
Abstract: Different zeolites were tested for selective removal of methyl elaidate (trans isomer) from an equimolar mixture with methyl oleate (cis isomer). Sorption experiments of the geometric isomers show that only ZSM-5 samples with reduced Al content in the framework are able to discriminate among the bent cis and the linear trans fatty acid methyl esters. Hydrogenation experiments of equimolar methyl oleate and elaidate mixtures at low temperature (65 °C) and high hydrogen pressure (6.0 MPa), using Pt catalysts, confirm this result. Only with a Pt/NaZSM-5 catalyst outspoken selectivity for the hydrogenation of the trans isomer is obtained. In order to prepare a selective Pt/ZSM-5 catalyst, the influence of Pt addition (impregnation, ion-exchange and competitive ion-exchange) and Pt activation (different calcination and reduction temperatures) on the Pt-distribution and Pt particle size was investigated using SEM, bright-field and HR TEM, EDX, electron tomography, CO-chemisorption, XPS, XRD, and UVvis measurements. The best result in terms of hydrogenation activity and selectivity is obtained with a Pt/ZSM-5 catalyst, which is prepared via competitive ion-exchange, followed by slow calcination up to 350 °C under high O2 flow and a reduction up to 500 °C under H2. This preparation method leads to a Pt/ZSM-5 catalyst with the best Pt distribution and the smallest Pt clusters occluded in the zeolite structure. Finally, the influence of zeolite crystal size, morphology, and elemental composition of ZSM-5 on hydrogenation activity and selectivity was investigated in detail.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 24
DOI: 10.1016/j.jcat.2009.12.022
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“Phase selection enabled formation of abrupt axial heterojunctions in branched oxide nanowires”. Gao J, Lebedev OI, Turner S, Li YF, Lu YH, Feng YP, Boullay P, Prellier W, Van Tendeloo G, Wu T, Nano letters 12, 275 (2012). http://doi.org/10.1021/nl2035089
Abstract: Rational synthesis of nanowires via the vaporliquidsolid (VLS) mechanism with compositional and structural controls is vitally important for fabricating functional nanodevices from bottom up. Here, we show that branched indium tin oxide nanowires can be in situ seeded in vapor transport growth using tailored AuCu alloys as catalyst. Furthermore, we demonstrate that VLS synthesis gives unprecedented freedom to navigate the ternary InSnO phase diagram, and a rare and bulk-unstable cubic phase can be selectively stabilized in nanowires. The stabilized cubic fluorite phase possesses an unusual almost equimolar concentration of In and Sn, forming a defect-free epitaxial interface with the conventional bixbyite phase of tin-doped indium oxide that is the most employed transparent conducting oxide. This rational methodology of selecting phases and making abrupt axial heterojunctions in nanowires presents advantages over the conventional synthesis routes, promising novel composition-modulated nanomaterials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 12.712
Times cited: 25
DOI: 10.1021/nl2035089
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“Controlled formation of amine-templated mesostructured zirconia with remarkably high thermal stability”. Cassiers K, Linssen T, Aerts K, Cool P, Lebedev O, Van Tendeloo G, van Grieken R, Vansant EF, Journal of materials chemistry 13, 3033 (2003). http://doi.org/10.1039/b310200a
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 26
DOI: 10.1039/b310200a
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“From spin induced ferroelectricity to dipolar glasses : spinel chromites and mixed delafossites”. Maignan A, Martin C, Singh K, Simon C, Lebedev OI, Turner S, Journal of solid state chemistry 195, 41 (2012). http://doi.org/10.1016/j.jssc.2012.01.063
Abstract: Magnetoelectric multiferroics showing coupling between polarization and magnetic order are attracting much attention. For instance, they could be used in memory devices. Metal-transition oxides are provided several examples of inorganic magnetoelectric multiferroics. In the present short review, spinel and delafossite chromites are described. For the former, an electric polarization is evidenced in the ferrimagnetic state for ACr2O4 polycrystalline samples (A=Ni, Fe, Co). The presence of a JahnTeller cation such as Ni2+ at the A site is shown to yield larger polarization values. In the delafossites, substitution by V3+ at the Cr or Fe site in CuCrO2 (CuFeO2) suppresses the complex antiferromagnetic structure at the benefit of a spin glass state. The presence of cation disorder, probed by transmission electron microscopy, favors relaxor-like ferroelectricity. The results on the ferroelectricity of ferrimagnets and insulating spin glasses demonstrate that, in this research field, transition-metal oxides are worth to be studied.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 27
DOI: 10.1016/j.jssc.2012.01.063
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“In situ HREM irradiation study of point-defect clustering in MBE-grown strained Si1-xGex/(001)Si structures”. Fedina L, Lebedev OI, Van Tendeloo G, van Landuyt J, Mironov OA, Parker EHC, Physical review : B : condensed matter and materials physics 61, 10336 (2000). http://doi.org/10.1103/PhysRevB.61.10336
Abstract: We present a detailed analysis of the point-defect clustering in strained Si/Si(1-x)Ge(x)/(001)Si structures, including the interaction of the point defects with the strained interfaces and the sample surface during 400 kV electron irradiation at room temperature. Point-defect cluster formation is very sensitive to the type and magnitude of the strain in the Si and Si(1-x)Ge(x) layers. A small compressive strain (-0.3%) in the SiGe alloy causes an aggregation of vacancies in the form of metastable [110]-oriented chains. They are located on {113} planes and further recombine with interstitials. Tensile strain in the Si layer causes an aggregation of interstitial atoms in the forms of additional [110] rows which are inserted on {113} planes with [001]-split configurations. The chainlike configurations are characterized by a large outward lattice relaxation for interstitial rows (0.13 +/-0.01 nm) and a very small inward relaxation for vacancy chains (0.02+/-0.01 nm). A compressive strain higher than -0.5% strongly decreases point-defect generation inside the strained SiGe alloy due to the large positive value of the formation volume of a Frenkel pair. This leads to the suppression of point-defect clustering in a strained SiGe alloy so that SiGe relaxes via a diffusion of vacancies from the Si layer, giving rise to an intermixing at the Si/SiGe interface. In material with a 0.9% misfit a strongly increased flow of vacancies from the Si layer to the SiGe layer and an increased biaxial strain in SiGe bath promote the preferential aggregation of vacancies in the (001) plane, which relaxes to form intrinsic 60 degrees dislocation loops.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.61.10336
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