Global ETD Search
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 13 of 13 for “"magnetic phase transition"”.
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Aspects of quantum criticality in itinerant electron ferromagnetic systems
… systems that exhibit a zero temperature magnetic phase transition. This thesis is mainly concerned with such quantum critical points and is an investigation into the various phenomena seen in the phase diagram of itinerant ferromagnetic systems. We apply a standard theory of itinerant …
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Quantum Transport and Electric-Field Effects in Layered Topological Semimetals and Magnetic Materials
… nodal line topological semimetals and antiferromagnetic materials down to a few layers. We used gate-induced effects to alter the transport properties of these materials. </p> <p>First, we introduced current annealing in topological semimetals to achieve high-quality devices. We demonstrate …
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Demagnetisation of solid 3He and supercritical superflow
… solid 3He will be used to search for a possible magnetic phase transition as well as to study superfluid 3He virtually free of quasiparticle excitations. The work reports progress to the present state of the experiment and discusses setbacks due to a large unexpected heating which appeared during …
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Preparation and Characterization of Solid Solutions of Ternary and Quaternary Antimony Oxides
This thesis is primary aiming to study the phase transition of ternary antimony oxide systems induced by temperature change and chemical modification. The beamline diffraction techniques, including synchrotron and neutron powder and single crystal diffraction techniques were employed as major …
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Inelastic light scattering studies of quantum phase transitions in CuxTiSe2 and multiferroic TbMnO3
… are used to probe the temperature- and magnetic-field-induced phase transitions of two strongly correlated systems – the magnetoelectric multiferroic TbMnO3 and the layered dichalcogenide TiSe2 . In general, strongly correlated materials have a strong coupling between charge, spin, …
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The study of weak ferromagnetism by andreev reflection spin spectroscopy and development of bimorph electro-thermal actuators
… ferromagnet MnSi changes as it undergoes magnetic phase transition from helical to conical to induced ferromagnetic. Also, unconventional conductance with enhanced Andreev reflection with amplitude more than two, and conductance oscillations outside superconducting gap indicate the …
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Thermal expansion and magnetostriction studies on iron pnictides
… The lattice effects at the structural and the magnetic phase transition have been investigated and the phase diagram upon F-doping has been studied. A main result is the observation of a previously unknown fluctuation regime for the doping level $\mathnormal{x}\leqslant$ 0.04 over a large $T$ …
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Exploring the Stochastic Performance of Metallic Microstructures With Multi-Scale Models
… of microstructure-property relationships to magnetic materials to investigate the ferromagnetic-paramagnetic phase transition. Here, the same Ising model-based multi-scale approach used for microstructure reconstruction is implemented for investigating the ferromagnetic-paramagnetic phase …
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Optimization of Materials for Magnetic Refrigeration and Thermomagnetic Power Generation
<p>The magnetocaloric effect, by which a magnetic material experiences a change in temperature due to an applied magnetic field, can be used for refrigeration. The corollary to the magnetocaloric effect -- known as the pyromagnetic effect -- is the phenomenon by which a magnetic material …
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Peculiarities of crystal and magnetic structures of synthetic Co-olivine, Co 2 SiO 4
… there is still a lack of information on the magnetic properties and the thermal evolution of the crystal structure below room temperature for some olivines. One of the less studied olivine-type silicates is the synthetic cobalt olivine, Co2SiO4. The main goal of the present study is to …
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Molecular-based magnets constructed from cyanometalate building blocks
… preparation of molecular-based magnets with high magnetic ordering temperatures: they can be easily prepared from well-characterized cyanometalate building blocks, the metal centers are linked covalently into a 3D network, and a wide range of metals with different spin states and oxidation states …
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Magnetic domain walls in ultrathin films : contribution of the Dzyaloshinsky-Moriya interaction
In this theoretical thesis the structure of magnetic domain walls is explained by an interplay of spin stiffness, anisotropy energy and Dzyaloshinsky-Moriya interaction. The wall structures are discussed within a micromagnetic model and the corresponding model parameters are obtained ab initio by …
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Electrical resistivity of YbRh2Si2 and EuT2Ge2 (T = Co, Cu) at extreme conditions of pressure and temperature
… levels. At T_N = 70 mK, YbRh2Si2 undergoes a magnetic phase transition. Upon applying pressure up to p_1 = 4 GPa , T_N increases monotonously while the peak in the electrical resistivity is shifted to lower temperatures. For p < p_1 a different behavior is observed; namely, T_N depends …