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“Moderate pressure synthesis of rare earth nickelate with metal-insulator transition using polymeric precursors”. Napierala C, Lepoittevin C, Edely M, Sauques L, Giovanelli F, Laffez P, Van Tendeloo G, Journal of solid state chemistry 183, 1663 (2010). http://doi.org/10.1016/j.jssc.2010.04.019
Abstract: Rare earth nickelates exhibit a reversible metalsemiconductor phase transition that is, in the infrared range, responsible for a thermo-optical contrast. The state of the art synthesis of these compounds usually requires high oxygen pressure to stabilize Ni in the oxidation state 3+. In this work, using polymeric precursor associated with moderate pressure annealing, we show that it is possible to obtain fully oxidized rare earth nickelate with metalinsulator transition. Using thermogravimetric analysis, X-ray diffraction and transmission electronic microscopy we compare different samples synthesized at different oxygen pressures and demonstrate their structural similarity. Thermo-optical properties were measured, in the infrared range, using reflectance measurements and confirmed the metalinsulator transition at 60 °C in both samples.TEM observations lead to the conclusion that the structure commonly obtained at 175 bar is perfectly observed in the 20 bar sample without major structural defects. The two samples exhibit a thermochromic behavior and thermo-optical properties of the two samples are equivalent.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 3
DOI: 10.1016/j.jssc.2010.04.019
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“Growth of La2Mo2O9 films on porous Al2O3 substrates by radio frequency magnetron sputtering”. Laffez P, Chen XY, Banerjee G, Pezeril T, Rossell MD, Van Tendeloo G, Lacorre P, Liu JM, Liu Z-G, Thin solid films : an international journal on the science and technology of thin and thick films 500, 27 (2006). http://doi.org/10.1016/j.tsf.2005.10.062
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.879
Times cited: 15
DOI: 10.1016/j.tsf.2005.10.062
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“Evidence of strain induced structural change in hetero-epitaxial NdNiO3 thin films with metal-insulator transition”. Laffez P, Lebedev OI, Ruello P, Desfeux R, Banerjee G, Capon F, European physical journal: applied physics 25, 25 (2004). http://doi.org/10.1051/epjap:2003087
Abstract: Neodymium nickelate thin films have been prepared on NdGaO3 substrates by RF magnetron sputtering and post-annealing treatment under oxygen pressure. Transport properties are found to depend strongly on film thickness. Thick films show transport properties close to bulk ceramics, while very thin films exhibit a large transition from metal to insulator which occurs over a wide temperature range with high resistivity. Structure and surface morphology of the films have been investigated by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). Thin films (approximate to17 nm) grow heteroepitaxially, while thicker films (approximate to73 nm) show a granular structure. The thinnest sample suggests a symmetry change induced by the epitaxial strain of the substrate. This paper discusses the relationship between microstructure and transport properties.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.684
Times cited: 12
DOI: 10.1051/epjap:2003087
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“Particle layering in the ceramic-metal thin film Pt-Al2O3”. Gibaud A, Hazra S, Sella C, Laffez P, Désert A, Naudon A, Van Tendeloo G, Physical review : B : condensed matter and materials physics 63, 193407 (2001). http://doi.org/10.1103/PhysRevB.63.193407
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 25
DOI: 10.1103/PhysRevB.63.193407
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“Transmission electron microscopy of NdNiO3 thin films on silicon substrates”. Laffez P, Retoux R, Boullay P, Zaghrioui M, Lacorre P, Van Tendeloo G, European physical journal: applied physics 12, 55 (2000). http://doi.org/10.1051/epjap:2000171
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.684
Times cited: 16
DOI: 10.1051/epjap:2000171
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“Microstructure and properties of oxygen controlled melt textured NdBaCuO superconductive ceramics”. Monot I, Tancret F, Laffez P, Van Tendeloo G, Desgardin G, Technology 65, 26 (1999). http://doi.org/10.1016/S0921-5107(99)00193-2
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.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.552
Times cited: 5
DOI: 10.1016/S0921-5107(99)00193-2
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“Preparation and characterization of melt textured NdBa2Cu3O7- bulk superconducting ceramics”. Tancret F, Monot I, Laffez P, Van Tendeloo G, Desgardin G, European physical journal: applied physics 1, 185 (1998). http://doi.org/10.1051/epjap:1998135
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.684
Times cited: 2
DOI: 10.1051/epjap:1998135
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“Barium-based manganites Ln1-xBaxMnO3 with Ln = {Pr, La}: phase transitions and magnetoresistance properties”. Barnabé, A, Millange F, Maignan A, Hervieu M, Raveau B, Van Tendeloo G, Laffez P, Chem. mater. 10, 252 (1998). http://doi.org/10.1021/cm9704084
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 48
DOI: 10.1021/cm9704084
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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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“Microstructural and physical properties of layered manganite oxides related to the magnetoresistive perovskites”. Laffez P, Van Tendeloo G, Seshadri R, Hervieu M, Martin C, Maignan A, Raveau B, Journal of applied physics 80, 5850 (1996). http://doi.org/10.1063/1.363578
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.183
Times cited: 36
DOI: 10.1063/1.363578
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“Structural phase transition at low temperature, corresponding to charge ordering in the CMR perovskites LN0.5A0.5MNO3”. Laffez P, Van Tendeloo G, Millange F, Caignaert V, Hervieu M, Raveau B, Materials research bulletin 31, 905 (1996). http://doi.org/10.1016/S0025-5408(96)00090-6
Abstract: The magneto resistive perovskites Nd0.5Sr0.5MnO3 and Pr0.5Sr0.41Ca0.09MnO3 undergo a transition from anti ferromagnetic insulator to ferromagnetic metal as function of temperature. The room temperature phase is orthorhombic with the space group Imma and the cell parameters a approximate to root 2a(p), b approximate to 2a(p), and c approximate to root 2a(p). A structural phase transition related to charge ordering accompanying the transition from ferromagnetic state to antiferromagnetic state has been evidenced by low temperature electron diffraction. This transition is reversible and a new superstructure, with a P-type orthorhombic cell. and lattice parameters parameters a approximate to 2 root 2a(p), b approximate to 2a(p), and c approximate to root 2a(p), is formed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.288
Times cited: 25
DOI: 10.1016/S0025-5408(96)00090-6
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