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“Characterisation of multilayer ramp-type REBa2Cu3O7-\delta structures by scanning probe microscopy and high-resolution electron microscopy”. Blank DHA, Rijnders AJHM, Verhoeven MAJ, Bergs RMH, Rogalla H, Verbist K, Lebedev O, Van Tendeloo G, Journal of alloys and compounds
T2 –, Symposium on High Temperature Superconductor Thin Films, Growth, Mechanisms, Interfaces, Multilayers, at the 1996 Spring Meeting of the European-Materials-Society, June 04-07, 1996, Strasbourg, France 251, 206 (1997). http://doi.org/10.1016/S0925-8388(96)02799-5
Abstract: We studied the morphology of ramps in REBa2CU3O7 (REBCO) epitaxial films on SrTiO3 substrates, fabricated by RF magnetron sputter deposition and pulsed laser deposition (PLD), by scanning probe microscopy (SPM) and high resolution electron microscopy (HREM). The ramps were fabricated by Ar ion beam etching using masks of standard photoresist and TIN. AFM-studies on ramps in sputter deposited films show a strong dependence, i.e. formation of facets and ridges, on the angle of incidence of the ion beam with respect to the substrate surface as well as the rotation angle with respect to the crystal axes of the substrate. Ramps in pulsed laser deposited films did not show this dependence, Furthermore, we studied the effect of an anneal step prior to the deposition of barrier layers (i.e. PrBa2CU3O7, SrTiO3, CeO2) on the ramp. First results show a recrystallization of the ramp surface, resulting in terraces and a non-homogeneous growth of the barrier material on top of it. The thickness variations, for thin layers of barrier material, con even become much larger than expected from the amount of deposited material and are dependent on the deposition and anneal conditions. HREM studies show a well defined interface between barrier layer and electrodes. The angle of the ramp depends on the etch rate of the mask and REBCO, and on the angle of incidence of the ion beam. TiN has a much lower etch rate compared to photoresist, resulting in an angle of the ramp comparable to the angle of incidence, resulting in a low etching rate on the ramp. These results will lead to improved electrical characteristics of ramp-type junctions.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
DOI: 10.1016/S0925-8388(96)02799-5
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“Combination of CeO2 and PtO2 doping for the strong enhancement of Jc under magnetic field in melt-textured superconductor YBaCuO”. Delamare MP, Hervieu M, Wang J, Provost J, Monot I, Verbist K, Van Tendeloo G, Physica: C : superconductivity 262, 220 (1996). http://doi.org/10.1016/0921-4534(96)00225-0
Abstract: A combination of CeO2 and PtO2 doping has been studied in melt-processed YBa2Cu3O7-x. This study was carried out using an optimized well established MTG process. The cerium-platinum doped samples exhibit a high fishtail effect with a J(c) of 4.3 x 10(4) A/cm(2) under an applied field of 1 T. Microstructural and nanostructural studies have been performed. The 211 and BaCeO3 inclusions are a few micrometers wide and the formation of a metastable nanocrystalline phase (Y4Ba4)Cu-8-x(Ce,Pt)(x)O-20+delta related to the perovskite is detected. The 123 grains show no specific extended defect generated by the doping process. The relationship between structure and properties are discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.942
Times cited: 27
DOI: 10.1016/0921-4534(96)00225-0
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“Critical assessment of the process of growth of a YBa2Cu3O7-\delta layer on Y2BaCuO5”. Jacques P, Verbist K, Lapin J, Ryelandt L, Van Tendeloo G, Delannay F, Superconductor science and technology 9, 176 (1996). http://doi.org/10.1088/0953-2048/9/3/008
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 1
DOI: 10.1088/0953-2048/9/3/008
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“Ga segregation in DyBa2Cu3O7-\delta/PrBa2Cu3-xGaxO7-\delta/DyBa2Cu3O7-\delta ramp-type Josephson junctions”. Verbist K, Lebedev OI, Van Tendeloo G, Verhoeven MAJ, Rijnders AJHM, Blank DHA, Rogalia H, Applied physics letters 70, 1167 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 8
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“Inclusions in magnetron sputtered YBa2Cu3-x MxO7-d thin films: a study by means of electron microscopy”. Verbist K, Van Tendeloo G, Ye M, Schroeder J, Mehbod M, Deltour R, Microscopy, microanalysis, microstructures 7, 17 (1996). http://doi.org/10.1051/mmm:1996104
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 6
DOI: 10.1051/mmm:1996104
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“Josephson phenomenology and microstructure of YBaCuO artificial grain boundaries characterized by misalignment of the c-axes”. Tafuri F, Granozio FM, Carillo F, Lombardi F, Di Uccio US, Verbist K, Lebedev O, Van Tendeloo G, Physica: C : superconductivity 327, 63 (1999). http://doi.org/10.1016/S0921-4534(99)00372-X
Abstract: YBa(2)Cu(3)O(7-delta) (YBCO) grain boundaries characterized by a misalignment of the c-axes (45 degrees c-axis tilt or 45 degrees c-axis twist) have been obtained by employing a recently implemented biepitaxial technique. Junctions based on these grain boundaries exhibit good Josephson properties useful for applications. High values of the I(C)R(N) product and a Fraunhofer-like dependence of the critical current on the magnetic field, differently from traditional biepitaxial junctions, have been obtained. The correlation between transport properties and microstructure has been investigated by Transmission Electron Microscopy (TEM), which was also performed on previously measured junctions. The presence of atomically clean basal plane (BP) faced tilt boundaries, among other types of interfaces, has been shown. The possibility of selecting these kinds of boundaries by controlling film growth, and their possible advantages in terms of reproducibility and uniformity of the junction properties an discussed. The possibility of employing these junctions to explore the symmetry of the order parameter is also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 7
DOI: 10.1016/S0921-4534(99)00372-X
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“The local structure of YBCO based materials by TEM”. Van Tendeloo G, Lebedev OI, Verbist K, Abakumov AM, Shpanchenko RV, Antipov EV, Blank DHA Kluwer Academic, Dordrecht, page 11 (1999).
Keywords: H1 Book chapter; Electron microscopy for materials research (EMAT)
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“Low- or high-angle Ar ion-beam etching to create ramp-type Josephson junctions”. Verbist K, Lebedev OI, Van Tendeloo G, Verhoeven MAJ, Rijnders AJHM, Blank DHA, Superconductor science and technology 9, 978 (1996). http://doi.org/10.1088/0953-2048/9/11/009
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 10
DOI: 10.1088/0953-2048/9/11/009
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“Microstructure and flux pinning properties of melt textured grown doped YBa2Cu3O7-\delta”. Monot I, Verbist K, Hervieu M, Laffez P, Delamare MP, Wang J, Desgardin G, Van Tendeloo G, Physica: C : superconductivity 274, 253 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 33
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“The microstructure and interfaces of intermediate layers in sapphire bicrystals”. Vasiliev AL, Stepantsov EA, Ivanov ZG, Verbist K, Van Tendeloo G, Olsson E, Applied surface science 119, 215 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.387
Times cited: 2
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“Microstructure and Josephson phenomenology in 45°, tilt and twist Yba2Cu3o7-\delta artificial grain boundaries”. Tafuri F, Miletto Granozio F, Carillo F, di Chiara A, Verbist K, Van Tendeloo G, Physical review : B : condensed matter and materials physics 59, 11523 (1999). http://doi.org/10.1103/PhysRevB.59.11523
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 52
DOI: 10.1103/PhysRevB.59.11523
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“Microstructure of α-axis oriented YBCO films on SrTiO3 substrates using a new template layer La4BaCu5O13”. Prouteau C, Verbist K, Hamet JF, Mercey B, Hervieu M, Raveau B, Van Tendeloo G, Physica: C : superconductivity 288, 231 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
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“Microstructure of artificial [100] 45 degrees twist grain boundaries in YBa2Cu3O7-delta”. Verbist K, Tafuri F, Granozio FM, Di Chiara S, Van Tendeloo G, Electron Microscopy 1998, Vol 2: Materials Science 1 , 593 (1998)
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT)
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“Microstructure of artificial [100] 45°, twist grain boundaries in YBa2Cu3O7-”. Verbist K, Tafuri F, Miletto Granozio F, di Chiara S, Van Tendeloo G, Electron microscopy: vol. 2 , 593 (1998)
Keywords: A3 Journal article; Electron microscopy for materials research (EMAT)
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“Microstructure of YBa2Cu3O7-\delta Josephson junctions in relation to their properties”. Verbist K, Lebedev OI, Verhoeven MAJ, Winchern R, Rijnders AJHM, Blank DHA, Tafuri F, Bender H, Van Tendeloo G, Superconductor science and technology 11, 13 (1998). http://doi.org/10.1088/0953-2048/11/1/004
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
DOI: 10.1088/0953-2048/11/1/004
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“Molecular beam epitaxy and microstructural study of La2-xSr1+xCu2O6+y thin films”. Verbist K, Milat O, Van Tendeloo G, Arrouy F, Williams EJ, Rossel C, Machler E, Locquet J-P, Physical review : B : condensed matter and materials physics 56, 853 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 2
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“Phase competition between Y2BaCuO5 and Y2O3 precipitates in Y-rich YBCO thin films”. Scotti di Uccio U, Miletto Granozio F, di Chiara A, Tafuri F, Lebedev OI, Verbist K, Van Tendeloo G, Physica: C : superconductivity 321, 162 (1999)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 17
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“A potential method to correlate electrical properties and microstructure of a unique high-Tc superconducting Josephson junction”. Verbist K, Lebedev OI, Van Tendeloo G, Tafuri F, Granozio FM, Di Chiara A, Bender H, Applied physics letters 74, 1024 (1999). http://doi.org/10.1063/1.123443
Abstract: A method to correlate microstructure from cross-section transmission electron microscopy (TEM) investigations and transport properties of a single well characterized high-T-c artificial grain boundary junction is reported. A YBa2Cu3O7-delta 45 degrees twist junction exhibiting the typical phenomenology of high T-c Josephson weak links was employed. The TEM sample preparation is based on focused ion beam etching and allows to easily localize the electron transparent area on a microbridge. The reported technique opens clear perspectives in the determination of the microstructural origin of variations in Josephson junction properties, such as the spread in I-c and IcRN values and the presence of different transport regimes in nominally identical junctions. (C) 1999 American Institute of Physics. [S0003-6951(99)03404-X].
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 5
DOI: 10.1063/1.123443
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“Structural properties of c-axis oriented epitaxial YBa2Cu3O7-\delta thin films”. Ye M, Schroeder J, Deltour R, Delplancke MP, Winand R, Verbist K, Van Tendeloo G, Superlattices and microstructures 21, 287 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.123
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“Structural properties of Zn-substituted epitaxial YBa2Cu3O7-\delta thin films”. Ye M, Schroeder J, Mehbod M, Deltour R, Naessens G, Duvigneaud PH, Verbist K, Van Tendeloo G, Superconductor science and technology 9, 543 (1996). http://doi.org/10.1088/0953-2048/9/7/006
Abstract: We optimized the deposition of YBa2(Cu1-xZnx)(3)O-7-delta thin-films using inverted cylindrical magnetron sputtering and report here a detailed structural study, especially in relation to crystal growth, associated surface morphology, Y2O3 precipitation and other secondary phases important for flux pinning. We find that the epitaxial quality of the Zn-substituted YBa2Cu3O7-delta films is decreased compared with high-quality pure YBa2Cu3O7-delta films prepared under identical conditions. The pure films have smoother surfaces, while those of Zn-substituted films contain pinholes and outgrowths. Secondary phases and a-axis grains were observed in the Zn-substituted films. Y2O3 precipitates with typical dimensions of 50-100 Angstrom have been found in both pure and Zn-substituted samples. However, their density of about 10(23) m(-3), observed in the pure films, is significantly reduced in the Zn-substituted films when increasing the Zn concentration up to 4%.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 7
DOI: 10.1088/0953-2048/9/7/006
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“Structure and properties of (Sr,Ca)CuO2-BaCuO2 superlattices grown by pulsed laser interval deposition”. Koster G, Verbist K, Rijnders G, Rogalla H, Van Tendeloo G, Blank DHA, Physica: C : superconductivity 353, 167 (2001). http://doi.org/10.1016/S0921-4534(00)01763-9
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.404
Times cited: 8
DOI: 10.1016/S0921-4534(00)01763-9
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“Structure of artificial grain boundaries in sapphire bicrystals with intermediate layers”. Vasiliev AL, Stepantsov EA, Ivanov ZG, Olsson E, Verbist K, Van Tendeloo G, Interface science 5, 223 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 3
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“Study of ramp-type Josephson junctions by HREM”. Verbist K, Lebedev OI, Van Tendeloo G, Verhoeven MAJ, Rijnders AJHM, Blank DHA, Electronic Applications, Vol 2: Large Scale And Power Applications , 49 (1997)
Abstract: Structural aspects of ramp-type Josephson junctions based on REBa2Cu3O7-delta high-T-c superconductors, are investigated by cross-section transmission electron microscopy and results related to fabrication process or physical properties. The barrier layer material is PrBa2Cu3-xGaxO7-delta. The ramp-geometry depends on the etching conditions. High levels of Ga doping (x>0.7) influence the microstructure of the barrier layer thereby changing the junctions properties.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
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“TEM study of YBa2Cu3O7-x thin films with Zn and Fe”. Verbist K, Van Tendeloo G, Ye M, Mehbod M, Deltour R, Physica: C : superconductivity 235, 663 (1994). http://doi.org/10.1016/0921-4534(94)91555-5
Abstract: Analytical and high resolution electron microscopy have been used to study the effect of Zn- and Fe-doping on the micro structure of [001] YBa2Cu3O7-x thin films on [001] MgO substrates grown by magnetron sputtering. Special attention was paid to the presence of second phase inclusions and surface outgrowths such as CuO, Y2Ba1Cu1O5-x, Y2O3 in order to establish a relationship with the critical current density.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.942
DOI: 10.1016/0921-4534(94)91555-5
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“Y2O3 inclusions in YBa2Cu3O7-\delta thin films”. Verbist K, Vasiliev AL, Van Tendeloo G, Applied physics letters 66, 1424 (1995). http://doi.org/10.1063/1.113266
Abstract: Nanoprecipitates in YBa2Cu3O7‐δ(YBCO) thin films have been identified by high resolution electron microscopy (HREM) as Y2O3 inclusions; they correspond to two different types of epitaxial relationships namely [001] or [110] parallel to the YBCOc‐axis. The [001] precipitates are situated near the YBCO surface, in the bulk and on the YBCO film/substrate interface. The [110] precipitates have only been observed at the surface. Literature data have been reinterpreted.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.302
Times cited: 28
DOI: 10.1063/1.113266
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“YBa2Cu3O7-x Josephson junctions and dc SQUIDs based on 45\text{\textdegree} a-axis tilt and twist grain boundaries : atomically clean interfaces for applications”. Tafuri F, Carillo F, Lombardi F, Granozio FM, dii Uccio US, Testa G, Sarnelli E, Verbist K, Van Tendeloo G, Superconductor science and technology
T2 –, International Superconductive Electronics Conference, JUN 21-25, 1999, BERKELEY, CALIFORNIA 12, 1007 (1999). http://doi.org/10.1088/0953-2048/12/11/393
Abstract: YBa2Cu3O7-x artificial grain boundary Josephson junctions have been fabricated, employing a recently implemented biepitaxial technique. The grain boundaries can be obtained by controlling the orientation of the MgO seed layer and are characterized by a misalignment of the c-axes (45 degrees a-axis tilt or 45 degrees a-axis twist). These types of grain boundaries are still mostly unexplored. We carried out a complete characterization of their transport properties and microstructure. Junctions and de SQUIDs associated with these grain boundaries exhibit an excellent Josephson phenomenology and high values of the ICRN product and of the magnetic flux-to-voltage transfer parameter respectively. Remarkable differences in the transport parameters of tilt and twist junctions have been observed, which can be of interest for several applications. A maximum speed of Josephson vortices as calculated from the voltage step values of the order of 2 x 10(6) m s(-1) is obtained. These devices could also have some impact on experiments designed to study the symmetry of the order parameter, exploiting their microstructure and anisotropic properties. High-resolution electron microscopy showed the presence of perfect basal plane faced boundaries in the cross sections of tilt boundaries.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 3
DOI: 10.1088/0953-2048/12/11/393
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