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630 results on '"Blanchard, N"'

162. Planar17ONMR study ofPryY1−yBa2Cu3O6+x

Author

MacFarlane, W. A., primary, Bobroff, J., additional, Mendels, P., additional, Cyrot, L., additional, Alloul, H., additional, Blanchard, N., additional, Collin, G., additional, and Marucco, J.-F., additional

Published
2002
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167. Antiferromagnetism in water doped YBa2Cu3O6+x for x∼0.5

Author

MacFarlane, W.A, primary, Mendels, P, additional, Bobroff, J, additional, Dooglav, A.V, additional, Egorov, A.V, additional, Alloul, H, additional, Blanchard, N, additional, Collin, G, additional, Picard, P.G, additional, Keren, A, additional, King, P.J.C, additional, and Lord, J, additional

Published
2000
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172. Conjugation of TEM-EDX and optical spectroscopy tools for the localization of Yb3+, Er3+ and Co2+ dopants in laser glass ceramics composed of MgAl2O4 spinel nano-crystals embedded in SiO2 glass

Author

Boulon, G., Alombert-Goget, G., Guyot, Y., Guzik, M., Epicier, T., Blanchard, N. P., Chen, L., Hu, L., and Chen, W.

Abstract

The main goal of this work is to conjugate two independent techniques of TEM-EDX and optical spectroscopy, which is rare, for the localization of Yb3+ and Er3+ rare earth ions and Co2+ transition metal ions as dopants in a compact self-Q-switched microchip laser glass ceramic composed of MgAl2O4 spinel nano-crystals of 10–20 nm size embedded in SiO2 glass. The use of the TEM-EDX technique associated with both the elemental mapping of each dopant and the direct visualization of the heavier rare earth ions has led to the result that Er3+ and Yb3+ rare earth ions are preferentially located in the spinel nano-crystals. Regarding the low Co2+ concentration this technique was not accurate enough for characterization and finally we have used absorption spectroscopy to probe the main presence of Co2+ ions in the spinel nano-crystals. The use of Yb3+ ions as structural probes allows the identification of the 0-phonon broad line at 977 nm as both that of the disordered glass and that of the spinel inverted phases. A new Yb3+ radiationless center has been pointed out by the presence of a strong absorption line at 970 nm which has been assigned to the strongly perturbed area of the spinel nano-crystallite surface. This dopant characterization is worthwhile to be shown as a special case where characterization of rare earth and transition metal ions needs the use of both TEM and spectroscopic techniques. [ABSTRACT FROM AUTHOR]

Published
2014
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175. Antiferromagnetism in hydrated 123 compounds

Author

Dooglav, A. V., primary, Egorov, A. V., additional, Mukhamedshin, I. R., additional, Savinkov, A. V., additional, Alloul, H., additional, Bobroff, J., additional, MacFarlane, W. A., additional, Mendels, P., additional, Collin, G., additional, Blanchard, N., additional, and Picard, P. G., additional

Published
1999
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178. Bobroffet al.Reply

Author

Bobroff, J., primary, Alloul, H., additional, Yoshinari, Y., additional, Keren, A., additional, Mendels, P., additional, Blanchard, N., additional, Collin, G., additional, and Marucco, J. F., additional

Published
1998
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182. Experimental demonstration of tokamak fuelling by compact toroid injection

Author

Raman, R, primary, Martin, F, additional, Haddad, E, additional, St-Onge, M, additional, Abel, G, additional, Cote, C, additional, Richard, N, additional, Blanchard, N, additional, Mai, H.H, additional, Quirion, B, additional, LaChambre, J.-L, additional, Gauvreau, J.-L, additional, Pacher, G.W, additional, DeCoste, R, additional, Gierszewski, P.J, additional, Hwang, D.Q, additional, Hirose, A, additional, Savoie, S, additional, LeBlanc, B.-J, additional, McLean, H, additional, Xiao, C, additional, Stansfield, B.L, additional, Cote, A, additional, Michaud, D, additional, and Chartre, M, additional

Published
1997
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194. Dynamics and distribution of doped holes in the CuO2 plane of slightly doped antiferromagnetic YBa2(Cu1 − zLi z)3O6 + x ( x < 0.1) studied by Cu(1) NQR.

Author

Savinkov, A. V., Dooglav, A. V., Alloul, H., Mendels, P., Bobroff, J., Collin, G., and Blanchard, N.

Subjects
NUCLEAR quadrupole resonance, ANTIFERROMAGNETISM, COULOMB potential, PROPERTIES of matter, ELECTRIC fields
Abstract

Incidence of doped holes in the CuO2 plane on the AF state was studied by Cu(1) nuclear quadrupole resonance (NQR) in slightly doped YBa2(Cu1 − zLi z)3O6 + x compounds. Inhomogeneous distribution of doped holes in the plane was detected in the low temperature measurements of transverse (1/ T2) and longitudinal (1/ T1) relaxation rates. We establish that at lower T the holes motion slows down and we estimate that the holes localize finally in restricted regions (∼3 lattice constants) in the Coulomb potential of the Li+ ions. Also we compared the hole behavior in slightly doped YBa2(Cu1 − zLi z)3O6 + x samples with that in slightly doped Y1 − yCa yBa2Cu3O6. A stronger trapping potential of the in-plane Li+ impurities was concluded as compared to slightly doped Y1 − yCa yBa2Cu3O6 compound with out-of-plane Ca2+ impurities. [ABSTRACT FROM AUTHOR]

Published
2010
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196. Ga-NMR local susceptibility of the Kagome-based magnet SrCr[sub 9p] Ga[sub 12–9p] O[sub 19] : A high-temperature study.

Author

Limot, L., Mendels, P., Collin, G., Mondelli, C., Mutka, H., and Blanchard, N.

Subjects
ANTIFERROMAGNETISM, CHROMIUM, HIGH temperatures, MAGNETIC properties
Abstract

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2001
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197. Crystal and magnetic structures of the oxyphosphates MFePO 5 (M = Fe, Co, Ni, Cu). Analysis of the magnetic ground state in terms of superexchange interactions.

Author

El Khayati, N., Cherkaoui El Moursli, R., Rodríguez-Carvajal, J., André, G., Blanchard, N., Bourée, F., Collin, G., and Roisnel, T.

Abstract

We have studied in detail the crystal and magnetic structures of the oxyphosphates MFePO5 (M: divalent transition metal) using neutron powder diffraction as a function of temperature. All of them are isomorphic to the mixed valence compound α-Fe2PO5 with space-group Pnma. No disorder exists between the two metallic sites. The M2+O6 octahedra share edges between them and faces with Fe3+O6 octahedra building zigzag chains running parallel to the b-axis that are connected by PO4 tetrahedra. The topology of this structure gives rise to a complex pattern of super-exchange interactions responsible of the observed antiferromagnetic order. The magnetic structures are all collinear with the spin directed along the b-axis except for M = Co. The experimental magnetic moments of Cu+2 and Ni2+ correspond to the expected ionic value, on the contrary the magnetic moment of Fe3+ is reduced, probably due to covalence effects, and that of Co2+ is greater than the spin-only value indicating a non negligible orbital contribution. Using numerical calculations we have established a magnetic phase diagram adapted for this type of crystal structure and determined the constraints to be satisfied by the values of the exchange interactions in order to obtain the observed magnetic structure as the ground state. [ABSTRACT FROM AUTHOR]

Published
2001
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199. Stereoselective Synthesis of Polypropionate Units and Heterocyclic Compounds by Cyclopropylcarbinol Ring-Opening with Mercury(II) Salts

Author

Meyer, C., Blanchard, N., Defosseux, M., and Cossy, J.

Abstract

The mercury(II)-mediated electrophilic ring-opening reaction of various cyclopropylcarbinol derivatives bearing adjacent stereocenters and a remote nucleophilic functional group provides a useful strategy for synthesizing compounds bearing several contiguous stereocenters. These highly diastereoselective reactions occur with anchimeric assistance by the internal nucleophilic moiety and afford synthetically valuable building blocks such as polypropionate units or heterocyclic compounds. The application of cyclopropylcarbinol ring-opening for the preparation of functionalized oxygen heterocycles in natural product synthesis is also outlined.

Published
2003

200. Total Synthesis of Zincophorin Methyl Ester

Author

Defosseux, M., Blanchard, N., Meyer, C., and Cossy, J.

Abstract

A convergent total synthesis of the methyl ester of zincophorin, an ionophore antibiotic, has been realized relying on a diastereoselective titanium-mediated aldol coupling between the C1−C12 and C13−C25 subunits. The latter fragment was prepared by using a Carroll−Claisen rearrangement.

Published
2003

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