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Accueil du site > Présentation > Production scientifique > Articles publiés sur HAL et TEL > Publications 2010

Publications 2010

1er juin 2011

Piezoelectric Aluminum Nitride Resonator for Oscillator

12 mai 2014

This work investigates properties of the thin film elongation acoustic resonator (TFEAR) operating at megahertz frequencies in air. This resonator is composed of a piezoelec- tric layer of AlN sandwiched between 2 Al electrodes. TFEAR works in the extensional mode excited via AlN d31 (...)

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Magnetic and dielectric properties in the langasite-type compounds: A3BFe3D2O14 (A=Ba,Sr,Ca;B=Ta,Nb,Sb;D=Ge,Si)

10 mai 2014

The Fe-based langasites are the only reported compounds presenting a magnetic ordering in this rich family, besides being well known for piezoelectric properties and optical activity. The structural, magnetic, and dielectric properties of the Fe-langasite compounds, with various substitution of (...)

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Étude des propriétés mécaniques et thermoélectriques des matériaux Ca3Co4O9 texturés pour la conversion d'énergie

17 décembre 2010

L'oxyde thermoélectrique (TE) Ca3Co4O9 se place avantageusement pour les applications de conversion d'énergie en raison de ses bonnes propriétés TE, ses stabilités chimique et thermique à l'air à haute température et l'absence de biotoxicité. Une étude comparative des apports respectifs de procédés de (...)

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Étude des propriétés mécaniques et thermoélectriques des matériaux Ca3Co4O9 texturés pour la conversion d'énergie

17 décembre 2010

L'oxyde thermoélectrique (TE) Ca3Co4O9 se place avantageusement pour les applications de conversion d'énergie en raison de ses bonnes propriétés TE, ses stabilités chimique et thermique à l'air à haute température et l'absence de biotoxicité. Une étude comparative des apports respectifs de procédés de (...)

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Pressure-Induced Structural Transition in LuFe2O4: Towards a New Charge Ordered State

10 décembre 2010

The electronic ferroelectric lutetium ferrite (LuFe2O4) was studied by x-ray diffraction as a function of pressure. Pressure is shown to induce an irreversible rhombohedral to orthorhombic transition leading to a supercell determined by the combination of electron and synchrotron x-ray (...)

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Pressure-Induced Structural Transition in LuFe2O4: Towards a New Charge Ordered State

10 décembre 2010

The electronic ferroelectric lutetium ferrite (LuFe2O4) was studied by x-ray diffraction as a function of pressure. Pressure is shown to induce an irreversible rhombohedral to orthorhombic transition leading to a supercell determined by the combination of electron and synchrotron x-ray (...)

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Elastic and magnetic effects on the infrared phonon spectra of MnF2

3 décembre 2010

We measured the temperature-dependent infrared reflectivity spectra of MnF2 between 4 and 600 K. We show that the phonon spectrum undergoes a clear renormalization at TN. The ab initio calculation we performed on this compound accurately predicts the magnitude and the direction of the changes (...)

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Elastic and magnetic effects on the infrared phonon spectra of MnF2

3 décembre 2010

We measured the temperature-dependent infrared reflectivity spectra of MnF2 between 4 and 600 K. We show that the phonon spectrum undergoes a clear renormalization at TN. The ab initio calculation we performed on this compound accurately predicts the magnitude and the direction of the changes (...)

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Combined Analysis: structure-texture-microstructure-phase-stresses-reflectivity determination by x-ray and neutron scattering

26 octobre 2010

Combined algorithms are now available that make use of various formalisms to treat x-ray and neutron scattering data.

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Combined Analysis: structure-texture-microstructure-phase-stresses-reflectivity determination by x-ray and neutron scattering

26 octobre 2010

Combined algorithms are now available that make use of various formalisms to treat x-ray and neutron scattering data.

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Thermoelectric generator placed on the human body: system modeling and energy conversion improvements

1er octobre 2010

This paper focuses on the production of electricity using a thermoelectric generator placed on the human body connected to a dc-dc converter. The small difference in temperature between the hot heat source (e.g. the human body, Tb = 37 ◦C) and the cold heat source (e.g. ambient air, Ta = 22 ◦C), (...)

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Thermoelectric generator placed on the human body: system modeling and energy conversion improvements

1er octobre 2010

This paper focuses on the production of electricity using a thermoelectric generator placed on the human body connected to a dc-dc converter. The small difference in temperature between the hot heat source (e.g. the human body, Tb = 37 ◦C) and the cold heat source (e.g. ambient air, Ta = 22 ◦C), (...)

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An ab-initio evaluation of the local effective interactions in the $\rm Na_{x} Co O_2$ familly

7 juillet 2010

We used quantum chemical ab initio methods to determine the effective parameters of Hubbard and $t-J$ models for the $\rm Na_xCoO_2$ compounds (x=0 and 0.5). As for the superconducting compound we found the $a_1g$ cobalt orbitals above the $e_g^\prime$ ones by a few hundreds of meV due to the (...)

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An ab-initio evaluation of the local effective interactions in the $\rm Na_{x} Co O_2$ familly

7 juillet 2010

We used quantum chemical ab initio methods to determine the effective parameters of Hubbard and $t-J$ models for the $\rm Na_xCoO_2$ compounds (x=0 and 0.5). As for the superconducting compound we found the $a_1g$ cobalt orbitals above the $e_g^\prime$ ones by a few hundreds of meV due to the (...)

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Large increase of the Curie temperature by orbital ordering control

13 novembre 2009

Using first principle calculations we showed that the Curie temperature of manganites thin films can be increased by far more than an order of magnitude by applying appropriate strains. Our main breakthrough is that the control of the orbital ordering responsible for the spectacular $T_C$ (...)

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Large increase of the Curie temperature by orbital ordering control

13 novembre 2009

Using first principle calculations we showed that the Curie temperature of manganites thin films can be increased by far more than an order of magnitude by applying appropriate strains. Our main breakthrough is that the control of the orbital ordering responsible for the spectacular $T_C$ (...)

Lire la suite

Magnetic and dielectric properties in the langasite-type compounds : A3BFe3D2O14 with A=Ba, Sr, Ca, B=Ta, Nb, Sb and D=Ge, Si

27 mars 2009

The Fe-based langasites are the first reported compounds presenting a magnetic ordering in this rich family, besides being well known for piezo-electric properties and optical activity. The structural, magnetic and dielectric properties of the Fe langasite compounds, with various substitution (...)

Lire la suite

Magnetic and dielectric properties in the langasite-type compounds : A3BFe3D2O14 with A=Ba, Sr, Ca, B=Ta, Nb, Sb and D=Ge, Si

27 mars 2009

The Fe-based langasites are the first reported compounds presenting a magnetic ordering in this rich family, besides being well known for piezo-electric properties and optical activity. The structural, magnetic and dielectric properties of the Fe langasite compounds, with various substitution (...)

Lire la suite