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Showing 1 to 16 of 16 for “"Perowskit"”.
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Austausch von Silizium durch die dreiwertigen Kationen von Eisen und Aluminium in CaSiO3-Perowskiten: Mechanismen und Auswirkungen auf die Mineralogie der Übergangszone
… auf die strukturellen Eigenschaften von CaSiO3-Perowskit als auch die daraus resultierenden Auswirkungen auf den Erdmantel abschätzen zu können, sind Hochdruck- Hochtemperaturexperimente in den beiden Systemen CaSiO3 – CaFeO2,5 und CaSiO3 – CaAlO2,5 bei Drücken zwischen 3 und 25 GPa und …
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Existenzbereiche und physikalische Eigenschaften metallreicher Perowskite (SE3X)M (SE = Seltenerd-Metall; X = N, O; M = Al, Ga, In, Sn)
Die Existenz metallreicher Perowskite der Zusammensetzung (SE3X)M (X = O, N; SE = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Er, Ho, Tm, Lu; M = Al, Ga, In, Sn) wurde untersucht. Die Charakterisierung der Proben erfolgte mit Röntgenpulverdiffraktometrie und Elementaranalysen (O und N). Oxide (SE3O)Al mit SE = …
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Synthese und Charakterisierung von Bismut(III)-basierten Halbleitern ausgehend von homo- und heterometallischen Bismutoxidoclustern
… wird u.a. eine neue Verbindung vom doppelten Perowskit-Strukturtyp erhalten. Die neuartigen Bismutoxidoiodidcluster werden durch die kontrollierte thermische Zersetzung in verschiedene Bismut(III)-oxidiodide überführt. Die erhaltenen Bismut(III)-basierten Halbleiter eignen sich für den …
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Sauerstofftransport und Degradationsverhalten von Hochtemperaturmembranen für CO 2-freie Kraftwerke
This thesis deals with membranes for oxygen separation from air for high temperature application in fossil power plants within the scope of the oxyfuel-process. Different perovskite membrane materials (ABO3-d) were investigated concerning the oxygen transport and their chemical stability under …
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Ultrafast lattice dynamics in photoexcited nanostructures : femtosecond X-ray diffraction with optimized evaluation schemes
Within the course of this thesis, I have investigated the complex interplay between electron and lattice dynamics in nanostructures of perovskite oxides. Femtosecond hard X-ray pulses were utilized to probe the evolution of atomic rearrangement directly, which is driven by ultrafast optical …
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Photon-assisted spectroscopy of electronic interface states in perovskite oxide heterostructures
Complex oxides are an intriguing field of solid-state research, as they can exhibit a wide variety of functional properties, such as ferroelasticity, ferroelectricity, ferro- and antiferromagnetism or an even more complicated type of magnetic ordering, the combination or interaction of those …
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Atomistic simulations for material processes within multiscale method
Atomistic simulation technique such as first-principles, molecular dynamics and Monte Carlo methods has been recognised as a powerful engineering tool to design a new functional material. It serves as the most fundamental procedure to construct a reliable and integral multiscale simulation …
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Strukturelle und elektronische Untersuchungen am hoch sauerstoffdefizitären Mischleiter Ba x Sr 1-x Co 0,8 Fe 0,2 O 3-delta (BSCF)
Oxides of the perovskite structure as BSCF are well known for their ability to accommodate large deviations from the ideal stoichiometry of a perovskite ABO3. This leads to many interesting properties of these materials, such as superconductivity and high oxygen permeability, whereas these …
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Charakterisierung perowskitischer Hochtemperaturmembranen zur Sauerstoffbereitstellung für fossil gefeuerte Kraftwerksprozesse
In this thesis thermochemical properties of mixed conducting, perovskite-type materials were investigated. Those materials are assumed to be applicable as gas separation membranes in the oxyfuel process. Here, the materials should produce the required oxygen more energy-efficient than cryogenic air …
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Pyroelektrische Materialien
Zur Messung pyrelektrischer Koeffzienten wurde ein Messplatz nach einem erweiterten SHARP-GARN-Verfahren entwickelt und zur Untersuchung von Phasenumwandlungen in Pyroelektrika eingesetzt. Einerseits konnten pyroelektrische Messungen im elektrischen Feld die Pyroelektrizität einer neuen durch …
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High throughput methods for synthesis and impedance characterisation of ABO3 gas sensing materials
This PhD thesis deals with the preparation and characterisation of resistive thick-film gas sensors by use of high throughput impedance spectroscopy. Since the 1960s semiconducting resistive gas sensors are used in a wide range of applications. However, commercial systems show disadavantages which …
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Oxygen permeation and thermo-chemical stability of oxygen separation membrane materials for the oxyfuel process
The reduction of CO2 emissions, generally held to be one of the most significant contributors to global warming, is a major technological issue. CO2 Capture and Storage (CCS) techniques applied to large stationary sources such as coal-fired power plants could efficiently contribute to the global …
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Microstructure evolution and crystallisation kinetics of pure and isovalently substituted lead titanate thin films derived by chemical solution deposition
Electroceramic thin films are an essential component in modern technologies of many kinds. In this regard, perovskite materials based on lead titanate (PbTiO3) are especially relevant as functional layers in piezoelectric, ferroelectric, pyroelectric, and other devices. The industrially most …
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Spectroscopic perspectives on ultrafast coupling phenomena in perovskite oxides
In this thesis, I study ultrafast dynamics in perovskite oxides using time resolved broadband spectroscopy. I focus on the observation of coherent phonon propagation by time resolved Brillouin scattering: following the excition of metal transducer films with a femtosecond infrared pump pulse, …