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Your search keyword '"Casanove, M. -J"' showing total 13 results
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13 results on '"Casanove, M. -J"'

1. Electronic conductivity and structural distortion at the interface between insulators SrTiO3 and LaAlO3

Author

Maurice, J. -L., Carretero, C., Casanove, M. -J., Bouzehouane, K., Guyard, S., Larquet, É., and Contour, J. -P.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

When insulator LaAlO3 is grown by epitaxy onto a TiO2-terminated {100} surface of insulator SrTiO3, the resulting system has a metallic character. This phenomenon has been associated with an electrostatic frustration at the interface, as {100} surfaces of SrTiO3 are neutral while those of LaAlO3 are polar, but its microscopic mechanism is not quite understood. Here, we present a structural characterisation of this interface by aberration-corrected transmission electron microscopy. The unit cells at the interface appear elongated: we discuss this distortion in terms of electrostatic charge and extra carriers at the interface.

Published
2005
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2. Factors influencing orientations of covalently-attached and doped aromatic groups in stretched polyethylene films

Author

Wang, Caihua, Xu, Jinqi, Weiss, Richard G., Fromen, M.-C., Lecante, P., Casanove, M.-J., and Respaud, M.

Subjects
Aromatic compounds -- Research, Aromatic compounds -- Chemical properties, Aromatic compounds -- Optical properties, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

The utility of comparing orientational parameters from doped and covalently attached groups in analyzing the factors responsible for stretch-induced orientation is demonstrated with the results. There are significant differences between the orientations of doped and covalently attached groups of the same type due to the inability of the latter to translocate between site types during film stretching.

Published
2003

3. Synthesis of zeolitic mesoporous by dry gel conversion under controlled humidity

Author

Naik, Sajo P., Chiang, Anthony S.T., Thompson, R.W., Fromen, M.-C., Respaud, M., Lecante, P., and Casanove, M.-J.

Subjects
Zeolites -- Research, Zeolites -- Chemical properties, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

Vacuum-dried precursor gels could be converted to zeolite by water vapor even below saturation conditions. The effects of precursor preparation and surfactant flocculation conditions on mesoporosity and crystallinity of the final product, as well as the steam stability of the product, are investigated.

Published
2003

4. Synthesis and magnetism of CoxRh(sub 1-x) and CoxRu(sub 1-x) nanoparticles

Author

Zitoun, D., Amiens, C., Chaudret, B., Fromen, M.-C., Lecante, P., Casanove, M.-J., and Respaud, M.

Subjects
Ruthenium -- Research, Ruthenium -- Magnetic properties, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

The synthesis of CoxRh(sub 1-x) and CoxRu(sub 1-x) alloys of nanometric size dispersed in a polymer matrix through the simultaneous decomposition of the organometallic precursors in solution in mild conditions is described. These structural studies enable to find some analogies between three CoM systems (M= Ru, Rh, Pt).

Published
2003

5. Nanoscale bimetallic CoxPt1-x particles dispersed in poly(vinylpyrrolidone): synthesis from organometallic precursors and characterization

Author

Ely, T. Ould, Pan, Cheng, Amiens, C., Chaudret, B., Dassenoy, F., Lecante, P., Casanove, M.-J., Mosset, A., Broto, J.-M., and Respaud, M.

Subjects
Laminated metals -- Research, Organometallic chemistry -- Research, Chemicals, plastics and rubber industries
Abstract

It has been possible to demonstrate the synthesis of CoxPt1-x particles of nanometric size dispersed in an inert organic matrix through the simultaneous decomposition of the organometallic precursors Co(eta3-C8H13)(eta4-C8H12) and Pt2(dba)3 in solution in mild conditions.

Published
2000

11. Nanoscale Bimetallic Co<INF>x</INF><INF></INF>Pt<INF>1</INF><INF>-</INF><INF>x</INF><INF></INF> Particles Dispersed in Poly(vinylpyrrolidone): Synthesis from Organometallic Precursors and Characterization

Author

Ely, T. O., Pan, C., Amiens, C., Chaudret, B., Dassenoy, F., Lecante, P., Casanove, M.-J., Mosset, A., Respaud, M., and Broto, J.-M.

Abstract

The reaction of Co(η3-C8H13)(η4-C8H12) and Pt2(dba)3 (dba = bis-dibenzylidene acetone) under dihydrogen leads in the presence of poly(vinylpyrrolidone) to nanometric bimetallic particles CoxPt1-x. The composition of the material is determined by the initial ratio of the two organometallic precursors. The bimetallic character of the particles is evidenced by magnetic, structural, and spectroscopic studies. Structural changes are evidenced both by HREM and WAXS:  platinum rich particles adopt a fcc crystalline structure while cobalt rich particles adopt a non periodic polytetraedral arrangement. The magnetic properties of the materials have been investigated. ZFC/FC measurements show that the particles are superparamagnetic and that their size dispersity is very low. From isothermal magnetization measurements, the extrapolated value of the coercive field HC (T = 0) is shown to increase continuously with Pt concentration, which is characteristic of bimetallic particles.

Published
2000

12. A New Synthetic Method toward Bimetallic Ruthenium Platinum Nanoparticles; Composition Induced Structural Changes

Author

Pan, C., Dassenoy, F., Philippot, K., Amiens, C., Lecante, P., Mosset, A., Casanove, M.-J., and Chaudret, B.

Abstract

The reaction of Pt(dba)2 with Ru(COD)(COT) in various proportions under dihydrogen in the presence of PVP leads to the formation of bimetallic nanoparticles of definite compositions resulting from the relative concentration of the two complexes in the initial solution. The progressive incorporation of ruthenium into the platinum matrix leads to structural changes from face-centered cubic (fcc) for high platinum contents to hexagonal close-packed (hcp) for high ruthenium contents. For the composition Pt1Ru3 a contraction of the size of the particles (ca. 1.1 nm) and of the size distribution indicates the presence of a new phase consisting of monodisperse particles for which a model of truncated twinned octahedrons of 79 atoms was proposed.

Published
1999

13. Inhomogeneous spatial distribution of the magnetic transition in an iron-rhodium thin film.

Author

Gatel C, Warot-Fonrose B, Biziere N, Rodríguez LA, Reyes D, Cours R, Castiella M, and Casanove MJ

Abstract

Monitoring a magnetic state using thermal or electrical activation is mandatory for the development of new magnetic devices, for instance in heat or electrically assisted magnetic recording or room-temperature memory resistor. Compounds such as FeRh, which undergoes a magnetic transition from an antiferromagnetic state to a ferromagnetic state around 100 °C, are thus highly desirable. However, the mechanisms involved in the transition are still under debate. Here we use in situ heating and cooling electron holography to quantitatively map at the nanometre scale the magnetization of a cross-sectional FeRh thin film through the antiferromagnetic-ferromagnetic transition. Our results provide a direct observation of an inhomogeneous spatial distribution of the transition temperature along the growth direction. Most interestingly, a regular spacing of the ferromagnetic domains nucleated upon monitoring of the transition is also observed. Beyond these findings on the fundamental transition mechanisms, our work also brings insights for in operando analysis of magnetic devices.

Published
2017
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