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Showing 1 to 20 of 27 for “"Complex oxides"”.
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Heteroepitaxial Interfaces Modify Collective States in Complex Oxides
Complex oxides exhibit a wide range of collective phenomena in isostructural phases. Titanates and manganites are two examples where various members of their groups have close enough lattice constants that strained superlattices involving both kinds of materials grow epitaxially. In this work …
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Energy transfer processes in the solid solutions of complex oxides
Käesoleva doktoritöö peamiseks eesmärgiks oli näidata kuidas muutused boraatide, fosfaatide ja vanadaatide segukristallide koostises mõjutavad nende struktuurseid, elektroonseid ja optilisi omadusi (erilise tähelepanu all olid lisandamata ja Eu3+ või Ce3+ ioonidega lisandatud LuxY1-xBO3, …
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Study of Functional Complex Oxides at High Pressure-Temperature Conditions
Complex oxides are a diverse family of functional materials whose stability and transformations under extreme conditions are central to chemistry, energy research, and the design of novel compounds. This dissertation focuses on lithium cobalt oxyfluoride (Li2CoO2F), a Li-rich disordered rock-salt …
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Crystal Growth, Structure Determination and Physical Property of Complex Oxides
… setup. Novel Fe, Co, Rh, Hf and Ln containing oxides have been synthesized from molten hydroxide fluxes. Their crystal structures were solved by single crystal X-ray diffraction, and their magnetic and electrical properties have been studied. Unconventional magnetism was found in the new …
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Neutron Scattering Studies of Unusual Spin Structure and Local Correlation in Complex Oxides
Complex correlated electron materials (CEMs), such as transition-metal oxides with exotic properties and novel functionalities, present immense opportunities and formidable challenges in condensed matter physics, materials science, and engineering. These systems are characterized by a multitude of …
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Complex oxides of the system Cu-Ni-Fe-O: synthesis parameters, phase formation and properties
This thesis describes the convenient routes and the preparation conditions (temperature, oxygen partial presssure) which lead to the formation of single phase materials within the quaternary system Cu-Ni-Fe-O. The investigated compositions are the solid solutions CuxNi1-xFe2O4, the ferrites …
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Materials For Energy: Complex Oxides And Nitrides For New Polymer Electrolyte Membrane Fuel Cell Catalysts And Supports
… group has focused on doped, conducting metal oxides, yet materials with suitable conductivities have been difficult to prepare. In this work, binary and ternary transition metal nitrides are explored as potential replacements for carbon-based catalyst supports. Many nitrides have the required …
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Materials Discovery by Crystal Growth: Synthesis, Structure Determination and Physical Properties of Complex Oxides of Niobium, Tantalum, Iron and Uranium
… on discovering new materials, specifically oxides, where the process is being fine tuned to yield compounds with unusual or enhanced physical properties. While the traditional solid-state method is very practical for the preparation of large quantities of materials, the high temperature …
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A study of internal oxidation in carburising steels
… in the free energy of formation of the various oxides types. The observed morphology of the internal oxidation zone at different carburised exposure time, in range of 0.25-16.6h, related to the penetration depth and density of the internal oxides in the internal oxidation zone, with particular …
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Lead-free piezoelectric transducers for vibration based energy harvesting devices
… films that may also be suitable for other complex oxides.
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Theoretical study of polar complex oxide heterostructures
… wide range of physical properties exhibited in complex oxides make them an attractive option for scientific investigation and device applications. Interfaces between these oxides can introduce novel phenomena absent in the bulk of each material. An example is the electrically conducting …
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Surface Engineering and Characterization of Laser Deposited Metallic Biomaterials
… the corrosion product exhibited the presence of complex oxides which are responsible for the excellent corrosion resistance. In addition, the in vitro tests done on LENS deposited TNZT showed that they have excellent biocompatibility. In order to improve the wear resistance of the TNZT system …
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Computational investigation of the thermal conductivities and phonon properties of strontium cobalt oxides
… of electrochemically tuned strontium cobalt oxides (SCO) are significantly different among the perovskite SrCoO3 (P-SCO), the brownmillerite SrCoO2.5 (BM-SCO) and the hydrogenated HSrCoO2.5 (H-SCO)1. The underlying mechanism causing this large difference is still unclear. And phonon …
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Von molekularen Precursoren zu Oxidphasen im System V2O5 / Nb2O5. Darstellung, Eigenschaften, katalytische Aktivität
In this work, mixed alkoxides of general formula [V(O)Nbx(OR)(3+5x)] (R = n-C3H7 and C2H5, x = 1, 4.5 and 9) are obtained. They are used to prepare complex (V/Nb)-pentoxides. Different spectroscopic methods, for example UV/VIS, resonance raman, infrared, temperature dependant 51V NMR and two …
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Probing spin, charge and lattice coupling in manganites
Complex oxides such as the manganites exhibit an intimate coupling of the electron spin, charge and lattice degrees of freedom. The characteristic feature of these materials is the existence of a ground state topology with many closely lying minima. The system can be switched from one minimum to …
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Advanced characterizations of austenitic oxide dispersion-strengthened (ODS) steels for high-temperature reactor applications
… including multiple Y-Ti-O, Y-Al-O, and Y-Ti-Hf-O complex oxides, were observed to form during mechanical alloying. Small precipitates are likely to have coherent or cubic-on-cubic orientation relationships with the matrix, allowing the dislocation to shear through. The Orowan looping mechanism is …
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Cation Site Occupancy and Defect Engineering in Perovskite Heterostructures
Complex oxide thin films and their heterostructures are quintessential materials for next-generation multiferroic and magnetoelectric devices. Cation and anion point defects collectively affect the structural, electrical, and magnetic properties of complex oxides. At the same time, such defects …
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Template Directed Growth of Nb doped SrTiO₃ using Pulsed Laser Deposition
… range of physical properties. Recently, doped complex oxides have drawn considerable attention for various applications including thermoelectrics. Doped complex oxide materials have high Seebeck coefficients (S) and electrical conductivities (o) comparable to other doped semiconductors but low …
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Nanoscale Engineering for Mixed-Dimensional Heterostructure Growth and Integration
… range of materials including III-Vs, III-Ns, and complex-oxides, which in general outperforms 2D counterparts in material properties, can be considered as a building block to form heterogeneous stacks. However, remote epitaxy is still in infancy to work universally for all material systems and all …
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Templated self-assembly of multiferroic nanocomposites
… conventional planar processing is increasingly complex and resource-intensive. Potential replacement materials include complex oxides, which exhibit interesting physical phenomena such as superconductivity, colossal magnetoresistance and multiferroicity. New functionalities are especially found …
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