Sökning: "Fasta tillståndets fysik"

Visar resultat 21 - 25 av 241 avhandlingar innehållade orden Fasta tillståndets fysik.

  1. 21. Magnetization Dynamics in Ferromagnetic Thin Films : Evaluation of Different Contributions to Damping in Co2FeAl and FeCo Film Structures

    Författare :Serkan Akansel; Peter Svedlindh; Olof Karis; Erik Wahlström; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spintronics; Gilbert damping parameter; magnetization dynamics; ferromagnetic resonance; Heusler alloys; magnetic thin films; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : Static and dynamic magnetic properties of Co2FeAl and Fe65Co35 alloys have been investigated. Co2FeAl films were deposited at different temperatures and the deposition parameters were optimized with respect to structural and magnetic properties. As a result, a film with B2 crystalline phase was obtained without any post-annealing process. LÄS MER

  3. 22. Electronic and magnetic properties of Tsai quasicrystals and their approximants under pressure

    Författare :Fernand Denoel; Roland Mathieu; Vassilios Kapaklis; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tsai quasicrystal; high pressure; diamond anvil cell; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : Quasicrystals constitute a special category of crystals exhibiting long-range order without periodicity. This strange feature allows them to exhibit rotational symmetries prohibited in regular crystals, such as 5-, 8-, 10- or 12-fold symmetry. Amongst them, icosahedral quasicrystals are the only type that is aperiodic along all 3 dimensions. LÄS MER

  4. 23. Modelling Band Gap Gradients and Cd-free Buffer Layers in Cu(In,Ga)Se2 Solar Cells

    Författare :Jonas Pettersson; Charlotte Platzer-Björkman; Marika Edoff; Marc Burgelman; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; CIGS; Thin film solar cells; Electrical modelling; Alternative buffer layers; Gallium gradients; Simulations; Electrical characterization; Metastabilities; Light-soaking; Hall measurements; Persistent photoconductivity; Teknisk fysik med inriktning mot elektronik; Engineering Science with specialization in Electronics;

    Sammanfattning : A deeper understanding of Cu(In,Ga)Se2 (CIGS) solar cells is important for the further improvement of these devices. This thesis is focused on the use of electrical modelling as a tool for pursuing this aim. Finished devices and individual layers are characterized and the acquired data are used as input in the simulations. LÄS MER

  5. 24. Thermal Radiation from Co-evaporated Cu(In,Ga)Se2 : End point detection and process control

    Författare :Jens Schöldström; Marika Edoff; Nicolas Barreau; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; CIGS; Cu InGa Se2; thin film; solar cells; end point detection; process control; optical constants; CuxSe; Teknisk fysik med inriktning mot elektronik; Engineering Science with specialization in Electronics;

    Sammanfattning : The use of solar cells for energy production has indeed a bright future. Reduction of cost for fabrication along with increased efficiency are key features for a market boom, both achieved as a result of increased knowledge of the technology. LÄS MER

  7. 25. Fundamental Properties of Functional Magnetic Materials

    Författare :Magnus Wikberg; Peter Svedlindh; Per Nordblad; Klas Gunnarsson; Amílcar Labarta; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic anisotropy; magnetic aging; magnetic semiconductors; exchange interactions; magnetic oxides; spin glasses; lithium-ion batteries; short-range magnetic order; Physics; Fysik; Engineering Science with specialization in Solid State Physics; Teknisk fysik med inriktning mot fasta tillståndets fysik;

    Sammanfattning : Magnetic properties of powders, thin films and single crystals have been investigated using magnetometry methods. This thesis provides analysis and conclusions that are supported by the results obtained from spectroscopic and diffraction measurements as well as from theoretical calculations. LÄS MER