The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Philippe Sainctavit - One of the best experts on this subject based on the ideXlab platform.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism
Physical Review B, 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron $(\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Fe})$ nanoparticles, with average sizes ranging from 5 to $13\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, are embedded in a nanocrystalline oxide matrix composed of both magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ and maghemite $(\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3})$. These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a $2--3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism.
Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron (alpha-Fe) nanoparticles, with average sizes ranging from 5 to 13 nm, are embedded in a nanocrystalline oxide matrix composed of both magnetite (Fe3O4) and maghemite (gamma-Fe2O3). These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a 2–3 nm-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
Luca Signorini - One of the best experts on this subject based on the ideXlab platform.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism
Physical Review B, 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron $(\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Fe})$ nanoparticles, with average sizes ranging from 5 to $13\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, are embedded in a nanocrystalline oxide matrix composed of both magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ and maghemite $(\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3})$. These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a $2--3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism.
Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron (alpha-Fe) nanoparticles, with average sizes ranging from 5 to 13 nm, are embedded in a nanocrystalline oxide matrix composed of both magnetite (Fe3O4) and maghemite (gamma-Fe2O3). These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a 2–3 nm-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
Pierre Laszlo - One of the best experts on this subject based on the ideXlab platform.
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theory of nuclear spin relaxation in heterogeneous media and application to the cross correlation between quadrupolar and dipolar fluctuations of deuterons in clay gels
Journal of Magnetic Resonance, 1992Co-Authors: D Petit, Jean Grandjean, Pierre Laszlo, Jeanpierre Korb, A DelvilleAbstract:Abstract The fictitious-spin - 1 2 operator formalism allows a comprehensive study of the longitudinal and transverse nuclear relaxations of a nuclear spin I = 1 in heterogeneous media, in the presence of a residual time-averaged quadrupolar interaction. An extension of this formalism makes possible the calculation of the cross correlation between the quadrupolar and dipolar (paraMagnetic) fluctuations. Although this cross correlation is second order relative to the quadrupolar relaxation, its long range of effectiveness ( ∞ 1 r 3 ) is sufficient to provide the sole asymmetric component to the fine broadening of the deuterium doublet. This differential line broadening depends linearly on the applied Magnetic Induction Field and on the paraMagnetic spin concentration, as checked experimentally from a lineshape analysis of the 2H doublet observed for D20 in clay gels. The reorientational correlation time of the adsorbed water at the clay interface is obtained from the measured 2H spin-relaxation rates.
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Order acquisition by clay platelets in a Magnetic Field. NMR study of the structure and microdynamics of the adsorbed water layer
The Journal of Physical Chemistry, 1991Co-Authors: Alfred Delville, Jean Grandjean, Pierre LaszloAbstract:Suspensions of the Ecca Gum BP bentonite in heavy water are oriented by the Magnetic Induction Field in the probe of an NMR spectrometer. Ordering of the clay platelets is a slow (minutes to hours) cooperative process. It gives rise to residual quadrupolar splittings for 2 H and 17 O nuclei within the water solvent. Binary mixtures of D 2 O with acetonitrile-d 3 , acetone-d 6 , dimethyl-d 6 sulfoxide, and methanol-d 4 likewise display splittings of the CD 3 deuteron resonance, from the orientation of the clay particles in the magnet
Luca Pasquini - One of the best experts on this subject based on the ideXlab platform.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism
Physical Review B, 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron $(\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Fe})$ nanoparticles, with average sizes ranging from 5 to $13\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, are embedded in a nanocrystalline oxide matrix composed of both magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ and maghemite $(\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3})$. These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a $2--3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism.
Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron (alpha-Fe) nanoparticles, with average sizes ranging from 5 to 13 nm, are embedded in a nanocrystalline oxide matrix composed of both magnetite (Fe3O4) and maghemite (gamma-Fe2O3). These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a 2–3 nm-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
Federico Boscherini - One of the best experts on this subject based on the ideXlab platform.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism
Physical Review B, 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron $(\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Fe})$ nanoparticles, with average sizes ranging from 5 to $13\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, are embedded in a nanocrystalline oxide matrix composed of both magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ and maghemite $(\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3})$. These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a $2--3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
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Local magnetism in granular iron/iron oxide nanostructures by phase- and site-selective x-ray Magnetic circular dichroism.
Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2006Co-Authors: Luca Signorini, Luca Pasquini, Federico Boscherini, Ennio Bonetti, Isabelle Letard, Sandrine Brice-profeta, Philippe SainctavitAbstract:We present a study of the local Magnetic properties of iron/iron oxide granular nanostructures by x-ray Magnetic circular dichroism (XMCD). Metallic iron (alpha-Fe) nanoparticles, with average sizes ranging from 5 to 13 nm, are embedded in a nanocrystalline oxide matrix composed of both magnetite (Fe3O4) and maghemite (gamma-Fe2O3). These granular samples were synthesized by cold compacting core-shell nanoparticles, in which a 2–3 nm-thick oxide layer surrounds the iron particles, synthesized by inert gas condensation. By exploiting the chemical selectivity and site sensitivity of XMCD, we were able to separate the Magnetic contributions of the metallic core and of the two oxide phases present in the matrix and to study their behavior as a function of iron particle size and applied Magnetic Induction Field. We detected the presence of a significant spin canting, predominantly affecting the octahedral sites of Fe in the oxide phase, and studied its dependence on the degree of structural disorder and applied Magnetic Induction Field.
