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Showing 1 to 20 of 34 for “"Anomalous Hall Effect"”.
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Anomalous Hall Effect in Calcium -Doped Lanthanum Cobaltite and Gadolinium
The Hall resistivity, magnetoresistance, and magnetization of a Gadolinium single crystal were measured in fields up to 30 T. Cobaltite films were grown via laser ablation and characterized by a variety of techniques. Hall resistivity, magnetoresistance, magnetization, and magnetothermopower of L …
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Anomalous Hall Effect in Calcium-doped Lanthanum Cobaltite and Gadolinium
Made available in DSpace on 2012-06-28T21:43:37Z (GMT). No. of bitstreams: 1 Baily_Scott.pdf: 3760245 bytes, checksum: 7239169ba2ec52f9b0a9c55d7519bb1e (MD5) Previous issue date: 2003
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Anomalous Hall effect and persistent valley currents in graphene p-n junctions/
Dirac particles can exhibit Hall-like transport induced by Berry's gauge field in the absence of magnetic field. We develop a detailed picture of this unusual effect for charge carriers in graphene nanostructures. The Hall effect is nonzero in each valley but is of opposite signs in different …
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Disorder and Doping in the Oxygenated Electron-doped Superconductor PCCO
… Pr_(2-x)Ce_(x)CuO_(4-delta). I investigated the effects of oxygenation in this material using resistivity and Hall measurements. For various oxygen contents, I was able to determine that there is a separable doping and a disorder contribution to the superconducting transition temperature. I was …
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Interplay between Correlation and Topology in Two-dimensional Systems
… emergent Kondo lattice physics, quantum Hall ferromagnetism, (fractional) quantum anomalous Hall effect, and formation of anomalous Hall crystals. Typically in many of these systems, there is a nearly flat low-energy band with non-zero Berry curvature. This generalizes the familiar …
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Non-collinear spin textures in oxides for spintronics and superconducting spintronics
… as a function of field-cool strength, I see an effective field acting on the softer La0.7Ca0.3MnO3 layer consistent with an anti-ferromagnetic exchange coupling from the SrRuO3. The strength of this coupling varies with the substrate used and essentially disappears when a non-magnetic spacer …
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Spin-Mediated Transport in Superconducting and Spin-Polarized Systems
The effects of spin-imbalance on the electronic transport properties of spin-polarized and superconducting systems have been studied in detail. The transport properties of the quaternary Heusler alloys Co2MnSi1-xAlx (0≤x≤1), which have been theoretically predicted to develop a half-metallic band …
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EMERGENT PHENOMENA AND NOVEL DEVICES BASED ON SPIN-ORBIT COUPLING AT COMPLEX OXIDE INTERFACES
… has been pivotal to this effort as it offers an effective means to drive and manipulate magnetic properties – such as anisotropy, spin relaxation, magnetic damping, anisotropic magnetoresistance, and anomalous Hall effect – allowing it to be exploited for future spin-orbitronics, especially for …
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Investigation of wide bandgap semiconductors for room temperature spintronic, and photovoltaic applications
… mechanism is identified. GaGdN exhibits Anomalous Hall Effect at room temperature if it contains oxygen or carbon atoms but shows Ordinary Hall Effect in their absence. The mechanism for spin and ferromagnetism in GaGdN is a combination of intrinsic, metallic conduction, and …
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Aspects of Moiré Quantum Matter
… discuss directional localization, formation of Hall crystals with tunable Chern numbers, and novel fractional Chern insulator collective mode physics in the context of modulated Landau levels. We also show that a class of models comprising itinerant electrons strongly coupled to skyrmion-like …
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Electromagnetic response of time-reversal breaking metallic phases in two dimensions
… beta phase exhibits nonvanishing un-quantized anomalous Hall effect in the absence of external magnetic fields, which corresponds to the Berry curvature on the Fermi surface. The alpha phase does not have that property. To go beyond the mean-field, we introduce the machinery of higher …
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Magneto-thermal Transport and Machine Learning-assisted Investigation of Magnetic Materials
… its existence. Not limited to these flat band effects, magnetic insulators can assume a variety of nontrivial topologies such as magnetic skyrmions. In this thesis, I investigate the highly frustrated magnetic system Y0.5Ca0.5BaCo4O7, where the kagome lattice could potentially lead to …
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The Electronic Compressibility of Rhombohedral Graphene Multilayers
… the recent discovery of the fractional quantum anomalous Hall effect in this system when the electrons are pushed away from the moiré interface by an external electric displacement field, we study the opposite moiré-proximal limit, in which the superlattice potential is considerably stronger. We …
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Genetic algorithm gradient ascent (GAGA) optimization of compact symmetry-breaking photonic crystals
… absorbers/emitters are simulated and compared – anomalous Hall effect in Weyl semimetals 2 and electric-current-induced Fizeau drag in either Dirac or Weyl semimetals3 . To engineer an ultra-compact absorber structure that does not require gratings or prisms to couple light, a genetic algorithm …
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Pulsed Laser Deposited Iron Garnet Thin Films for Spintronics
… occupies up to 40% of the octahedral Fe sites. Anomalous Hall effect-like spin Hall magnetoresistance measurements were performed to determine the effect of scandium content on spin mixing conductance of the TbScIG|Pt interface. The spin mixing conductance increased significantly with an …
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Topological Phases in Perovskite Iridates with Strong Spin-Orbit Coupling
… model is constructed using the basis of an effective J eff=1/2 pseudo-spins. A topological magnetic insulator with quantum anomalous Hall effect is found in the bilayer superlattice when a magnetic order or magnetic field is present in the system. Lastly, a pair of helical Majorana fermions …
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Scanning tunneling microscopy studies of a tunable topological insulator and magnetic Weyl semimetal
… In Ge(Bix,Sb1-x)2Te4, increasing Sb substitution effectively electron dopes the sample and moves the Dirac point from 300 meV below the Fermi energy to energies above the Fermi energy while remaining topological. As the topological surface states in this material are well isolated from the bulk …
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Phase coherent transport phenomena in HgTe quantum well structures
… a very good template to study spin related effects. It exhibits large Zeeman spin splitting and Rashba spin-orbit splitting. The latter is at least four to five times larger than in III-V semiconductors. Initially a short review on the transport theory was presented. The main focus as on …
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Physics and applications of magnetic interactions in topological insulators
… attention to the study of the magnetic proximity effect, whereby a ferromagnet placed in proximity to a 3D TI creates a mass gap in the Dirac surface states and generates a quantum anomalous Hall effect (QAHE). Although this platform has long been proposed for technological applications ranging …
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First principles and machine learning methods in molecules, fluids, and solids
… cells. Inspired by an unexpected exchange bias effect in topological insulator superlattices, we introduce magnetic models to investigate the doping effect and predict the interfacial coupling between dopants induces exchange bias. We provide a new pathway for achieving the high-temperature …
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