Search for dissertations about: "Magnetic phase transitions"

Showing result 1 - 5 of 62 swedish dissertations containing the words Magnetic phase transitions.

2. 1. Phase transitions in magnetic metamaterials

   Author : Björn Erik Skovdal; Björgvin Hjörvarsson; Vassilios Kapaklis; Gunnar K. Pálsson; Peter Schiffer; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetic metamaterials; artificial spin ice; mesospins; magnetic nanostructures; mesoscopic spin systems; multiscale materials; tri-criticality; emergence; edge modes;

   Abstract : Magnetic metamaterials consisting of arrays of densely packed, two-dimensional nanoscale magnetic islands have degrees of freedom on two separate length scales: inside the islands, and among them. These degrees of freedom can be tuned by e.g. size, shape, island separation and lattice geometry. READ MORE

4. 2. Phase transitions in high-temperature superconductors

   Author : Jack Lidmar; KTH; []
   Keywords : Superconductivity; Vortices; Phase transitions; Strongly correlated fermions; High-temperature superconductivity; Monte Carlo simulations.; TECHNOLOGY; TEKNIKVETENSKAP;

   Abstract : Thermal fluctuations and disorder strongly influence the behaviour of hightemperature superconductors. In particular the vortices play a key role in determining their properties. In this thesis the main focus lies on phase transitions, both in ultra-thin films and in three-dimensional systems, which are driven by vortex fluctuations. READ MORE

5. 3. Topological Phase Transitions in Magnetic Nanostructures of Dirac Materials

   Author : Nezhat Pournaghavi; Carlo M. Canali; Michael Flatté; Linnéuniversitetet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Topological insulators; Magnetic materials; Quantum anomalous Hall effect; Topological magneto electric effect; Dirac semimetals; Weyl semimetals; Condensed Matter Physics; Kondenserade materians fysik;

   Abstract : Over the past two decades, the discovery of topological Dirac materials, such as topological insulators and semimetals, has defined a new paradigm in condensed matter physics and established new platforms for realizing spin electronic devices and quantum computing. The novel quantum properties of these materials, which are mainly due to the presence of strong spin-orbit coupling, are invariant under topological transformations, making them more resilient to structural disorder, electromagnetic and thermal fluctuations in comparison to the conventional silicon-based materials. READ MORE

6. 4. Magnetic Ordering in Layered Magnets

   Author : Moreno Marcellini; Björgvin Hjörvarsson; Roger C.C Ward; Uppsala universitet; []
   Keywords : Physics; Magnetic thin films and superlattices; Magnetic phase transitions; Polarized neutron reflectometry; Fysik;

   Abstract : The preparation of layered magnets needs the knowledge of growth techniques which are focused on the growth of Fe/V(001) superlattices. Such films have been structurally investigated by X-rays reflectivity and diffraction. READ MORE

7. 5. Critical Phenomena and Exchange Coupling in Magnetic Heterostructures

   Author : Martina Ahlberg; Gabriella Andersson; Björgvin Hjörvarsson; Steve Bramwell; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; phase transitions; critical behavior; 2D XY model; MOKE; magnetic thin films and superlattices; amorphous multilayers; magnetic proximity effects; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Abstract : The continuous phase transition in thin magnetic films and superlattices has been studied using the magneto-optical Kerr effect (MOKE) and polarized neutron scattering (PNR).  It has been shown that the critical behavior of amorphous thin films belonging to the 2D XY universality class can be described within the same theory as crystalline sample. READ MORE