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Showing 1 to 20 of 39 for “"Pyrochlore"”.
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The synthesis and characterisation of pyrochlore frameworks
… studies have been undertaken on a wide range of pyrochlore phases, with a<br/>focus on garnering a better understanding of the factors determining the formation and<br/>behavior of these materials. Extensive structural characterisation has been undertaken<br/>primarily using powder X-ray and …
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Crystallographic origins of fast-ion conduction in pyrochlore
… of fast-ion conduction in oxides with the pyrochlore structure-type, ideally A2B2O7, a superstructure of (A,B)20 3.5 defect fluorite-like array. These materials have technological promise for use in electrochemical devices such as oxygen sensors and solid-oxide fuel-cells. The pathway for …
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Synthesis, structure and properties of heavy metal pyrochlore oxides
… twenty years in the family of the heavy metal pyrochlore oxides, A2B2O6O’. In<br/>these systems, competing interactions are common and tend to emerge mainly at low<br/>temperatures. Magnetic properties are related to the contribution of d orbitals that transition<br/>metal (TM) offer and their …
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Study on the surface chemistry behavior of pyrochlore during froth flotation
Separation of pyrochlore from its associated minerals is typically accomplished by froth flotation. The surface chemistry of pyrochlore is similar to many of its associated non-value minerals. Therefore, understanding the surface chemical properties of the pyrochlore for selective pyrochlore …
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Applications of CO2 in CO2-responsive foams and pyrochlore froth flotation
… and (2) the use of CO2 as a pH modifier in pyrochlore flotation. The first project is a study of foams generated with the conventional surfactant tetradecyltrimethylammonium bromide C14TAB in the presence of the CO2-switchable additive N,N,-dimethylethanolamine (DMEA) or …
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DISORDERING IN PYROCHLORE PHASES FOR RADIONUCLIDES DISPOSAL: A MULTISCALE STRUCTURE STUDY
Oxides with the general formula A2B2O7 and the pyrochlore structure have drawn much attention in the field of radionuclides immobilization. The Gd2Zr2O7 composition, in particular, has demonstrated high radiation resistance, making it an ideal host-matrix for encapsulating radioactive elements …
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Pyrochlore spin ice Dy2Ti2O7: Investigating a platform for magnetic monopolar quasiparticles
… lowest experimentally measured temperatures. The pyrochlore oxide dysprosium titanate (Dy2Ti2O7) supports a spin ice state on its tetrahedral sublattice of dysprosium spins at low temperatures. Such tetrahedral arrangements of Ising spins yield have drawn interest from the scientific community not …
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Mixed ionic-electronic conduction in rare earth titanate/zirconate pyrochlore compounds
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.
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Development of new pyrochlore-type electrocatalysts for oxygen evolution reaction in acid
… enhanced catalytic performance. Specifically, pyrochlore-type ruthenium (Ru) and iridium (Ir) based catalysts were synthesized and characterized for their OER performance. Introducing yttrium (Y) in these pyrochlores increased the overall activity and stability. To explain this behavior, X-ray …
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Wonderland of frustration: Magnetic moments and itinerant electrons on the pyrochlore lattice
… of frustration in magnetic systems on the pyrochlore lattice, looking at both the conventional frustrated magnetism as well as a less studied form of frustration known as kinetic frustration. We start at half-filling, where the magnetic moments in a Mott insulator are localised and interact …
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Iron Modified Bismuth Titanate Pyrochlore Photocatalysts for Environmental Remediation and Solar Fuel Production
… chapter we examine the catalytic activity of a pyrochlore phase bismuth titanate (Bi2Ti2O7-BTO) in driving the photo-assisted decomposition of a model pollutant, methyl orange (MO). The photoactivity of the BTO was probed with the inclusion of Fe with BTO and with the addition of a co-catalyst- …
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Defect chemistry and electrical properties of ruthenium- and bismuth-substituted gadolinium titanate pyrochlore
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1995.
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Mixed conduction and defect chemistry of manganese and molybdenum substituted gadolinium titanate pyrochlore
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1999.
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Synthesis, cation distribution, and disorder of fast-ion conducting pyrochlore oxides : a combined neutron and X-ray Rietveld analysis
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1999.
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In-situ measurements of the Liquid-Phase Sintering of Zinc Oxide
… of the oxygen fugacity on sintering. Sb2O4, pyrochlore, trirutile and spinel were formed at temperatures of 500°C to 800°C. The oxidation of antimony was controlled by the oxygen partial pressure and affected both, phase formation and sintering kinetics, in the ZBS system. There are three …
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Constraint analysis of radiation-induced amorphizability of zirconate- and titanate-based nuclear wasteforms
Pyrochlores have long been a target of researchers looking for ceramic materials that remain stable under high doses of radiation. However, its constituent atoms have a drastic effect on how stable the structure is. The focus of this paper is to explain how titanate pyrochlores are on average an …
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Systematics of bond length and radii variations in fluoride and silicate molecules and crystals
… material and the doping amount. Furthermore, the pyrochlore to perovskite phase transformation of PZT on RuO₂ electrodes was also investigated. It was shown that PZT films (Zr/Ti=50/50) with 10 at.% excess lead annealed at 650°C for 30 min possessed the best electrical properties for ferroelectric …
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Electrical properties of doped and undoped PZT thin films prepared by a sol-gel method
… and the doping amount. Furthermore, the pyrochlore to perovskite phase transformation of PZT on RuO₂ electrodes was also investigated. It was shown that PZT films (Zr/Ti=50/50) with 10 at.% excess lead annealed at 650°C for 30 min possessed the best electrical properties for ferroelectric …
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Sol-gel processing, perovskite phase development and properties of relaxor-based thin layer ferroelectrics
… were amorphous, and formed a nonferroelectric pyrochlore phase or a ferroelectric perovskite phase, depending on the processing route. Since the perovskite structure is required for ferroelectric properties, the phase development and processing methods for perovskite formation were investigated …
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Magnetotransport of connected artificial spin ice
… systems like spin ice, a class of magnetic pyrochlore oxides. Here I detail measurements of the magnetotransport response of connected artificial spin ice to varying temperatures and magnetic fields. In the literature, transport measurements have been used simply as a tool to probe the …
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