0000000000877785

AUTHOR

G. Pourroy

showing 4 related works from this author

Novel metallic iron/manganese-zinc ferrite nanocomposites prepared by microwave hydrothermal flash synthesis

2011

8 Caillot, T. Pourroy, G. Stuerga, D.; Metallic iron (alpha-Fe)/manganese-zinc ferrite (Fe3-x-yMnxZnyO4) nanocomposites have been successfully synthesized for the first time using microwave hydrothermal treatment of alcoholic solutions of chloride precursors and sodium ethoxide. This new type of nanocomposites, never obtained by conventional synthesis, can now be produced in a short period (e.g. 15s). The powders were characterized by X-ray diffraction, transmission electron microscopy and magnetic properties were measured. In most cases, three classes of crystallites were observed; one of them is composed of grains of about 100 nm in size where the metal is inserted into the oxide. For all…

Materials scienceInorganic chemistryOxideNanoparticlechemistry.chemical_element02 engineering and technologyZinc01 natural sciencesHydrothermal circulationMetalchemistry.chemical_compound0103 physical sciencesMaterials ChemistryHydrothermal synthesis010302 applied physicsMechanical EngineeringMetals and Alloys[CHIM.CATA]Chemical Sciences/Catalysis021001 nanoscience & nanotechnology[SDE.ES]Environmental Sciences/Environmental and SocietychemistryMechanics of Materialsvisual_artvisual_art.visual_art_mediumFerrite (magnet)Crystallite0210 nano-technologyNuclear chemistry
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Magnetic exchange interactions in the heteropoly complexes [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)]

1990

The magnetic properties of the heteropolyanions [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)] down to 4 K are reported. Their individual heteropoly molecules contain a rhomblike arrangement formed by four coplanar MO6 octahedra sharing edges. The magnetic properties support an intramolecular ferromagnetic exchange in the Co(II) tetramer, and antiferromagnetic exchange in the Cu(II) tetramer. These behaviors are discussed assuming anisotropic exchange in the Co(II) compound, and Heisenberg exchange in the Cu(II) compound. Carlos.Gomez@uv.es

Magnetic PropertiesExchange InteractionsGeneral Physics and AstronomyCopper ComplexesAntiferromagnetismTetramerVery Low TemperatureAntiferromagnetismMoleculeAnisotropy:FÍSICA::Química física [UNESCO]Cobalt Complexes ; Copper Complexes ; Heteropolyanions ; Magnetic Properties ; Exchange Interactions ; Ferromagnetism ; Antiferromagnetism ; Anisotropy ; Heisenberg Model ; Ultralow Temperature ; Very Low TemperatureCondensed matter physicsChemistryHeisenberg modelUltralow TemperatureUNESCO::FÍSICA::Química físicaCrystallographyOctahedronFerromagnetismIntramolecular forceFerromagnetismHeisenberg ModelAnisotropyCobalt ComplexesHeteropolyanions
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Microwave hydrothermal flash synthesis of nanocomposites Fe–Co alloy/cobalt ferrite

2004

Abstract The present article presents, for the first time, the last developments reported for an original microwave hydrothermal flash synthesis of Fe–Co alloys (FeyCo1−y)/cobalt ferrite (Fe3−xCoxO4) nanocomposites. Synthesis was performed in alcoholic solutions of ferrous chloride, cobalt chloride and sodium ethoxide (EtONa) using a microwave autoclave (The RAMO system) specially designed by authors. Compared with conventional synthesis, smaller grains (100 nm compared to 1 μm) can be produced in a short period (e.g. 10 s) using a less basic medium. In all the cases, the microstructure and the amount of metal inside the composite particles are very different from the product obtained via a…

Materials scienceSodium ethoxideAlloyMetallurgyengineering.materialCondensed Matter PhysicsMicrostructureChlorideHydrothermal circulationElectronic Optical and Magnetic MaterialsAutoclaveInorganic Chemistrychemistry.chemical_compoundChemical engineeringchemistryMaterials ChemistryCeramics and CompositesengineeringmedicineHydrothermal synthesisPhysical and Theoretical ChemistryMicrowavemedicine.drugJournal of Solid State Chemistry
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Mixed‐valence trinuclear manganese clusters : Influence of the electronic transfer on the magnetic properties

1990

The magnetic behavior of mixed‐valence trinuclear clusters d4‐d4‐d5 is discussed on the basis of a model which takes into account valence delocalization and Heisenberg exchange. This model considers the competing effect between the electronic transfer and the localization of the extra electron due to an asymmetry of the triangular entity. The magnetic properties of the mixed‐valence oxo‐centered Mn(II)‐Mn(III)‐Mn(III) complexes formulated as Mn3O(O2CR)6L3 (R=Me, L=pyridine) are discussed on the basis of the developed model, supporting a significant intramolecular electron transfer. A comparison of these results to those previously reported by assuming a valence‐trapped model is given. Carlo…

Valence (chemistry)ChemistryMagnetic Propertiesmedia_common.quotation_subjectUNESCO::FÍSICAExchange InteractionsGeneral Physics and Astronomychemistry.chemical_elementManganeseElectronElectron TransferManganese ComplexesAsymmetryElectron transferCrystallographyDelocalized electronchemistry.chemical_compound:FÍSICA [UNESCO]Intramolecular forcePyridineMixed−Valence CompoundsAtomic ClustersAtomic physicsMixed−Valence Compounds ; Electron Transfer ; Magnetic Properties ; Atomic Clusters ; Manganese Complexes ; Exchange Interactionsmedia_common
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