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Author Rehor, I.; Mackova, H.; Filippov, S.K.; Kucka, J.; Proks, V.; Slegerova, J.; Turner, S.; Van Tendeloo, G.; Ledvina, M.; Hruby, M.; Cigler, P.;
Title Fluorescent nanodiamonds with bioorthogonally reactive protein-resistant polymeric coatings Type A1 Journal article
Year 2014 Publication ChemPlusChem Abbreviated Journal Chempluschem
Volume 79 Issue 1 Pages 21-24
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The novel synthesis of a polymeric interface grown from the surface of bright fluorescent nanodiamonds is reported. The polymer enables bioorthogonal attachment of various molecules by click chemistry; the particles are resistant to nonspecific protein adsorption and show outstanding colloidal stability in buffers and biological media. The coating fully preserves the unique optical properties of the nitrogen-vacancy centers that are crucial for bioimaging and sensoric applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000337974900002 Publication Date 2013-12-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2192-6506; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.797 Times cited 34 Open Access
Notes (down) EU 7FP Program (no.262348); European Soft Matter Infrastructure; ESMI; ERC (grant no.246791)-COUNTATOMS; FWO Approved Most recent IF: 2.797; 2014 IF: 2.997
Call Number UA @ lucian @ c:irua:113088 Serial 1235
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Author Lubk, A.; Guzzinati, G.; Börrnert, F.; Verbeeck, J.
Title Transport of intensity phase retrieval of arbitrary wave fields including vortices Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 111 Issue 17 Pages 173902-173905
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The phase problem can be considered as one of the cornerstones of quantum mechanics intimately connected to the detection process and the uncertainty relation. The latter impose fundamental limits on the manifold phase reconstruction schemes invented to date, in particular, at small magnitudes of the quantum wave. Here, we show that a rigorous solution of the transport of intensity reconstruction (TIE) scheme in terms of a linear elliptic partial differential equation for the phase provides reconstructions even in the presence of wave zeros if particular boundary conditions are given. We furthermore discuss how partial coherence hampers phase reconstruction and show that a modified version of the TIE reconstructs the curl-free current density at arbitrary (in)coherence. Our results open the way for TIE-based phase retrieval of arbitrary wave fields, eventually containing zeros such as phase vortices.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000326148400006 Publication Date 2013-10-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 40 Open Access
Notes (down) Esteem2; Vortex; esteem2ta ECASJO; Approved Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:111093 Serial 3726
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Author Tan, H.; Tian, H.; Verbeeck, J.; Janssens, K.; Van Tendeloo, G.
Title Nanoscale investigation of the degradation mechanism of a historical chrome yellow paint by quantitative electron energy loss spectroscopy mapping of chromium species Type A1 Journal article
Year 2013 Publication Angewandte Chemie: international edition in English Abbreviated Journal Angew Chem Int Edit
Volume 52 Issue 43 Pages 11360-11363
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Getting the picture: The investigation of 100 year old chrome yellow paint by transmission electron microscopy and spectroscopy has led to the identification of four types of coreshell particles. This nanoscale investigation has allowed a mechanism to be proposed for the darkening of some bright yellow colors in Van Gogh's paintings (e.g. in Falling leaves (Les Alyscamps), 1888).
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000330735800026 Publication Date 2013-09-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1433-7851; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 11.994 Times cited 29 Open Access
Notes (down) Esteem2; Vortex; Countatoms; esteem2jra3 ECASJO; Approved Most recent IF: 11.994; 2013 IF: 11.336
Call Number UA @ lucian @ c:irua:110947UA @ admin @ c:irua:110947 Serial 2266
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Author Heidari, H.; van den Broek, W.; Bals, S.
Title Quantitative electron tomography : the effect of the three-dimensional point spread function Type A1 Journal article
Year 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 135 Issue Pages 1-5
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000326941500001 Publication Date 2013-06-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 6 Open Access
Notes (down) Esteem2; Sunflower; esteem2_jra4 Approved Most recent IF: 2.843; 2013 IF: 2.745
Call Number UA @ lucian @ c:irua:111397 Serial 2756
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Author Wang, Z.-H.; Lebedev, O.I.; Van Tendeloo, G.; Cristiani, G.; Habermeier, H.-U.
Title Crosshatching on La0.5Ca0.5MnO3 ultrathin films epitaxially grown on SrTiO3(100) Type A1 Journal article
Year 2008 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 77 Issue 11 Pages 1-5
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The morphological evolution in La(0.5)Ca(0.5)MnO(3)/SrTiO(3)(100) ultrathin films has been revealed by atomic force microscopy. It was found that ordered linear defects, which are in 1-2 unit cells high and oriented along the cubic [110] and [100] directions, first appear on the smooth surface of films with a thickness of 10 nm. As the epitaxial growth proceeds, these lines on surface develop into a crosshatch pattern for films with a thickness of 25 nm. Using the results of transmission electron microscopy and electrical measurements, we discuss the interplay between the surface pattern formation, the internal dislocation structure, and the variations in the electrical properties.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000254542800126 Publication Date 2008-03-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 8 Open Access
Notes (down) ESTEEM nr 026019 Approved Most recent IF: 3.836; 2008 IF: 3.322
Call Number UA @ lucian @ c:irua:70022 Serial 548
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Author Ke, X.; Bals, S.; Romo Negreira, A.; Hantschel, T.; Bender, H.; Van Tendeloo, G.
Title TEM sample preparation by FIB for carbon nanotube interconnects Type A1 Journal article
Year 2009 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 109 Issue 11 Pages 1353-1359
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A powerful method to study carbon nanotubes (CNTs) grown in patterned substrates for potential interconnects applications is transmission electron microscopy (TEM). However, high-quality TEM samples are necessary for such a study. Here, TEM specimen preparation by focused ion beam (FIB) has been used to obtain lamellae of patterned samples containing CNTs grown inside contact holes. A dual-cap Pt protection layer and an extensive 5 kV cleaning procedure are applied in order to preserve the CNTs and avoid deterioration during milling. TEM results show that the inner shell structure of the carbon nanotubes has been preserved, which proves that focused ion beam is a useful technique to prepare TEM samples of CNT interconnects.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000270765800006 Publication Date 2009-07-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 21 Open Access
Notes (down) Esteem 026019; Iap Approved Most recent IF: 2.843; 2009 IF: 2.067
Call Number UA @ lucian @ c:irua:79074 Serial 3485
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Author Ke, X.; Bals, S.; Cott, D.; Hantschel, T.; Bender, H.; Van Tendeloo, G.
Title Three-dimensional analysis of carbon nanotube networks in interconnects by electron tomography without missing wedge artifacts Type A1 Journal article
Year 2010 Publication Microscopy and microanalysis Abbreviated Journal Microsc Microanal
Volume 16 Issue 2 Pages 210-217
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The three-dimensional (3D) distribution of carbon nanotubes (CNTs) grown inside semiconductor contact holes is studied by electron tomography. The use of a specialized tomography holder results in an angular tilt range of ±90°, which means that the so-called missing wedge is absent. The transmission electron microscopy (TEM) sample for this purpose consists of a micropillar that is prepared by a dedicated procedure using the focused ion beam (FIB) but keeping the CNTs intact. The 3D results are combined with energy dispersive X-ray spectroscopy (EDS) to study the relation between the CNTs and the catalyst particles used during their growth. The reconstruction, based on the full range of tilt angles, is compared with a reconstruction where a missing wedge is present. This clearly illustates that the missing wedge will lead to an unreliable interpretation and will limit quantitative studies
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge, Mass. Editor
Language Wos 000276137200011 Publication Date 2010-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1431-9276;1435-8115; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.891 Times cited 42 Open Access
Notes (down) Esteem 026019; Fwo; Iap-Vi Approved Most recent IF: 1.891; 2010 IF: 3.259
Call Number UA @ lucian @ c:irua:82279 Serial 3642
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Author Verbeeck, J.; Bertoni, G.
Title Model-based quantification of EELS: is standardless quantification possible? Type A1 Journal article
Year 2008 Publication Microchimica acta Abbreviated Journal Microchim Acta
Volume 161 Issue 3/4 Pages 439-443
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electron energy loss spectroscopy (EELS) is an ideal tool to obtain chemical information from nanoscale volumes. Quantification of the experimental spectra however has prevented for a long time access to the available information in a reliable and reproducible way. We present recent advances in model-based quantification of EELS spectra and show that we obtain the best possible precision for a given dataset, as well as remarkably good accuracies when applied to three different materials. The results are shown to be far superior over conventional quantification techniques and could hold a promise for standardless quantification of EELS spectra.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000256175600024 Publication Date 2008-02-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0026-3672;1436-5073; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.58 Times cited 5 Open Access
Notes (down) Esteem 026019; Fwo; G.0425.05; Iap V; Goa 2005 Approved Most recent IF: 4.58; 2008 IF: 1.910
Call Number UA @ lucian @ c:irua:69292UA @ admin @ c:irua:69292 Serial 2100
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Author Tan, H.; Turner, S.; Yücelen, E.; Verbeeck, J.; Van Tendeloo, G.
Title 2D atomic mapping of oxidation states in transition metal oxides by scanning transmission electron microscopy and electron energy-loss spectroscopy Type A1 Journal article
Year 2011 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 107 Issue 10 Pages 107602
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Using a combination of high-angle annular dark-field scanning transmission electron microscopy and atomically resolved electron energy-loss spectroscopy in an aberration-corrected transmission electron microscope we demonstrate the possibility of 2D atom by atom valence mapping in the mixed valence compound Mn3O4. The Mn L2,3 energy-loss near-edge structures from Mn2+ and Mn3+ cation sites are similar to those of MnO and Mn2O3 references. Comparison with simulations shows that even though a local interpretation is valid here, intermixing of the inelastic signal plays a significant role. This type of experiment should be applicable to challenging topics in materials science, such as the investigation of charge ordering or single atom column oxidation states in, e.g., dislocations.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000294406600018 Publication Date 2011-09-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 115 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 8.462; 2011 IF: 7.370
Call Number UA @ lucian @ c:irua:91265 c:irua:91265 c:irua:91265UA @ admin @ c:irua:91265 Serial 5
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Author Molina, L.; Tan, H.; Biermans, E.; Batenburg, K.J.; Verbeeck, J.; Bals, S.; Van Tendeloo, G.
Title Barrier efficiency of sponge-like La2Zr2O7 buffer layers for YBCO-coated conductors Type A1 Journal article
Year 2011 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 24 Issue 6 Pages 065019-065019,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Solution derived La2Zr2O7 films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La2Zr2O7, but different film processing methods can yield similar microstructural features such as nanovoids and nanometer-sized La2Zr2O7 grains. Nanoporosity is a typical feature found in such films and the implications for the functionality of the films are investigated by a combination of scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) and quantitative electron tomography. Chemical solution based La2Zr2O7 films deposited on flexible Ni5 at.%W substrates with a {100}lang001rang biaxial texture were prepared for an in-depth characterization. A sponge-like structure composed of nanometer-sized voids is revealed by high-angle annular dark-field scanning transmission electron microscopy in combination with electron tomography. A three-dimensional quantification of nanovoids in the La2Zr2O7 film is obtained on a local scale. Mostly non-interconnected highly faceted nanovoids compromise more than one-fifth of the investigated sample volume. The diffusion barrier efficiency of a 170 nm thick La2Zr2O7 film is investigated by STEM-EELS, yielding a 1.8 ± 0.2 nm oxide layer beyond which no significant nickel diffusion can be detected and intermixing is observed. This is of particular significance for the functionality of YBa2Cu3O7 − δ coated conductor architectures based on solution derived La2Zr2O7 films as diffusion barriers.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000290472900021 Publication Date 2011-04-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.878 Times cited 31 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 2.878; 2011 IF: 2.662
Call Number UA @ lucian @ c:irua:88639UA @ admin @ c:irua:88639 Serial 221
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Author Ray, S.; Kolen'ko, Y.V.; Kovnir, K.A.; Lebedev, O.I.; Turner, S.; Chakraborty, T.; Erni, R.; Watanabe, T.; Van Tendeloo, G.; Yoshimura, M.; Itoh, M.
Title Defect controlled room temperature ferromagnetism in Co-doped barium titanate nanocrystals Type A1 Journal article
Year 2012 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 23 Issue 2 Pages 025702,1-025702,10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
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)}
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000298409000011 Publication Date 2011-12-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited 19 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 3.44; 2012 IF: 3.842
Call Number UA @ lucian @ c:irua:93636 Serial 614
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Author Verbeeck, J.; Bals, S.; Lamoen, D.; Luysberg, M.; Huijben, M.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H.; Blank, D.H.A.; Van Tendeloo, G.
Title Electronic reconstruction at n-type SrTiO3/LaAlO3 interfaces Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 8 Pages 085113,1-085113,6
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electron-energy-loss spectroscopy (EELS) is used to investigate single layers of LaAlO3 grown on SrTiO3 having an n-type interface as well as multilayers of LaAlO3 and SrTiO3 in which both n- and p-type interfaces occur. Only minor changes in Ti valence at the n-type interface are observed. This finding seems to contradict earlier experiments for other SrTiO3/LaAlO3 systems where large deviations in Ti valency were assumed to be responsible for the conductivity of these interfaces. Ab initio calculations have been carried out in order to interpret our EELS results. Using the concept of Bader charges, it is demonstrated that the so-called polar discontinuity is mainly resolved by lattice distortions and to a far lesser extent by changes in valency for both single layer and multilayer geometries.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000275053300040 Publication Date 2010-02-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 25 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:81768UA @ admin @ c:irua:81768 Serial 1005
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Author Figuerola, A.; Franchini, I.R.; Fiore, A.; Mastria, R.; Falqui, A.; Bertoni, G.; Bals, S.; Van Tendeloo, G.; Kudera, S.; Cingolani, R.; Manna, L.
Title End-to-end assembly of shape-controlled nanocrystals via a nanowelding approach mediated by gold domains Type A1 Journal article
Year 2009 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 21 Issue 5 Pages 550-554
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Welding nanocrystals for assembly: The welding of Au domains grown on the tips of shape-controlled cadmium chalcogenide colloidal nanocrystals is used as a strategy for their assembly. Iodine-induced coagulation of selectively grown Au domains leads to assemblies such as flowerlike structures based on bullet-shaped nanocrystals, linear and cross-linked chains of nanorods, and globular networks with tetrapods as building blocks.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000263371800005 Publication Date 2008-11-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 110 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 19.791; 2009 IF: 8.379
Call Number UA @ lucian @ c:irua:75960 Serial 1037
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Author Shenderova, O.A.; Vlasov, I.I.; Turner, S.; Van Tendeloo, G.; Orlinskii, S.B.; Shiryaev, A.A.; Khomich, A.A.; Sulyanov, S.N.; Jelezko, F.; Wrachtrup, J.
Title Nitrogen control in nanodiamond produced by detonation shock-wave-assisted synthesis Type A1 Journal article
Year 2011 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 115 Issue 29 Pages 14014-14024
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Development of efficient production methods of nanodiamond (ND) particles containing substitutional nitrogen and nitrogen-vacancy (NV) complexes remains an important goal in the nanodiamond community. ND synthesized from explosives is generally not among the preferred candidates for imaging applications owing to lack of optically active particles containing NV centers. In this paper, we have systematically studied representative classes of NDs produced by detonation shock wave conversion of different carbon precursor materials, namely, graphite and a graphite/hexogen mixture into ND, as well as ND produced from different combinations of explosives using different cooling methods (wet or dry cooling). We demonstrate that (i) the N content in nanodiamond particles can be controlled through a correct selection of the carbon precursor material (addition of graphite, explosives composition); (ii) particles larger than approximately 20 nm may contain in situ produced optically active NV centers, and (iii) in ND produced from explosives, NV centers are detected only in ND produced by wet synthesis. ND synthesized from a mixture of graphite/explosive contains the largest amount of NV centers formed during synthesis and thus deserves special attention.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000292892500009 Publication Date 2011-06-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 54 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 4.536; 2011 IF: 4.805
Call Number UA @ lucian @ c:irua:91259 Serial 2342
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Author Simon, Q.; Barreca, D.; Bekermann, D.; Gasparotto, A.; Maccato, C.; Comini, E.; Gombac, V.; Fornasiero, P.; Lebedev, O.I.; Turner, S.; Devi, A.; Fischer, R.A.; Van Tendeloo, G.
Title Plasma-assisted synthesis of Ag/ZnO nanocomposites : first example of photo-induced H2 production and sensing Type A1 Journal article
Year 2011 Publication International journal of hydrogen energy Abbreviated Journal Int J Hydrogen Energ
Volume 36 Issue 24 Pages 15527-15537
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Ag/ZnO nanocomposites were developed by a plasma-assisted approach. The adopted strategy exploits the advantages of Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) for the growth of columnar ZnO arrays on Si(100) and Al2O3 substrates, in synergy with the infiltration power of the Radio Frequency (RF)-sputtering technique for the subsequent dispersion of different amounts of Ag nanoparticles (NPs). The resulting composites, both as-prepared and after annealing in air, were thoroughly characterized with particular attention on their morphological organization, structure and composition. For the first time, the above systems have been used as catalysts in the production of hydrogen by photo-reforming of alcoholic solutions, yielding a stable H2 evolution even by the sole use of simulated solar radiation. In addition, Ag/ZnO nanocomposites presented an excellent response in the gas-phase detection of H2, opening attractive perspectives for advanced technological applications.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000297089700006 Publication Date 2011-10-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0360-3199; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.582 Times cited 62 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 3.582; 2011 IF: 4.054
Call Number UA @ lucian @ c:irua:91901 Serial 2627
Permanent link to this record
 

 
Author Heidari Mezerji, H.; van den Broek, W.; Bals, S.
Title A practical method to determine the effective resolution in incoherent experimental electron tomography Type A1 Journal article
Year 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 5 Pages 330-336
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract It is not straightforward to determine resolution for a 3D reconstruction when performing an electron tomography experiment. Different contributions such as missing wedge and misalignment add up and often influence the final resolution in an anisotropic manner. The conventional resolution measures can not be used for all of the reconstruction techniques, especially for iterative techniques which are more commonly used for electron tomography in materials science. Here we define a quantitative resolution measure that determines the resolution in three orthogonal directions of the reconstruction. As an application we use this measure to determine the optimum number of simultaneous iterative reconstruction technique (SIRT) iterations to reconstruct the gold nanoparticles, based on a high angle annular dark field STEM (HAADF-STEM) tilt series.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000289396900005 Publication Date 2011-01-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 26 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:87606 Serial 2688
Permanent link to this record
 

 
Author Verbeeck, J.; Tian, H.; Schattschneider, P.
Title Production and application of electron vortex beams Type A1 Journal article
Year 2010 Publication Nature Abbreviated Journal Nature
Volume 467 Issue 7313 Pages 301-304
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Vortex beams (also known as beams with a phase singularity) consist of spiralling wavefronts that give rise to angular momentum around the propagation direction. Vortex photon beams are widely used in applications such as optical tweezers to manipulate micrometre-sized particles and in micro-motors to provide angular momentum1, 2, improving channel capacity in optical3 and radio-wave4 information transfer, astrophysics5 and so on6. Very recently, an experimental realization of vortex beams formed of electrons was demonstrated7. Here we describe the creation of vortex electron beams, making use of a versatile holographic reconstruction technique in a transmission electron microscope. This technique is a reproducible method of creating vortex electron beams in a conventional electron microscope. We demonstrate how they may be used in electron energy-loss spectroscopy to detect the magnetic state of materials and describe their properties. Our results show that electron vortex beams hold promise for new applications, in particular for analysing and manipulating nanomaterials, and can be easily produced.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000281824900033 Publication Date 2010-09-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836;1476-4687; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 40.137 Times cited 626 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 40.137; 2010 IF: 36.104
Call Number UA @ lucian @ c:irua:84878UA @ admin @ c:irua:84878 Serial 2720
Permanent link to this record
 

 
Author Abakumov, A.M.; Hadermann, J.; Batuk, M.; d' Hondt, H.; Tyablikov, O.A.; Rozova, M.G.; Pokholok, K.V.; Filimonov, D.S.; Sheptyakov, D.V.; Tsirlin, A.A.; Niermann, D.; Hemberger, J.; Van Tendeloo, G.; Antipov, E.V.
Title Slicing the Perovskite structure with crystallographic shear planes : the AnBnO3n-2 homologous series Type A1 Journal article
Year 2010 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 49 Issue 20 Pages 9508-9516
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A new AnBnO3n−2 homologous series of anion-deficient perovskites has been evidenced by preparation of the members with n = 5 (Pb2.9Ba2.1Fe4TiO13) and n = 6 (Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16) in a single phase form. The crystal structures of these compounds were determined using a combination of transmission electron microscopy and X-ray and neutron powder diffraction (S.G. Ammm, a = 5.74313(7), b = 3.98402(4), c = 26.8378(4) Å, RI = 0.035, RP = 0.042 for Pb2.9Ba2.1Fe4TiO13 and S.G. Imma, a = 5.7199(1), b = 3.97066(7), c = 32.5245(8) Å, RI = 0.032, RP = 0.037 for Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16). The crystal structures of the AnBnO3n−2 homologues are formed by slicing the perovskite structure with (01)p crystallographic shear (CS) planes. The shear planes remove a layer of oxygen atoms and displace the perovskite blocks with respect to each other by the 1/2[110]p vector. The CS planes introduce edge-sharing connections of the transition metal−oxygen polyhedra at the interface between the perovskite blocks. This results in intrinsically frustrated magnetic couplings between the perovskite blocks due to a competition of the exchange interactions between the edge- and the corner-sharing metal−oxygen polyhedra. Despite the magnetic frustration, neutron powder diffraction and Mssbauer spectroscopy reveal that Pb2.9Ba2.1Fe4TiO13 and Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16 are antiferromagnetically ordered below TN = 407 and 343 K, respectively. The Pb2.9Ba2.1Fe4TiO13 and Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16 compounds are in a paraelectric state in the 5−300 K temperature range.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000282783400051 Publication Date 2010-09-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 23 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 4.857; 2010 IF: 4.326
Call Number UA @ lucian @ c:irua:84963 Serial 3041
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Author Shenderova, O.; Koscheev, A.; Zaripov, N.; Petrov, I.; Skryabin, Y.; Detkov, P.; Turner, S.; Van Tendeloo, G.
Title Surface chemistry and properties of ozone-purified detonation nanodiamonds Type A1 Journal article
Year 2011 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 115 Issue 20 Pages 9827-9837
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Nanodiamond from ozone purification (NDO) demonstrates very distinctive properties within the class of detonation nanodiamonds, namely very high acidity and high colloidal stability in a broad pH range. To understand the origin of these unusual properties of NDO, the nature of the surface functional groups formed during detonation soot oxidation by ozone needs to be revealed. In this work, thermal desorption mass spectrometry (TDMS) and IR spectroscopy were used for the identification of surface groups and it was concluded that carboxylic anhydride groups prevail on the NDO surface. On the basis of the temperature profiles of the desorbed volatile products and their mass balance, it is hypothesized that decomposition of carboxylic anhydride groups from NDO during heating proceeds by two different mechanisms. Other distinctive features of NDO in comparison with air-treated nanodiamond are also reported.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000290652200001 Publication Date 2011-04-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 105 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 4.536; 2011 IF: 4.805
Call Number UA @ lucian @ c:irua:89556 Serial 3394
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Author Bals, S.; Casavola, M.; van Huis, M.A.; Van Aert, S.; Batenburg, K.J.; Van Tendeloo, G.; Vanmaekelbergh, D.
Title Three-dimensional atomic imaging of colloidal core-shell nanocrystals Type A1 Journal article
Year 2011 Publication Nano letters Abbreviated Journal Nano Lett
Volume 11 Issue 8 Pages 3420-3424
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Colloidal coreshell semiconductor nanocrystals form an important class of optoelectronic materials, in which the exciton wave functions can be tailored by the atomic configuration of the core, the interfacial layers, and the shell. Here, we provide a trustful 3D characterization at the atomic scale of a free-standing PbSe(core)CdSe(shell) nanocrystal by combining electron microscopy and discrete tomography. Our results yield unique insights for understanding the process of cation exchange, which is widely employed in the synthesis of coreshell nanocrystals. The study that we present is generally applicable to the broad range of colloidal heteronanocrystals that currently emerge as a new class of materials with technological importance.
Address
Corporate Author Thesis
Publisher Place of Publication Washington Editor
Language Wos 000293665600062 Publication Date 2011-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984;1530-6992; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.712 Times cited 121 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 12.712; 2011 IF: 13.198
Call Number UA @ lucian @ c:irua:91263 Serial 3643
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Author Leroux, F.; Gysemans, M.; Bals, S.; Batenburg, K.J.; Snauwaert, J.; Verbiest, T.; van Haesendonck, C.; Van Tendeloo, G.
Title Three-dimensional characterization of helical silver nanochains mediated by protein assemblies Type A1 Journal article
Year 2010 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 22 Issue 19 Pages 2193-2197
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Characterization methods for the structural investigation of biotemplates for nanodevices remain widely unexplored, despite the fact that biotemplating methods for nanodevice fabrication are becoming more widespread. In this study several techniques are used to characterize the morphology and 3D distribution of silver nanoparticles deposited on insulin fibrils.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000278601400016 Publication Date 2010-03-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648;1521-4095; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 51 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 19.791; 2010 IF: NA
Call Number UA @ lucian @ c:irua:83296 Serial 3645
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Author Werner, R.; Raisch, C.; Leca, V.; Ion, V.; Bals, S.; Van Tendeloo, G.; Chasse, T.; Kleiner, R.; Koelle, D.
Title Transport, magnetic, and structural properties of La0.7Ce0.3MnO3 thin films: evidence for hole-doping Type A1 Journal article
Year 2009 Publication Physical review : B : solid state Abbreviated Journal Phys Rev B
Volume 79 Issue 5 Pages 054416,1-054416,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Cerium-doped manganite thin films were grown epitaxially by pulsed laser deposition at 720 °C and oxygen pressure pO2=125 Pa and were subjected to different annealing steps. According to x-ray diffraction (XRD) data, the formation of CeO2 as a secondary phase could be avoided for pO28 Pa. However, transmission electron microscopy shows the presence of CeO2 nanoclusters even in those films which appear to be single phase in XRD. With O2 annealing, the metal-to-insulator transition temperature increases, while the saturation magnetization decreases and stays well below the theoretical value for electron-doped La0.7Ce0.3MnO3 with mixed Mn3+/Mn2+ valences. The same trend is observed with decreasing film thickness from 100 to 20 nm, indicating a higher oxygen content for thinner films. Hall measurements on a film which shows a metal-to-insulator transition clearly reveal holes as dominating charge carriers. Combining data from x-ray photoemission spectroscopy, for determination of the oxygen content, and x-ray absorption spectroscopy (XAS), for determination of the hole concentration and cation valences, we find that with increasing oxygen content the hole concentration increases and Mn valences are shifted from 2+ to 4+. The dominating Mn valences in the films are Mn3+ and Mn4+, and only a small amount of Mn2+ ions can be observed by XAS. Mn2+ and Ce4+ XAS signals obtained in surface-sensitive total electron yield mode are strongly reduced in the bulk-sensitive fluorescence mode, which indicates hole-doping in the bulk for those films which do show a metal-to-insulator transition.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000263815400057 Publication Date 2009-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 25 Open Access
Notes (down) Esteem 026019; Fwo Approved Most recent IF: 3.836; 2009 IF: 3.475
Call Number UA @ lucian @ c:irua:76221 Serial 3725
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Author Djoković, V.; Krsmanović, R.; Božanić, D.K.; McPherson, M.; Van Tendeloo, G.; Nair, P.S.; Georges, M.K.; Radhakrishnan, T.
Title Adsorption of sulfur onto a surface of silver nanoparticles stabilized with sago starch biopolymer Type A1 Journal article
Year 2009 Publication Colloids and surfaces: B : biointerfaces Abbreviated Journal Colloid Surface B
Volume 73 Issue 1 Pages 30-35
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Adsorption of sulfide ions onto a surface of starch capped silver nanoparticles upon addition of thioacetamide was investigated. UVvis absorption spectroscopy revealed that the adsorption of the sulfide ion on the surface of the silver nanoparticles induced damping as well as blue shift of the silver surface plasmon resonance band. Further increase in thioacetamide concentration led to shift of the resonance band toward higher wavelengths indicating the formation of the continuous Ag2S layer on the silver surface. Thus fabricated nanoparticles were investigated using electron microscopy techniques (TEM, HRTEM, and HAADF-STEM) and X-ray photoelectron spectroscopy (XPS), which confirmed their coreshell structure.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000268657500005 Publication Date 2009-05-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0927-7765; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.887 Times cited 41 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 3.887; 2009 IF: 2.600
Call Number UA @ lucian @ c:irua:77972 Serial 66
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Author Casavola, M.; van Huis, M.A.; Bals, S.; Lambert, K.; Hens, Z.; Vanmaekelbergh, D.
Title Anisotropic cation exchange in PbSe/CdSe core/shell nanocrystals of different geometry Type A1 Journal article
Year 2012 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 24 Issue 2 Pages 294-302
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We present a study of Cd2+-for-Pb2+ exchange in PbSe nanocrystals (NCs) with cube, star, and rod shapes. Prolonged temperature-activated cation exchange results in PbSe/CdSe heterostructured nanocrystals (HNCs) that preserve their specific overall shape, whereas the PbSe core is strongly faceted with dominance of {111} facets. Hence, cation exchange proceeds while the Se anion lattice is preserved, and well-defined {111}/{111} PbSe/CdSe interfaces develop. Interestingly, by quenching the reaction at different stages of the cation exchange new structures have been isolated, such as coreshell nanorods, CdSe rods that contain one or two separated PbSe dots and fully zinc blende CdSe nanorods. The crystallographically anisotropic cation exchange has been characterized by a combined HRTEM/HAADF-STEM study of heterointerface evolution over reaction time and temperature. Strikingly, Pb and Cd are only intermixed at the PbSe/CdSe interface. We propose a plausible model for the cation exchange based on a layer-by-layer replacement of Pb2+ by Cd2+ enabled by a vacancy-assisted cation migration mechanism.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000299367500008 Publication Date 2011-11-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 136 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 9.466; 2012 IF: 8.238
Call Number UA @ lucian @ c:irua:94211 Serial 124
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Author Turner, S.; Tavernier, S.M.F.; Huyberechts, G.; Bals, S.; Batenburg, K.J.; Van Tendeloo, G.
Title Assisted spray pyrolysis production and characterisation of ZnO nanoparticles with narrow size distribution Type A1 Journal article
Year 2010 Publication Journal of nanoparticle research Abbreviated Journal J Nanopart Res
Volume 12 Issue 2 Pages 615-622
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Nano-sized ZnO particles with a narrow size distribution and high crystallinity were prepared from aqueous solutions with high concentrations of Zn2+ containing salts and citric acid in a conventional spray pyrolysis setup. Structure, morphology and size of the produced material were compared to ZnO material produced by simple spray pyrolysis of zinc nitrates in the same experimental setup. Using transmission electron microscopy and electron tomography it has been shown that citric acid-assisted spray pyrolysed material is made up of micron sized secondary particles comprising a shell of lightly agglomerated, monocrystalline primary ZnO nanoparticles with sizes in the 2030 nm range, separable by a simple ultrasonic treatment step.
Address
Corporate Author Thesis
Publisher Place of Publication S.l. Editor
Language Wos 000275318700025 Publication Date 2009-04-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1388-0764;1572-896X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.02 Times cited 27 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 2.02; 2010 IF: 3.253
Call Number UA @ lucian @ c:irua:81771 Serial 156
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Author Esken, D.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Fischer, R.A.
Title Au@ZIFs: stabilization and encapsulation of cavity-size matching gold clusters inside functionalized Zeolite Imidazolate Frameworks, ZIFs Type A1 Journal article
Year 2010 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 22 Issue 23 Pages 6393-6401
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The selective formation and stabilization of very small, naked metal particles inside the cavities of metal organic frameworks (MOFs) and the simultaneous realization of an even distribution of the particles throughout the crystalline MOF host matrix over a wide range of metal loading are challenging goals. MOFs reveal high specific surface areas, tunable pore sizes, and organic linkers, which are able to interact with guests. The chemically very robust zeolite imidazolate frameworks (ZIFs) are a subclass of MOFs. We chose the microporous sodalite-like ZIF-8 (Zn(MelM)(2); IM = imidazolate) and ZIF-90 (Zn(ICA)(2); ICA = imidazolate-2-carboxyaldehyde) as host matrices to influence the dispersion of imbedded gold nanoparticles (Au NPs). The metal loading was achieved via gas phase infiltration of [Au(CO)Cl] followed by a thermal hydrogenation step to form the Au NPs. Low-dose high-resolution transmission electron microscopy ((HR)TEM) and electron tomography reveal a homogeneous distribution of Au NPs throughout the ZIF matrix. The functional groups of ZIF-90 direct the anchoring of intermediate Au species and stabilize drastically smaller and quite monodisperse Au NPs in contrast to the parent not functionalized ZIF-8. The particles can be very small, match the cavity size and approach defined molecular clusters of magic numbers, i.e., Au(55), independently from the level of loading. Post-synthetic oxidation of the aldehyde groups to yield alkyl esters by the adjacent, catalytically active metal NPs is presented as a new concept of encapsulating nanoparticles inside MOFs and allows multiple steps of metal loadings without decomposition of the MOF.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000284975100025 Publication Date 2010-11-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 194 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 9.466; 2010 IF: 6.400
Call Number UA @ lucian @ c:irua:95530 Serial 208
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Author Yang, T.; Perkisas, T.; Hadermann, J.; Croft, M.; Ignatov, A.; Greenblatt, M.
Title B-site ordered perovskite LaSrMnNbO6 : synthesis, structure and antiferromagnetism Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 183 Issue 11 Pages 2689-2694
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract LaSrMnNbO6 has been synthesized by high temperature solid state reaction under 1% H2/Ar dynamic flow. The structure is determined by Rietveld refinement of the powder X-ray diffraction data. It crystallizes in the monoclinic space group P21/n with the unit cell parameters: a=5.69187(12), b=5.74732(10), c=8.07018(15) Å and β=90.0504(29)°, which were also confirmed by electron diffraction. The Mn2+ and Nb5+ ions, whose valence states are confirmed by X-ray absorption near-edge spectroscopy, are almost completely ordered over the B-site (<1% inversion) of the perovskite structure due to the large differences of both cationic size (0.19 Å) and charge. The octahedral framework displays significant tilting distortion according to Glazers tilt system a−b−c+. Upon heating, LaSrMnNbO6 decomposes at 690 °C under O2 flow or at 775 °C in air. The magnetic susceptibility data indicate the presence of long-range antiferromagnetic ordering at TN=8 K; the experimentally observed effective paramagnetic moment, μeff=5.76 μB for high spin Mn2+ (3d5, S=5/2) is in good agreement with the calculated value (μcalcd=5.92 μB).
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000284179800028 Publication Date 2010-09-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 13 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:85805 Serial 212
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Author Zhao, Q.; Lorenz, H.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Rameshan, C.; Klötzer, B.; Konzett, J.; Penner, S.
Title Catalytic characterization of pure SnO2 and GeO2 in methanol steam reforming Type A1 Journal article
Year 2010 Publication Applied catalysis : A : general Abbreviated Journal Appl Catal A-Gen
Volume 375 Issue 2 Pages 188-195
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000275580600002 Publication Date 2010-01-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-860X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.339 Times cited 20 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 4.339; 2010 IF: 3.384
Call Number UA @ lucian @ c:irua:81741 Serial 292
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Author Adamson, P.; Hadermann, J.; Smura, C.F.; Rutt, O.J.; Hyett, G.; Free, D.G.; Clarke, S.J.
Title Competing magnetic structures and the evolution of copper ion/vacancy ordering with composition in the manganite oxide chalcogenides Sr2MnO2Cu1.5(S1-xSex)2 Type A1 Journal article
Year 2012 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 24 Issue 14 Pages 2802-2816
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The series Sr2MnO2Cu1.5(S1-xSex)(2) (0 <= x <= 1) contains mixed-valent Mn ions (Mn2+/Mn3+) in MnO2 sheets which are separated by copper-deficient antifluorite-type Cu(2-delta)Ch(2) layers with delta similar to 0.5. The compounds crystallize in the structure type first described for Sr2Mn3Sb2O2 and are described in the I4/mmm space group at ambient temperatures. Below about 250 K, ordering between Cu+ ions and tetrahedral vacancies occurs which is long-range and close to complete in the sulfide-containing end member of the series Sr2MnO2Cu1.5S2 but which occurs over shorter length scales as the selenide content increases. The superstructure is an orthorhombic 2 root 2a x root 2a x c expansion in Ibam of the room temperature cell. For x > 0.3 there are no superstructure reflections evident in the X-ray or neutron diffraction patterns, and the I4/mmm description is valid for the average structure at all temperatures. However, in the pure selenide end member, Sr2MnO2Cu1.5Se2, diffuse scattering in electron diffractograms and modulation in high resolution lattice image profiles may arise from short-range Cu/vacancy order. All members of the series exhibit long-range magnetic order. In the sulfide-rich end member and in compounds with x < 0.1 in the formula Sr2MnO2Cu1.5(S1-xSex)(2), which show well developed superstructures due to long-range Cu/vacancy order, the magnetic structure has a (1/4 1/4 0) propagation vector in which ferromagnetic zigzag chains of Mn moments in the MnO2 sheets are coupled antiferromagnetically in an arrangement described as the CE-type magnetic structure and found in many mixed-valent perovskite and Ruddlesden-Popper type oxide manganites. In these cases the magnetic cell is an a x 2b x c expansion of the low temperature Ibam structural cell. For x >= 0.2 in the formula Sr2MnO2Cu1.5(S1-xSex)(2) the magnetic structure has a (0 0 0) propagation vector and is similar to the A-type structure, also commonly adopted by some perovskite-related manganites, in which the Mn moments in the MnO2 sheets are coupled ferromagnetically and long-range antiferromagnetic order results from antiferromagnetic coupling between planes. In the region of the transition between the two different structural and magnetic long-range ordering schemes (0.1 < x < 0.2) the two magnetic structures coexist in the same sample. The evolution of the competition between magnetic ordering schemes and the length scale of the structural order with composition in Sr2MnO2Cu1.5(S1-xSex)(2) suggest that the changes in magnetic and structural order are related consequences of the introduction of chemical disorder.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000306674200024 Publication Date 2012-06-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 11 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 9.466; 2012 IF: 8.238
Call Number UA @ lucian @ c:irua:100839 Serial 435
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Author Klimczuk, T.; Wang, C.H.; Lawrence, J.M.; Xu, Q.; Durakiewicz, T.; Ronning, F.; Llobet, A.; Trouw, F.; Kurita, N.; Tokiwa, Y.; Lee, H.o.; Booth, C.H.; Gardner, J.S.; Bauer, E.D.; Joyce, J.J.; Zandbergen, H.W.; Movshovich, R.; Cava, R.J.; Thompson, J.D.;
Title Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru Type A1 Journal article
Year 2011 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 84 Issue 7 Pages 075152-075152,8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that crystallizes in the cubic CsCl structure. Valence-band photoemission (PES) and L3 x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a Γ7-doublet ground state and a Γ8 quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ6-excited state resides at 32 meV; however, the Γ8/Γ6 transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K there is a peak in specific heat that is too broad to represent a magnetic-phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand this peak also is too narrow to represent the Kondo effect in the Γ7-doublet ground state. On the basis of the field dependence of the specific heat, we argue that antiferromagnetic (AF) short-range order (SRO) (possibly coexisting with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000293830800003 Publication Date 2011-08-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 8 Open Access
Notes (down) Esteem 026019 Approved Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:92427 Serial 555
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