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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"antiferromagnetism"”.
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Massive Short-Range Antiferromagnetism in Copper - Manganese Alloys
Made available in DSpace on 2014-12-14T16:00:32Z (GMT). No. of bitstreams: 1 7709217.pdf: 5348539 bytes, checksum: 6a81b654893627194441d50f6d6eced9 (MD5) Previous issue date: 1976
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Magnetic-field-induced antiferromagnetism in the Kondo lattice
… energy scale, at which point the canted antiferromagnetism is exponentially suppressed and the system crosses over to a nearly-metallic regime. The quantum Monte Carlo simulations are performed using a determinant Monte Carlo method that has been extended to handle mixed spin and …
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Antiferromagnetism, ferromagnetism and magnetic phase separation in Bi₂Sr₂O₆â[delta]
Neutron scattering, magnetization and transport measurements were performed on single crystals of Bi2Sr2CoO6+[delta] to study the evolution of the magnetic properties as a function of the oxygen content . The oxygen content was varied by annealing single crystals in either a reducing or oxidizing …
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On the competition of superconductivity, antiferromagnetism and charge order in the high-Tc compounds
Diese Arbeit läßt sich in zwei grobe Abschnitte gliedern. Der erste Teil umfaßt die Kapitel 1-3, in denen drei verschiedene Konzepte beschrieben werden, die zum Verständis stark korrelierter Vielteilchen-Systeme dienen. Dies sind zunächst einmal die SO(5)-Theorie in Kapitel 3, die den allgemeinen …
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Magnetic Penetration Depth Analysis of Unconventional Superconductors
… with copper. We seek to study the impact of antiferromagnetism and the presence of a quantum critical point on superconductivity. We also seek to characterize the superconductivity and compare to similar materials. Additionally we seek to study how superconductivity arises from novel methods …
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Phase diagram for the S equals one-half and J equals three-halves Kondo lattice model
… are explored. Magnetic phases found include antiferromagnetism, ferromagnetism, and spin-density wave ordering of both commensurate and incommensurate varieties. In S=1/2, the magnetic phase exhibits a spike in critical temperature at half-filling. In J=3/2, the Kondo phase is reentrant at …
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Symmetry breaking in the Hubbard model : a bosonization approach
… interplay of various long range properties as antiferromagnetism and superconductivity, one can calculate the phase diagram of the Hubbard model in the charge density-temperature plane. This analysis is conveniently carried out by means of exact renormalization group equations that we apply in …
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Penetration Depth Studies of Unconventional Superconductors
… presence of another order, such as paramagnetism/antiferromagnetism (in ErNi2B2C) or spin-density-wave (in Pb). We also see how the superfluid response is modified by nonlocal corrections in CeCoIn5 and Sr2RuO4. Hints of multi-band superconductivity are seen in YNi2B2C, LuNi2B2C and Sr2RuO4. …
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Emergence of charge density wave domain walls above the superconducting dome in TiSe2
… the vicinity of another ordered state, such as antiferromagnetism, charge density wave (CDW), or stripe order. This suggests a fundamental connection between SC and fluctuations in some other order parameter. 1T-TiSe2 is a prototypical CDW material in the transtion-metal dichalcogenide family …
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Topics in the Theory of High-Temperature Superconductors
… an understanding of the relationship between antiferromagnetism and superconductivity as well as an understanding of the nature of the pseudogap will be essential to the development of a theory for the cuprate superconductors. In this Thesis we propose experimental tests aimed at assessing the …
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Anistropic phenomena in strongly correlated electron systems
… may be represented consistently. The extent of antiferromagnetism is determined; phases are discovered where the Fermi surface consists of small hole pockets, and the Mott transition happens as these pockets shrink to points. Anisotropic phenomena observed in the cuprates are reproduced by the …
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The Electronic Compressibility of Rhombohedral Graphene Multilayers
… including half and quarter metals, layer antiferromagnetism, correlation-driven Chern insulators, and thermodynamic signatures of potential Wigner crystallization. We also study the electronic compressibility of R5G aligned to a hexagonal boron nitride (hBN) substrate to form a moiré …
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Electrical and magnetic properties of organic semiconductors: Electrical conductivity and electron spin resonance studies of semiconducting, organic, charge transfer salts.
… are discussed in terms of Heisenberg antiferromagnetism and Pauli paramagnetism. In Chapter V temperature dependent behaviour of electrical conductivity is discussed in terms of an exciton band model, the lattice structure of the salts and one-dimensional lattice consisting of defects …
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Structural and Magnetic Phases in Pressure-Tuned Quantum Materials
… into the metallic phase, with long range antiferromagnetism giving way to a previously unobserved short-range order. This work is relevant on a broader scale for numerous layered magnetic materials such as cuprate high temperature superconductors. Secondly, pressure is used to explore the …
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Coexistence and Competition of Superconductivity and Magnetism
… both isotropic superconductivity and itinerant antiferromagnetism. Firstly, a free energy approximation is derived to study the behaviour near the critical temperatures of the two phenomena. This is followed by an examination of the phase diagram at lower temperatures. A novel phase is found …
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Dzyaloshinskii-Moriya Interaction and Local Exchange Variation in Rare-Earth Transition-Metal Ferrimagnets
… alignment and gives rise to ferromagnetism and antiferromagnetism, the DMI favors canting of spins perpendicular to its neighbors. While DMI has been extensively studied in ferromagnetic systems, little work has been done to quantify its strength in ferrimagnetic systems. In this thesis the …
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High-Pressure Studies of Some Heavy Fermion Materials
… effective mass and antiferromagnetic order. Antiferromagnetism can be suppressed to a quantum critical point around 30 kbar, where there exists a dome of superconductivity with Tc ≈ 0.2 K. Chapter 3 focuses on this superconducting phase, which has a large upper critical field, exceeding the …
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Non-equilibrium dynamics of dipole-coupled internal states in cold gases
… spin configurations, such as spin density waves, antiferromagnetism and long-time oscillations, as well as bistabilities between these phases. To assess the validity of the mean-field approximation, we compare our mean-field results to small quantum systems. We carry out a similar analysis on a …
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Low-dimensional and frustrated magnetism in complex lanthanide oxides
… Neutron diffraction revealed long-range antiferromagnetism in TbTaO4 while the remaining compounds do not order above 1.8 K. This thesis reports previously unexplored fundamental magnetic properties of several different lanthanide materials, demonstrating the rich variety of magnetic …
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Slave particle study of the strongly correlated electrons
… wide range of phenomena from ferromagnetism and antiferromagnetism to the conventional superconductivity. However, in the last thirty years, many experiments including the fractional quantum Hall effect (QHE) have revolutionized our view of nature. For a system of electrons that is subject to a …
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