Sökning: "Gunnar K. Pálsson"

Hittade 4 avhandlingar innehållade orden Gunnar K. Pálsson.

  1. 1. The effect of nano-confinement on hydrogen uptake in metallic superlattices

    Författare :Sotirios A. Droulias; Max Wolff; Gunnar K. Pálsson; Björgvin Hjörvarsson; Daniel Azofeifa; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The absorption of hydrogen is exothermic in vanadium whereas it is endothermic in iron and chromium. Investigations of the hydrogen uptake within Fe/V(001) and Cr/V(001) superlattices allow therefore a detailed exploration of finite size effects and the influence of boundaries on hydrogen absorption. LÄS MER

  3. 2. Order and interfaces in epitaxial heterostructures : Structure and magnetism

    Författare :Anna L. Ravensburg; Vassilios Kapaklis; Björgvin Hjörvarsson; Gunnar K. Pálsson; Martina Müller; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The work in this dissertation is devoted to investigating order and interfaces in epitaxial heterostructures. To achieve that the software tool box GenL was developed for simulating and fitting x-ray diffraction patterns from epitaxial thin films, which is used to access structural information on the length scales of interfaces and atomic bonds. LÄS MER

  4. 3. Phase transitions in magnetic metamaterials

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

    Sammanfattning : 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. LÄS MER

  5. 4. Influence of Self-trapping, Clamping and Confinement on Hydrogen Absorption

    Författare :Gunnar Karl Pálsson; Björgvin Hjörvarsson; Keith Ross; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hydrogen diffusion; thin films; superlattices; phase transitions; confinement; clamping; self-trapping; finite-size effect; Surfaces and interfaces; Ytor och mellanytor; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The dissociation of hydrogen molecules at surfaces is the first step in the absorption process. If the absorbing material is covered by an oxide, this layer will determine the effective uptake rate of an underlying absorbing material. LÄS MER