نتایج جستجو برای: spinel structure
تعداد نتایج: 1570753 فیلتر نتایج به سال:
Introduction: The discovery of spinel rich rock on the Earth’s Moon, detected by the M near-IR mapping spectrometer on the Chandrayaan-1 spacecraft [1] is among the most intriguing discoveries in a time filled with lunar revelations (e.g., [2]). The M spectrometer discerned several areas on the rim of the far-side Moscoviense basin which had near-IR reflectance spectra characteristic of abundan...
The magnetic properties of calcined cobalt ferrite formed by nano-crystalline powders have been compared by two different methods (co-precipitation and hydrothermal). The structural properties of the produced powders were investigated by X-ray Diffraction (XRD), scanning electron microscopy (SEM). The results show that the formation of cobalt ferrite spinel structures is effected by changing me...
Binary transition metal oxides have been regarded as one of the most promising candidates for high-performance electrodes in energy storage devices, since they can offer high electrochemical activity and high capacity. Rational designing nanosized metal oxide/carbon composite architectures has been proven to be an effective way to improve the electrochemical performance. In this work, the (Co,M...
Self-assembled epitaxial BiFeO3-MgO and BiFeO3-MgAl2O4 nanocomposite thin films were grown on SrTiO3 substrates by pulsed laser deposition. A two-phase columnar structure was observed for BiFeO3-MgO codeposition within a small window of growth parameters, in which the pillars consisted of a magnetic spinel phase (Mg,Fe)3O4 within a BiFeO3 matrix, similar to the growth of BiFeO3-MgFe2O4 nanocomp...
Zn1-x Ni x O (x = 0.03 ÷ 0.10) and Zn1-x Fe x O (x = 0.03 ÷ 0.15) thin films were synthesized by sol-gel method. The structure and the surface morphology of zinc oxide thin films doped with transition metal (TM) ions have been investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). The magnetic studies were done using vibrating sample magnetometer (VSM) at room temperature. E...
Cobalt-containing metal oxides [perovskites (LaCoO(3), NdCoO(3), YCoO(3), La(0.7)Sr(0.3)CoO(3)), spinel (Co(3)O(4)) and wolframite (CoWO(4))] have been examined as catalysts for photocatalytic water oxidation with Na(2)S(2)O(8) and [Ru(bpy)(3)](2+) as an electron acceptor and a photosensitizer, respectively. Catalysts with the perovskite structure exhibited higher catalytic activity as compared...
across) and UI-21 (1.5 cm across). UI-3 is a websterite, composed of augite (gray), orthopyroxene (white) and spinel (brown); at the top is the host basalt. UI-21 is a spinel lherzolite; spinel is brown, other phases near-white. MINERALOGY DETERMINATIONS BY CHEMIN XRD, TESTED ON ULTRAMAFIC ROCKS (MANTLE XENOLITHS). A. H. Treiman, K. L. Robinson, D. F. Blake, and D. Bish. Lunar and Planetary Ins...
Nanostructured Cu(x)Zn(1-x)Al(2)O(4) with a Cu:Zn ratio of ¼:¾ has been prepared by a microwave-assisted hydrothermal synthesis at 150 °C and used as a precursor for Cu/ZnO/Al(2)O(3)-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m(2) g(-1)). Cu nanoparticles of an average size of 3.3 nm can be formed by reduct...
We report on the intriguing evolution of the dynamical spin correlations of the frustrated spinel ZnMn2O4. Inelastic neutron scattering and magnetization studies reveal that the dynamical correlations at high temperatures are 1D. At lower temperature, these dynamical correlations become 2D. Surprisingly, the dynamical correlations condense into a quasi 2D Ising-like ordered state, making this a...
Nanocrystalline nickel ferrite (NiFe2O4) has been synthesized from a stoichiometric mixture of oxides NiO and α-Fe2O3 in a high energy planetary mill. A post milling annealing at 350 °C was used to improve the solid state reaction. The obtained powders were investigated by X-ray diffraction, magnetic measurements, scanning electron microscopy, X-ray microanalysis, differential scanning calorime...
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