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Author Huve, M.; Martin, C.; Maignan, A.; Michel, C.; Van Tendeloo, G.; Hervieu, M.; Raveau, B.
Title A new cuprate with mercury bilayers : the “2222” oxide Hg2-xMxBa2Pr2Cu2O10-\delta (M= Cu,Pr) Type A1 Journal article
Year 1995 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 114 Issue 1 Pages 230-235
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A ''2222'' cuprate with mercury bilayers (Hg1.5Cu0.2Pr0.3)Ba2Pr2Cu2O10-delta, has been synthesized for the first time. It crystallizes in the P4/nmm space group with a = 3.9072(1) Angstrom and c = 17.219(1) Angstrom. The powder XRD and HREM studies of this new cuprate show that its structure consists of an intergrowth of double pyramidal (oxygen-deficient perovskite) copper layers, with double fluorite-type layers and distorted triple rock salt layers (mercury bilayers). The structure of this phase can be deduced from that of the ''2212'' mercury cuprate (Hg1.5Cu0.2Pr0.3)Ba2PrCu2O8-delta by the introduction of one additional [PrO2]infinity fluorite layer. The regular stacking of the metallic layer and the uniform cationic distribution in the mercury bilayers are remarkable features of this cuprate. The stabilization of the mercury bilayers by praseodymium and the absence of superconductivity are discussed. (C) 1995 Academic Press, Inc.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos A1995QA17000033 Publication Date 2002-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.133 Times cited 6 Open Access
Notes Approved PHYSICS, APPLIED 28/145 Q1 #
Call Number UA @ lucian @ c:irua:104448 Serial 2310
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Author Radaelli, P.G.; Marezio, M.; Tholence, J.L.; Debrion, S.; Santoro, A.; Huang, Q.; Capponi, J.J.; Chaillout, C.; Krekels, T.; Van Tendeloo, G.
Title Crystal-structure of the double-hg-layer copper-oxide superconductor (Hg,Pr)2Ba2(Y,Ca)Cu2O8-\deltaas a function of doping Type A1 Journal article
Year 1995 Publication The journal of physics and chemistry of solids Abbreviated Journal J Phys Chem Solids
Volume 56 Issue 10 Pages 1471-1478
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The crystal structure of the newly discovered double-Hg-layer copper oxide superconductor (Hg, Pr)(2)Ba-2(Y, Ca)Cu2O8-delta was studied as a function of chemical doping using neutron and electron diffraction and high-resolution transmission electron microscopy (HREM). Rietveld refinements of the structural parameters from neutron powder diffraction data indicate that the oxygen site O3 on the mercury plane is highly defective, being both partially occupied and displaced from the high-symmetry position. The variable concentration of oxygen vacancies partially compensates for the cation doping and, together with the O3 displacement field, makes some of the Hg atoms acquire an unusual pyramidal coordination. HREM images confirm that the structure is of the '2212' type, with very few defects. In some grains, faint superstructure reflections were evidenced by electron diffraction, suggesting that both the oxygen vacancies and the O3 displacement field may order at least on a local scale.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos A1995RR95600025 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3697; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.853 Times cited 16 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:104423 Serial 574
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Author Muret, P.; Nguyen, T.T.A.; Frangis, N.; Van Tendeloo, G.; van Landuyt, J.
Title Photoelectric and electrical responses of several erbium silicide/silicon interfaces Type A1 Journal article
Year 1996 Publication Applied surface science T2 – International Symposium on Si Heterostructures – From Physics to Devices, SEP 11-14, 1995, IRAKLION, GREECE Abbreviated Journal Appl Surf Sci
Volume 102 Issue Pages 173-177
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In this work, photoelectric yield and electrical properties of several types of epitaxial erbium silicide on silicon Schottky diodes are studied, Different preparation conditions are used simultaneously on n- and p-Si(111) substrates for the 200 Angstrom thick silicide films. A last type of sample consists in 1.3 monolayer of epitaxial silicide with root 3 X root 3 superstructure on the Si substrate and covered by silver on the top. Photocurrent measurements are done as a function of photon energy at several temperatures. All these samples show barrier heights near 1 eV on p-type Si, even for the interface comprising only 1.3 monolayer of silicide whereas barrier heights on n-rype Si span the range from 0.28 to 0.67 eV for this last kind of sample, the sum of the barriers always exceeding the silicon band gap, These photoelectric results are confirmed by electrical characterisations, All these results show that the Fermi level is pinned 0.1 eV below the conduction band edge on p-type Si but shifts to various positions lower within the band gap on n-type Si. This fact leads to the hypothesis of a density of -7 interface states close to the charge change in the Si depletion zone from p- to n-type, namely 10(12) eV(-1) cm(-2). Although some inhomogeneities and defects at the interface are detected by electron microscopy for samples annealed at 750 degrees C, Fermi level position seems rather insensitive to the structural details of the interface while the silicide thickness plays a role on n-type Si.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1996VJ86100039 Publication Date 2003-05-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.711 Times cited 3 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:104392 Serial 2611
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Author Luhrs, C.C.; Molins, E.; Van Tendeloo, G.; Beltran-Porter, D.; Fuertes, A.
Title Crystal structure of Bi6Sr8-xCa3+xO22(-0.5\leq x\leq1.7): a mixed valence bismuth oxide related to perovskite Type A1 Journal article
Year 1998 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 10 Issue 7 Pages 1875-1881
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The crystal structure of BiSr8-xCa3+xO22 has been determined by single-crystal X-ray diffraction. This phase is the same as Bi9Sr11Ca5Oy that was previously studied by several authors as a secondary phase in the Bi-Sr-Ca-Cu-O system and coexists in thermodynamic equilibrium with the superconductors Bi2Sr2CuO6 and Bi2Sr2CaCu2O8 It crystallizes in the monoclinic space group P2(1)/c, with cell parameters a 11.037(3) Angstrom, b = 5.971(2) Angstrom, c = 19.703(7) Angstrom, beta = 101.46(3)degrees Z = 2. The structure was solved by direct methods and full-matrix least-squares refinement. It is built up by perovskite-related blocks of composition [Sr8-xBi2Ca3+xO16] that intergrow with double rows [Bi4O6] running along b. The perovskite blocks are formed by groups of five octahedra that are shifted from each other 3/2 root 2a(p) along [110](p) (a(p) being the parameter of the cubic perovskite subcell) in a zigzag configuration and are aligned with this direction parallel to the one forming an angle of 25" with the c axis. In turn, the perovskite blocks [Sr8-xBi2Ca3+xO16] are shifted from each other 1/2 of both a(p) and root 2a(p) along [100](p) and [110](p), respectively. In the double rows, two trivalent bismuth atoms are placed, forming dimeric anion complexes [Bi2O6].(6-).6- The oxygen atoms around bismuth in these dimers are placed in the vertexes of a distorted trigonal bipyramid, with one vacant position that would be occupied by the lone pairs characteristic for the electronic configuration of Bi(III). The B sites in the perovskite blocks are occupied by pentavalent bismuth atoms and calcium atoms; the remaining Sr and Ca ions occupy the A sites of the perovskite blocks with coordination numbers with oxygen ranging from 10 to 12. The mean valence for Bi is +3.67 [33.3% of Bi(V) and 66.7% of Bi(III)]. The oxygen vacancies are located in the boundaries between domains having the two possible configurations of the perovskite subcell as in the anionic superconductor Bi3BaO5.5. The oxidation of Bi6Sr8-xCa3+xO22 at 650 degrees C allows the complete filling of the oxygen vacancies to form the double perovskite (Sr2-xCax)Bi1.4Ca0.6O6 that shows 92.5% of bismuth in +5 oxidation state. The experimental high-resolution electon microscopy image and the electron diffraction pattern of powder samples along the [010]* zone axis are in good agreement with those calculated from the structural model obtained by single-crystal X-ray diffraction. The material is almost free of defects and the occurrence of planar defects is very exceptional.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000075019300023 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 6 Open Access
Notes Approved Most recent IF: 9.466; 1998 IF: 3.359
Call Number UA @ lucian @ c:irua:104328 Serial 570
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Author Monot, I.; Tancret, F.; Laffez, P.; Van Tendeloo, G.; Desgardin, G.
Title Microstructure and properties of oxygen controlled melt textured NdBaCuO superconductive ceramics Type A1 Journal article
Year 1999 Publication Technology Abbreviated Journal Mater Sci Eng B-Adv
Volume 65 Issue 1 Pages 26-34
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Nd1+xBa2-xCu3O7-delta (123) bulk superconductors have been synthesised by the oxygen controlled melt growth method. Unlike the YBaCuO system, platinum doping or Nd4Ba2Cu2O10 (422) rich compositions do not refine the peritectic '422' secondary phase, but the latter improves the microstructural quality. Low oxygen partial pressure and high purity precursors are necessary to achieve in a reproducible manner high T-c and J(c) (up to 56 000 A/cm(2) in 0T and 30 000 A/cm(2) under 1.5T). The fishtail effect observed at 77 K is compared with the one observed in the YBCO system, and is discussed in terms of oxygen deficiency, Nd-Ba substitution, defects and vortex lattice. Our TEM observations did not evidence any Nd-Ba substituted clusters in the Nd123 matrix; however, some diffuse streaks, observed in the [100] zone ED pattern, support the fact that the source of the peak effect in this system is mainly due to oxygen disorder and low stability of the orthorhombic phase. (C) 1999 Elsevier Science S.A. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000083432000005 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-5107; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.552 Times cited 5 Open Access
Notes Approved Most recent IF: 2.552; 1999 IF: 0.690
Call Number UA @ lucian @ c:irua:104286 Serial 2060
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Author Maignan, A.; Martin, C.; Van Tendeloo, G.; Hervieu, M.; Raveau, B.
Title Size mismatch : a crucial factor for generating a spin-glass insulator in manganites Type A1 Journal article
Year 1999 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 60 Issue 22 Pages 15214-15219
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Thr structural, electronic, and magnetic properties of the highly mismatched perovskite oxides, Th(0.35)A(0.65)MnO(3), where Ais for the alkaline earth divalent cations (Ca, Ba, Sr), which are all characterized by the same large tolerance factor (t=0.934), have been investigated by using electron microscopy, electrical resistivity, magnetic susceptibility, and magnetization. It is clearly established that a transition from ferromagnetic metallic towards spin-glass insulator samples is induced as the A-site cationic size mismatch is increased. Moreover, the magnetoresistance (MR) properties of these manganites are strongly reduced for the spin-glass insulators, demonstrating that the A-sire cationic disorder is detrimental for the colossal MR properties. Based on these results, a new electronic and magnetic diagram is established that shows that the A-site disorder, rather than the A-site average cationic size (or t) is the relevant factor for generating spin-glass insulating manganites. [S0163-1829(99)01746-4].
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000084631600039 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 75 Open Access
Notes Approved Most recent IF: 3.836; 1999 IF: NA
Call Number UA @ lucian @ c:irua:104280 Serial 3038
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Author Schuddinck, W.; Van Tendeloo, G.; Barnabé, A.; Hervieu, M.; Raveau, B.
Title Relation between structure, charge ordering and magnetotransport properties in Nd0.5Ca0.5Mn1-xCrxO3 manganites Type A1 Journal article
Year 2000 Publication Journal of magnetism and magnetic materials T2 – Symposium G Material Physics Issues and Applications of Magnetic Oxides, at the E-MRS Spring Meeting, JUN 01-04, 1999, Strasbourg, France Abbreviated Journal J Magn Magn Mater
Volume 211 Issue 1-3 Pages 105-110
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The relationships between incommensurability, charge ordering and magnetotransport properties in Nd0.5Ca0.5Mn1-xCrxO3 manganites have been studied by electron diffraction and lattice imaging versus temperature with 0.02 less than or equal to x less than or equal to 0.07. All compositions show an incommensurate superstructure over the whole temperature domain, despite the fact that they are ferromagnetic and conductive below 140 K, The q-vector (1/2 – delta)a* decreases with increasing temperature for all compositions x. For a given temperature q also decreases with x. Lattice images obtained at low temperature give a clear view of the characteristics of the incommensurate structure. They also provide a better understanding of the charge ordering process. The low-temperature form of the Cr-doped manganites is not a perfectly doubled cell [[2a(p)root 2 x 2a(p) x a(p)root 2]], but defects inducing a tripled cell occur pseudo-periodically. (C) 2000 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000085772100017 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-8853; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.63 Times cited 16 Open Access
Notes Approved Most recent IF: 2.63; 2000 IF: 0.996
Call Number UA @ lucian @ c:irua:104256 Serial 2858
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Author Lei, C.H.; Van Tendeloo, G.; Siegert, M.; Schubert, J.; Buchal, C.
Title Structural investigation of the epitaxial yittria-stabilized zirconia films deposited on (001) silicon by laser ablation Type A1 Journal article
Year 2001 Publication Journal of crystal growth Abbreviated Journal J Cryst Growth
Volume 222 Issue 3 Pages 558-564
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Yittria-stabilized zirconia (YSZ) films doped with 3 and 9 vol%. Y(2)O(3), respectively, are epitaxially deposited on (0 0 1) silicon substrates by means of pulsed laser deposition (PLD) technique. Transmission electron microscopy (TEM) and X-ray diffraction are mainly combined to study the film microstructure. It is: found that the film structure strongly depends on the amount of Y(2)O(3) dopant. 99/0 Y(2)O(3)-doped films display a near cubic structure; 45 degrees 1/2(1 1 0) dislocations are the main defects in the film and thermal cracks are formed during cooling. The 3% Y(2)O(3)-doped films are dominated by {1 1 0} twin-related tetragonal domains in which monoclinic phase is found. The films are free of thermal cracks even for films thicker than 2 mum. (C) 2001 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000166701500020 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-0248; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.751 Times cited 12 Open Access
Notes Approved Most recent IF: 1.751; 2001 IF: 1.283
Call Number UA @ lucian @ c:irua:104211 Serial 3240
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Author Giorgio, S.; Henry, C.R.; Pauwels, B.; Van Tendeloo, G.
Title Au particles supported on (110) anatase-TiO2 Type A1 Journal article
Year 2001 Publication Microstructure And Processing Abbreviated Journal Mat Sci Eng A-Struct
Volume 297 Issue 1-2 Pages 197-202
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Au particles were prepared by evaporation in ultra high vacuum at high temperature, on the surfaces of TiO2 micro-spheres with the anatase structure. The morphology and the structural deformation in Au deposits were studied by high resolution transmission electron microscopy and image simulations by the multislice technique. The particles were polyhedral, limited by (100) and (111) faces. Patches with a hexagonal lattice were found around the particles, which was interpreted as thin Au islands on the surface. In these islands the Au lattice was deformed and perfectly accommodated to the (110) surface of TiO2. (C) 2001 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000166241400026 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-5093; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 3.094 Times cited 40 Open Access
Notes Approved Most recent IF: 3.094; 2001 IF: 0.978
Call Number UA @ lucian @ c:irua:104204 Serial 206
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Author Colomer, J.-F.; Henrard, L.; Lambin, P.; Van Tendeloo, G.
Title Electron diffraction of nanotubes bundles : unique helicity and tube-tube atomically coherent packing Type P1 Proceeding
Year 2002 Publication AIP conference proceedings T2 – 16th International Winterschool on Electronic Properties of Novel, Materials, MAR 02-09, 2002, KIRCHBERG, AUSTRIA Abbreviated Journal
Volume Issue Pages 314-317
Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)
Abstract The atomic structure of single-wall carbon nanotube bundles produced by three different techniques has been characterized by electron diffraction and microscopy. Small bundles produced by Catalytical Chemical Vapor Deposition (CCVD) exhibit only one or two tube chiralities within a single bundle while bundles produced by arc-discharge or laser-ablation exhibit more chiralities. A detailed analysis of the central line of diffraction is also presented. The CCVD nanotubes present more intense spots around 1.7 Angstrom(-1) < k < 2Angstrom(-1) (k is the momentum transfer) compared to what is observed for nanotubes produced by other methods. Amongst the possible explanation for such an anomaly, we put forward that in this range of momentum transfer, the relative tube orientations and translations are important for what concerns the interpretation of the diffraction peaks intensities.
Address
Corporate Author Thesis
Publisher Place of Publication New York Editor
Language Wos 000178866600070 Publication Date 2003-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume 633 Series Issue Edition
ISSN 0-7354-0088-1; 0094-243x ISBN Additional Links (down) UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:104172 Serial 921
Permanent link to this record
 

 
Author Krsmanovic, R.; Morozov, V.A.; Lebedev, O.I.; Polizzi, S.; Speghini, A.; Bettinelli, M.; Van Tendeloo, G.
Title Structural and luminescence investigation on gadolinium gallium garnet nanocrystalline powders prepared by solution combustion synthesis Type A1 Journal article
Year 2007 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 18 Issue 32 Pages 325604-325609
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Nanocrystalline powders of undoped and lanthanide (Pr3+, Tm3+)- doped gadolinium gallium garnet, Gd3Ga5O12 (GGG), were prepared by propellant synthesis and studied by x-ray powder diffraction (XRD), electron diffraction (ED), high-resolution electron microscopy (HREM) and luminescence spectroscopy. The x-ray diffraction patterns of the GGG samples were analysed using the Rietveld method. The Rietveld refinement reveals the existence of two garnet-type phases: both are cubic (space group Ia $(3) over bar $d) with a slightly different lattice parameter and probably a slightly different composition. Electron diffraction and electron microscopy measurements confirm the x-ray diffraction results. EDX measurements for lanthanide-doped samples show that stable solid solutions with composition Gd(3-x)Ln(x)Ga(5)O(12), x approximate to 0.3 ( Ln = Pr; Tm) have been obtained. The luminescence properties of the Tm3+ -doped nanocrystalline GGG samples were measured and analysed.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000248231300010 Publication Date 2007-07-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484;1361-6528; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited 33 Open Access
Notes Iap5-01 Approved Most recent IF: 3.44; 2007 IF: 3.310
Call Number UA @ lucian @ c:irua:104042 Serial 3195
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Author Sudheendra, L.; Moshnyaga, V.; Lebedev, O.I.; Gehrke, K.; Belenciuc, A.; Shapoval, O.; Van Tendeloo, G.; Samwer, K.
Title A-site ordering and stripe phases in manganite films Type A1 Journal article
Year 2008 Publication Physica: B : condensed matter T2 – International Conference on Strongly Correlated Electron Systems (SCES, 2007), MAY 13-18, 2007, Houston, TX Abbreviated Journal Physica B
Volume 403 Issue 5-9 Pages 1645-1646
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Insulating and metallic stripes above and below the Curie temperature, T-C, respectively, were observed by a high-resolution scanning tunneling microscopy (STM) and/or spectroscopy (STS) in A-site ordered and macroscopically strain free epitaxial La0.75Ca0.25MnO3 film grown on MgO substrate. The “insulating” stripes were found to be incommensurable to the lattice and aligned along (110) direction. Metallic stripes were commensurable with periodicity 2a(p)similar to 0.8 nm and aligned parallel to the crystallographic a/b-axis. Formation of these stripes involves competing charge, orbital, and lattice orders and is an outcome of an overlapping of electron wave functions mediated by the local lattice-strain distribution, existed even in A-site ordered film due to the difference in cation radii of La and Ca. (C) 2007 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000254689900330 Publication Date 2007-11-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links (down) UA library record; WoS full record
Impact Factor 1.386 Times cited Open Access
Notes Approved Most recent IF: 1.386; 2008 IF: 0.822
Call Number UA @ lucian @ c:irua:104031 Serial 26
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Author Buschmann, V.; Rodewald, M.; Fuess, H.; Van Tendeloo, G.; Schäffer, C.
Title High resolution electron microscopy study of molecular beam epitaxy grown CoSi2/Si1-xGex/Si(100) heterostructurs Type A1 Journal article
Year 1999 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 85 Issue 4 Pages 2119-2123
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Two CoSi2/Si1-xGex/Si(100) heterostructures, with different Ge content, made by molecular beam epitaxy are characterized by high resolution electron microscopy. In general, the interface between the CoSi2 thin film and the Si1-xGex layer is of a high structural quality and the strained Si1-xGex layer exhibits few defects. For both samples, different interface structures are present, although the dominant interfacial configuration is similar to the unreconstructed interface present at the CoSi2/Si(100) interface. Only occasionally (2x1) reconstructed interface regions are found which are just a few nanometers in length. Phenomena such as Ge segregation and the introduction of defects are also observed in the Si1-xGex layer. We attribute the minimal presence of the reconstructed interface to both the (2x8):Si1-xGex(100) surface reconstruction and the Ge segregation that takes place. (C) 1999 American Institute of Physics. [S0021-8979(99)02104-0].
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000078403000017 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 6 Open Access
Notes Approved Most recent IF: 2.068; 1999 IF: 2.275
Call Number UA @ lucian @ c:irua:103977 Serial 1455
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Author Colomer, J.F.; Stephan, C.; Lefrant, S.; Van Tendeloo, G.; Willems, I.; Konya, Z.; Fonseca, A.; Laurent, C.; Nagy, J.B.
Title Large-scale synthesis of single-wall carbon nanotubes by catalytic chemical vapor deposition (CCVD) method Type A1 Journal article
Year 2000 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett
Volume 317 Issue 1-2 Pages 83-89
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The large-scale production of single-wall carbon nanotubes (SWNTs) is reported. Large quantities of SWNTs can be synthesised by catalytic decomposition of methane over well-dispersed metal particles supported on MgO at 1000 degrees C. The thus produced SWNTs can be separated easily from the support by a simple acidic treatment to obtain a product with high yields (70-80%) of SWNTs. Because the typical synthesis time is 10 min, 1 g of SWNTs can be synthesised per day by this method. The SWNTs are characterized by high-resolution transmission electron microscopy and by Raman spectroscopy, showing the quality and the quantity of products. (C) 2000 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000085128300015 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2614; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.815 Times cited 344 Open Access
Notes Approved Most recent IF: 1.815; 2000 IF: 2.364
Call Number UA @ lucian @ c:irua:103957 Serial 1782
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Author Willems, I.; Konya, Z.; Colomer, J.F.; Van Tendeloo, G.; Nagaraju, N.; Fonseca, A.; Nagy, J.B.
Title Control of the outer diameter of thin carbon nanotubes synthesized by catalytic decomposition of hydrocarbons Type A1 Journal article
Year 2000 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett
Volume 317 Issue 1-2 Pages 71-76
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Multi-wall carbon nanotubes have been produced by the catalytic decomposition of acetylene. Go-Mo, Co-V and Co-Fe mixtures supported either on zeolite or corundum alumina were used as catalysts. When Fe or V is added to Co, the carbon deposit increases. The nanotubes were characterized by both low and high resolution TEM. From histograms representing the outer diameter distributions, it is clear that the outer diameter of the nanotubes can be controlled by choosing the appropriate catalyst. (C) 2000 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000085128300013 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2614; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.815 Times cited 130 Open Access
Notes Approved Most recent IF: 1.815; 2000 IF: 2.364
Call Number UA @ lucian @ c:irua:103956 Serial 499
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Author Blumenau, A.T.; Jones, R.; Frauenheim, T.; Willems, B.; Lebedev, O.I.; Van Tendeloo, G.; Fisher, D.; Martineau, P.M.
Title Dislocations in diamond : dissociation into partials and their glide motion Type A1 Journal article
Year 2003 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 68 Issue 1 Pages 014115-14119
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The dissociation of 60degrees and screw dislocations in diamond is modeled in an approach combining isotropic elasticity theory with ab initio-based tight-binding total-energy calculations. Both dislocations are found to dissociate with a substantial lowering of their line energies. For the 60degrees dislocation, however, an energy barrier to dissociation is found. We investigate the core structure of a screw dislocation distinguishing “shuffle,” “mixed,” and “glide” cores. The latter is found to be the most stable undissociated screw dislocation. Further, the glide motion of 90degrees and 30degrees partials is discussed in terms of a process involving the thermal formation and subsequent migration of kinks along the dislocation line. The calculated activation barriers to dislocation motion show that the 30degrees partial is less mobile than the 90degrees partial. Finally, high-resolution electron microscopy is performed on high-temperature, high-pressure annealed natural brown diamond, allowing the core regions of 60degrees dislocations to be imaged. The majority of dislocations are found to be dissociated. However, in some cases, undissociated 60degrees dislocations were also observed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000184582900050 Publication Date 2003-08-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 39 Open Access
Notes Approved Most recent IF: 3.836; 2003 IF: NA
Call Number UA @ lucian @ c:irua:103800 Serial 734
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Author Lukashin, A.V.; Eliseev, A.A.; Zhuravleva, N.G.; Vertegel, A.A.; Tretyakov, Y.D.; Lebedev, O.I.; Van Tendeloo, G.
Title One-step synthesis of shelled PbS nanoparticles in a layered double hydroxide matrix Type A1 Journal article
Year 2004 Publication Mendeleev communications Abbreviated Journal Mendeleev Commun
Volume Issue 4 Pages 174-176
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The one-step preparation of capped PbS nanoparticles in an inorganic matrix via UV-induced decomposition of lead thiosulfate complexes intercalated into a hydrotalcite-type layered double hydroxide is reported.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000224247100025 Publication Date 2004-09-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9436; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.741 Times cited 9 Open Access
Notes Approved Most recent IF: 1.741; 2004 IF: 0.640
Call Number UA @ lucian @ c:irua:103735 Serial 2468
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Author Li, Y.; Zhang, X.; Shen, L.; Luo, J.; Tao, X.; Liu, F.; Xu, G.; Wang, Y.; Geise, H.J.; Van Tendeloo, G.
Title Controlling the diameters in large-scale synthesis of single-walled carbon nanotubes by catalytic decomposition of CH4 Type A1 Journal article
Year 2004 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett
Volume 398 Issue 1-3 Pages 276-282
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract High-quality single-walled carbon nanotubes (SWNTs) are synthesized in gram amount on Fe-Mo/MgO catalysts by catalytic decomposition of CH4 in H-2 or N-2. Raman data reveal that the as-prepared SATNTs have a diameter of about 0.74-1.29 nm. It is found that the diameter of the as-prepared SWNTs can be controlled mainly by adjusting the molar ratio of Fe-Mo versus the MgO support. Several other factors that potentially influence the growth of SWNTs have been studied in detail. The experimental results show that the nature of the catalyst determines the diameter of the as-prepared SWNTs. (C) 2004 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000224720300050 Publication Date 2004-10-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2614; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.815 Times cited 45 Open Access
Notes Approved Most recent IF: 1.815; 2004 IF: 2.438
Call Number UA @ lucian @ c:irua:103720 Serial 507
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Author Villani, K.; Vermandel, W.; Smets, K.; Liang, D.; Van Tendeloo, G.; Martens, J.A.
Title Platinum particle size and support effects in NOx mediated carbon oxidation over platinum catalysts Type A1 Journal article
Year 2006 Publication Environmental science & technology Abbreviated Journal Environ Sci Technol
Volume 40 Issue 8 Pages 2727-2733
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Platinum metal was dispersed on microporous, mesoporous, and nonporous support materials including the zeolites Na-Y, Ba-Y, Ferrierite, ZSM-22, ETS-10, and AlPO-11, alumina, and titania. The oxidation of carbon black loosely mixed with catalyst powder was monitored gravimetrically in a gas stream containing nitric oxide, oxygen, and water. The carbon oxidation activity of the catalysts was found to be uniquely related to the Pt dispersion and little influenced by support type. The optimum dispersion is around 3-4% corresponding to relatively large Pt particle sizes of 2040 nm. The carbon oxidation activity reflects the NO oxidation activity of the platinum catalyst, which reaches an optimum in the 20-40 nm Pt particle size range. The lowest carbon oxidation temperatures were achieved with platinum loaded ZSM-22 and AlPO-11 zeolite crystallites bearing platinum of optimum dispersion on their external surfaces.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000236992700038 Publication Date 2006-04-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-936X;1520-5851; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 6.198 Times cited 29 Open Access
Notes Comet; Goa Approved Most recent IF: 6.198; 2006 IF: 4.040
Call Number UA @ lucian @ c:irua:103628 Serial 2651
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Author Dobrynin, A.N.; Temst, K.; Lievens, P.; Margueritat, J.; Gonzalo, J.; Afonso, C.N.; Piscopiello, E.; Van Tendeloo, G.
Title Observation of Co/CoO nanoparticles below the critical size for exchange bias Type A1 Journal article
Year 2007 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 101 Issue 11 Pages 113913-113917
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We compare the magnetic properties of pure and oxidized Co nanoparticles embedded in an amorphous Al2O3 matrix. Nanoparticles with diameters of 2 or 3 nm were prepared by alternate pulsed laser deposition in high vacuum conditions, and some of them were exposed to O-2 after production and before being embedded. The nanoparticles are organized in layers, the effective edge-to-edge in-depth separation being 5 or 10 nm. The lower saturation magnetizations per Co atom for the samples containing oxidized nanoparticles provide evidence for the formation of antiferromagnetic CoO shells in the nanoparticles. None of the samples with Co/CoO nanoparticles show exchange bias, while vertical hysteresis loop shifts and enhanced coercivities (as compared to samples with pure Co nanoparticles) are observed. This constitutes evidence for the nanoparticles size being in all cases smaller than the critical size for exchange bias. The difference in coercivity versus temperature dependences for the samples with pure and oxidized Co nanoparticles shows that the exchange anisotropy in Co/CoO nanoparticles appears at temperatures lower than 50 K. (c) 2007 American Institute of Physics.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000247306000098 Publication Date 2007-06-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 27 Open Access
Notes Approved Most recent IF: 2.068; 2007 IF: 2.171
Call Number UA @ lucian @ c:irua:103596 Serial 2415
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Author Ahonen, P.P.; Kauppinen, E.I.; Joubert, J.C.; Deschanvres, J.L.; Van Tendeloo, G.
Title Preparation of nanocrystalline titania powder via aerosol pyrolysis of titanium tetrabutoxide Type A1 Journal article
Year 1999 Publication Journal of materials research Abbreviated Journal J Mater Res
Volume 14 Issue 10 Pages 3938-3948
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Nanocrystalline titanium dioxide was prepared via aerosol pyrolysis of titanium alkoxide precursor at 200-580 degrees C in air and in nitrogen atmospheres. Powders were characterized by x-ray diffraction, thermogravimetric analysis, Brunauer-Emmett-Teller analysis, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, x-ray fluorescence, Raman and infrared spectroscopy, and Berner-type low-pressure impactor. The anatase phase transition was initiated at 500 degrees C in nitrogen and at 580 degrees C in air. Under other conditions amorphous powders were observed and transformed to nanocrystalline TiO2 via thermal postannealing. In air, smooth and spherical particles with 2-4-mu m diameter were formed with an as-expected tendency to convert to rutile in the thermal postannealings. In nitrogen, a fraction of the titanium tetrabutoxide precursor evaporated and formed ultrafine particles via the gas-to-particle conversion. At 500 degrees C thermally stable anatase phase was formed in nitrogen. A specific surface area as high as 280 m(2) g(-1) was observed for an as-prepared powder.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000083163700019 Publication Date 2008-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0884-2914;2044-5326; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.673 Times cited 38 Open Access
Notes Approved Most recent IF: 1.673; 1999 IF: 1.574
Call Number UA @ lucian @ c:irua:103485 Serial 2705
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Author Fedina, L.; Lebedev, O.I.; Van Tendeloo, G.; van Landuyt, J.; Mironov, O.A.; Parker, E.H.C.
Title In situ HREM irradiation study of point-defect clustering in MBE-grown strained Si1-xGex/(001)Si structures Type A1 Journal article
Year 2000 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 61 Issue 15 Pages 10336-10345
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000086606200082 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 27 Open Access
Notes Conference Name: Microsc. Semicond. Mater. Conf. Approved Most recent IF: 3.836; 2000 IF: NA
Call Number UA @ lucian @ c:irua:103456 Serial 1577
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Author Hervieu, M.; Martin, C.; Maignan, A.; Van Tendeloo, G.; Jirak, Z.; Hejtmanek, J.; Barnabe, A.; Thopart, D.; Raveau, B.
Title Structural and magnetotransport transitions in the electron-doped Pr1-xSrxMnO3(0.85\leq x\leq1) manganites Type A1 Journal article
Year 2000 Publication Chemistry and materials Abbreviated Journal Chem Mater
Volume 12 Issue 5 Pages 1456-1462
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The exploration of the Mn4+-rich side of the Pr1-xSrxMnO3 system has allowed the extension of the domain of the cubic perovskite, by using a two-step process, combining synthesis under Ar flow at high temperature and O-2 pressure annealing at lower temperature. We show that these Pr-doped cubic perovskites exhibit a coupled structural (cubic-tetragonal) and magnetic (para-antiferro) transition connected with a resistivity jump at the same temperature. The strong interplay between lattice, charges, and spins for these oxides results from the appearance at low temperature of the distorted C-type antiferromagnetic structure. The Pr1-xSrxMnO3 magnetic phase diagram shows, for 0.9 less than or equal to x less than or equal to 1 (i.e., on the Mn4+-rich side), the existence at low temperature of C- and G-type antiferromagnetism. The absence of ferromagnetic-antiferromagnetic competition explains that magnetoresistante properties are not observed in this system, in contrast to Mn4+-rich Ln(1-x)Ca(x)MnO(3) systems.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000087136800039 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 24 Open Access
Notes Approved Most recent IF: 9.466; 2000 IF: 3.580
Call Number UA @ lucian @ c:irua:103454 Serial 3198
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Author Van Tendeloo, G.; Garlea, O.; Darie, C.; Bougerol-Chaillout, C.; Bordet, P.
Title The fine structure of YCuO2+x delafossite determined by synchrotron powder diffraction and electron microscopy Type A1 Journal article
Year 2001 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 156 Issue 2 Pages 428-436
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract YCuO2 delafossite crystallizes into two stacking variants; hexagonal 2H or rhombohedral 3R, depending on the preparation conditions. The structure of the fully oxygenated material YCuO2.50 has been determined as orthorhombic (a(O) = 6.1961 Angstrom; b(O) = 11.2158 Angstrom; c(O) = 7.1505 Angstrom; space group Pnma). The structure is based on the hexagonal 2H structure (a(O) = a(H)root3; b(O) = c(H); c(O) = 2a(H)). Upon incomplete oxidation, a different YCuOZ phase with ideal composition YCuO2.33 and lattice parameters a(H root)3, a(H)root3, c(H) is also formed. Diffraction patterns are often very complex because of the presence of planar defects and intergrowth of both phases. Under electron beam irradiation, oxygen is released from the structure and one phase gradually transforms into the other. (C) 2001 Academic Press.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000167252000025 Publication Date 2002-09-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 33 Open Access
Notes Approved Most recent IF: 2.299; 2001 IF: 1.614
Call Number UA @ lucian @ c:irua:103425 Serial 3581
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Author Koster, G.; Verbist, K.; Rijnders, G.; Rogalla, H.; Van Tendeloo, G.; Blank, D.H.A.
Title Structure and properties of (Sr,Ca)CuO2-BaCuO2 superlattices grown by pulsed laser interval deposition Type A1 Journal article
Year 2001 Publication Physica: C : superconductivity Abbreviated Journal Physica C
Volume 353 Issue 3-4 Pages 167-183
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report on the preparation of CuBa(2)(Sr(x)Ca(1-x))(n)Cu(n-1)O(y) compounds by fabrication of (Ba,Sr,Ca)CuO(2) superlattices with pulsed laser deposition (PLD). A technique called interval deposition is used to suppress multi-level or island growth resulting in high-quality superlattice structures. Both, the applicability of PLD to atomic engineering as well as the fabrication of artificial superconductors is demonstrated. The (Sr,Ca)CuO(2)-BaCuO(2) superlattices are characterized by X-ray diffraction, high-resolution electron microscopy (HREM) and selected area electron diffraction. The superlattice period has been deduced from electron diffraction patterns and XRD measurements. For Sr containing films, the best growth behavior is observed and films with the highest degree of crystallinity are obtained, whereas superconductivity is only found in less crystalline, Ca containing films. Under some deposition conditions and depending on the amount of Ba containing layers in the superlattice, it was observed that the BaCuO(2) material is converted to Ba(2)CuO(4-delta). Image simulations to interpret the HREM contrast are performed. (C) 2001 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000168861100003 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.404 Times cited 8 Open Access
Notes Approved Most recent IF: 1.404; 2001 IF: 0.806
Call Number UA @ lucian @ c:irua:103417 Serial 3293
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Author Mishra, R.S.K.; Pandey, D.; Lemmens, H.; Van Tendeloo, G.
Title Evidence for another low-temperature phase transition in tetragonal Pb(ZrxTi1-x)O3 (x=0.515,0.520) Type A1 Journal article
Year 2001 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 64 Issue 5 Pages 054104
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Results of dielectric and resonance frequency (f(r)) measurements below room temperature are presented for Pb(ZrxTi1-x)O-3, x = 0.515 and 0.520. It is shown that the temperature coefficient of f(r) changes sign from negative to positive around 210 and 265 K for x = 0.520 and 200 and 260 K for x = 0.515. Anomalies in the real part of the dielectric constant (epsilon') are observed around the same temperatures at which the temperature coefficient of f(r) changes sign because of the electrostrictive coupling between the elastic and dielectric responses. Low-temperature powder x-ray-diffraction (XRD) data, however, reveal only one transition from the tetragonal to monoclinic phase similar to that reported by Noheda et al. [Phys. Rev. B, 61, 8687 (2000)]. Electron-diffraction data, on the other hand, reveal yet another structural transition at lower temperatures corresponding to the second anomaly in the epsilon' vs T and f(r) vs T curves. This second transition is shown to be a cell-doubling transition not observed by Noheda et al. in their XRD studies. The observation of superlattice reflections raises doubts about the correctness of the Cm space group proposed by Noheda et al. for the monoclinic phase of Pb(ZrxTi(1-x))O-3 below the second transition temperature.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000170267000028 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited Open Access
Notes Approved Most recent IF: 3.836; 2001 IF: NA
Call Number UA @ lucian @ c:irua:103407 Serial 1093
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Author Lei, C.H.; Van Tendeloo, G.; Siegert, M.; Schubert, J.
Title Microstructural investigation of BaTiO3 thin films deposited on (001) MgO Type A1 Journal article
Year 2002 Publication Journal of materials research Abbreviated Journal J Mater Res
Volume 17 Issue 8 Pages 1923-1931
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The microstructure of BaTiO3 thin films, epitaxially deposited on (001) MgO by pulsed laser ablation, has been investigated by transmission electron microscopy. The films are always c-axis-orientated, but dislocations, {111} stacking faults, and antiphase boundaries are frequently observed. Conventional TEM and high-resolution microscopy allow one to deduce the Burgers vectors of dislocations as b(1) = <100> or b(2) = <110>, both being perfect dislocations. Most extrinsic stacking faults are ending at 1/3<112> or 1/3<111> partial dislocations; the displacement vector of the antiphase boundaries is 1/2<101>. Studying the interfacial structure by means of zone images taken along [100] and [110] shows that the misfit is mainly released by dislocations with Burgers vectors of 1/2<110> and 1/2<101>.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000177208800010 Publication Date 2008-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0884-2914;2044-5326; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.673 Times cited 8 Open Access
Notes Approved Most recent IF: 1.673; 2002 IF: 1.530
Call Number UA @ lucian @ c:irua:103343 Serial 2044
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Author Antipov, E.V.; Khasanova, N.R.; Pshirkov, J.S.; Putilin, S.N.; Bougerol, C.; Lebedev, O.I.; Van Tendeloo, G.; Baranov, A.N.; Park, Y.W.
Title The superconducting bismuth-based mixed oxides Type A1 Journal article
Year 2002 Publication Current applied physics T2 – QTSM and QFS 02 Symposium, MAY 08-10, 2002, SEOUL, SOUTH KOREA Abbreviated Journal Curr Appl Phys
Volume 2 Issue 5 Pages 425-430
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The present paper describes the synthesis, characterization of mixed-valence bismuthates with three- or two-dimensional perovskite-like structures and structural criteria that influence superconductivity in these compounds. Single-phase samples of Sr1-xKxBiO3 were prepared for the broad range of K-content: 0.25 less than or equal to x less than or equal to 0.65. For these bismuthates the symmetry of the structure changes from monoclinic to orthorhombic and finally to tetragonal upon increasing the K-content thus resulting in the decrease of the Bi-O distances and reduction of the network distortions. Superconductivity with maximum T-c = 12 K exists in the narrow range (x approximate to 0.5-0.6) within the stability field of the tetragonal phase (0.33 less than or equal to x less than or equal to 0.65), when the three-dimensional octahedral framework has close to the ideal perovskite structure arrangement. The layered type (Ba,K)(3)Bi2O7 and (Ba,K)(2)BiO4 bismuthates belonging to the A(n+1)B(n)O(3n+1) homologous series were investigated. Buckling of the (BiO2) layers in the structure of the n = 2 member occurs due to the ordering of alkaline- and alkaline-earth cations between two independent positions. The formation of the one-layer bismuthate was revealed by Electron Microscopy and XRPD studies. Both types of compounds are considered to be possible candidates for new superconducting materials among bismuthates. (C) 2002 Published by Elsevier Science B.V.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000179330900015 Publication Date 2002-11-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1567-1739; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 1.971 Times cited 2 Open Access
Notes Approved Most recent IF: 1.971; 2002 IF: NA
Call Number UA @ lucian @ c:irua:103336 Serial 3598
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Author Bals, S.; Van Tendeloo, G.; Rijnders, G.; Huijben, M.; Leca, V.; Blank, D.H.A.
Title Transmission electron microscopy on interface engineered superconducting thin films Type A1 Journal article
Year 2003 Publication IEEE transactions on applied superconductivity Abbreviated Journal Ieee T Appl Supercon
Volume 13 Issue 2:3 Pages 2834-2837
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Transmission electron microscopy is used to evaluate different deposition techniques, which optimize the microstructure and physical properties of superconducting thin films. High-resolution electron microscopy proves that the use of an YBa2Cu2Ox buffer layer can avoid a variable interface configuration in YBa2Cu3O7-delta thin films grown on SrTiO3. The growth can also be controlled at an atomic level by, using sub-unit cell layer epitaxy, which results in films with high quality and few structural defects. Epitaxial strain in Sr0.85La0.15CuO2 infinite layer thin films influences the critical temperature of these films, as well as the microstructure. Compressive stress is released by a modulated or a twinned microstructure, which eliminates superconductivity. On the other hand, also tensile strain seems to lower the critical temperature of the infinite layer.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000184242400101 Publication Date 2003-07-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 13 Open Access
Notes Iuap V-1; Fwo Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:103292 Serial 3712
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Author Lazoryak, B.I.; Baryshnikova, O.V.; Stefanovich, S.Y.; Malakho, A.P.; Morozov, V.A.; Belik, A.A.; Leonidov, I.A.; Leonidova, O.N.; Van Tendeloo, G.
Title Ferroelectric and ionic-conductive properties of nonlinear-optical vanadate, Ca9Bi(VO4)7 Type A1 Journal article
Year 2003 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 15 Issue 15 Pages 3003-3010
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Structural, chemical, and physical properties of whitlockite-type Ca9Bi(VO4)(7) were studied by X-ray powder diffraction (XRD), electron diffraction (ED), second-harmonic generation (SHG), thermogravimetry, differential scanning calorimetry, dielectric, and electrical-conductivity measurements. A new phase-transition of the ferroelectric type was found in Ca9Bi(VO4)(7) with a transition temperature, T-c of 1053 +/- 3 K. The polar phase, beta-Ca9Bi(VO4)(7), is stable below T-c down to at least 160 K. The centrosymmetric beta'-phase is stable above T-c up to 1273 +/- 5 K. Above 1273 K, it decomposes to give BiVO4 and whitlockite-type solid solutions of Ca9+1.5xBi1-x(VO4)(7). The beta<---->beta' phase transition is reversible and of second order. Electrical conductivity of beta'-Ca9Bi(VO4)(7) is rather high (sigma = 0.6 x 10(-3) S/cm at 1200 K) and obeys the Arrhenius law with an activation energy of 1.0 eV. Structure parameters of Ca9Bi(VO4)(7) are refined by the Rietveld method from XRD data measured at room temperature (space group R3c; Z = 6; a = 10.8992(1) Angstrom, c = 38.1192(4) Angstrom, and V = 3921.6(1) Angstrom(3); R-wp = 3.06% and R-p = 2.36%). Bi3+ ions together with Ca2+ ions are statistically distributed among the M1, M2, M3, and M5 sites. Ca9Bi(VO4)(7) has a SHG efficiency of about 140 times that of quartz. Through the powder SHG measurements, we estimated the nonlinear optical susceptibility, Digital, at about 6.1-7.2 pm/V. This value for Ca9Bi(VO4)(7) is comparable with that for known nonlinear optical materials such as LiNbO3 and LiTaO3.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000184379900024 Publication Date 2003-07-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 51 Open Access
Notes Iup V-1; Dwtc Approved Most recent IF: 9.466; 2003 IF: 4.374
Call Number UA @ lucian @ c:irua:103284 Serial 1179
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