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Visar resultat 11 - 15 av 154 avhandlingar som matchar ovanstående sökkriterier.

  1. 11. Theoretical and Computational Studies on the Physics of Applied Magnetism : Magnetocrystalline Anisotropy of Transition Metal Magnets and Magnetic Effects in Elastic Electron Scattering

    Författare :Alexander Edström; Jan Rusz; Olle Eriksson; Patrick Bruno; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetism; Magnetic anisotropy; DFT; Permanent magnets; Electron vortex beams; Electron microscopy; Electron scattering; Multislice methods; Magnetism; magnetisk anisotropi; permanentmagneter; täthetsfunktionalteori; elektronmikroskopi; elektronvirvelstrålar; elektronspridningsteori; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this thesis, two selected topics in magnetism are studied using theoretical modelling and computational methods. The first of these is the magnetocrystalline anisotropy energy (MAE) of transition metal based magnets. In particular, ways of finding 3d transition metal based materials with large MAE are considered. LÄS MER

  3. 12. Carbon-based magnetic nanomaterials

    Författare :Valeria Zagaynova; Tatiana Makarova; Mauro Ricco; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon nanotube; fullerene; single molecular magnet; Mn12; graphite fluoride; nanoporous carbon; molecular magnetism; magnetic properties; SQUID magnetometry; x-ray diffraction; Raman spectroscopy; Materials Science; materialvetenskap;

    Sammanfattning : Magnetism of carbon-based materials is a challenging area for both fundamental research and possible applications. We present studies of low-dimensional carbon-based magnetic systems (fullerene-diluted molecular magnets, carbon nanotubes, graphite fluoride, and nanoporous carbon) by means of SQUID magnetometer, X-ray diffraction and vibrational spectroscopy, the latter techniques used as complementary instruments to find a correlation between the magnetic behaviour and the structure of the samples. LÄS MER

  4. 13. Effects of Spin-Orbit Interactions in Ferromagnetic Metal Nanoparticles

    Författare :Aleksander Cehovin; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; electrical; magnetic and optical properties; elementary spin excitations; spektroskopi; magnetisk resonans; supraledare; electron tunneling spectroscopy; Condensed matter:electronic structure; magnetic anisotropy; spin-orbit interactions; magnetism in nanostructures; egenskaper elektriska; ferromagnetic materials; magnetiska och optiska ; Kondenserade materiens egenskaper:elektronstruktur; relaxation; spectroscopy; supraconductors; magnetic resonance; Fysicumarkivet A:2003:Cehovin;

    Sammanfattning : This thesis is a theoretical investigation of the effects of spin-orbit (SO) interactions in ferromagnetic metal nano-particles. Part I of the thesis is devoted to an elementary introduction of the research field, including recent experimental advances which partly motivated the work presented here. LÄS MER

  5. 14. Tunable Magnetic Properties of Transition Metal Compounds

    Författare :Solveig Felton; Per Nordblad; Peter Svedlindh; John Chapman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic properties; Transition metal compounds; Magnetic structure; Domain structure; SQUID-magnetometry; MFM; Magnetism; Magnetism;

    Sammanfattning : The magnetic properties of transition metal compounds have been studied using SQUID-magnetometry, magnetic force microscopy and Lorentz transmission electron microscopy. New magnetic materials have been found and their magnetic properties have been determined. How the magnetic properties of a material can be changed through e.g. LÄS MER

  7. 15. Quantum mechanical models of nanomagnetism in transition metal clusters and diluted magnetic semiconductors

    Författare :Olof Strandberg; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diluted magnetic semiconductors; Mn As; Ga; transition metal clusters; magnetic anisotropy; Nanomagnetism; quantum geometric phases; Chern numbers; effective spin Hamiltonians; dimers;

    Sammanfattning : This dissertation investigates nanomagnetism in small transition metal clusters and the diluted magnetic semiconductor (Ga,Mn)As. We derive quantum mechanical models aimed at a realistic description of the low energy physics in these systems. LÄS MER