Sökning: "Magnetic order"

Visar resultat 11 - 15 av 637 avhandlingar innehållade orden Magnetic order.

  1. 11. Modeling and Verification of Ultra-Fast Electro-Mechanical Actuators for HVDC Breakers

    Författare :Ara Bissal; Göran Engdahl; Elena Lomonova; KTH; []
    Nyckelord :Actuators; Armature; Capacitors; Circuit breakers; Coils; Damping; Eddy currents; Elasticity; Electro-mechanical devices; Electromagnetic forces; Finite element methods; HVDC transmission; Image motion analysis; Magnetic domains; Magnetic flux; Magnetic forces; Magnetic materials; Magnets; Thermal analysis; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : The continuously increasing demand for clean renewable energy has rekindled interest in multi-terminal high voltage direct current (HVDC) grids. Although such grids have several advantages and a great potential, their materialization has been thwarted due to the absence of HVDC breakers. LÄS MER

  3. 12. Designing order with long-range interactions in mesoscopic magnetic chains

    Författare :Christina Vantaraki; Vassilios Kapaklis; Björgvin Hjörvarsson; Gabriella Andersson; Tapati Sarkar; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magnetism; mesospins; mesoscopic magnetic chains; magnetic nanostructures; long-range interactions;

    Sammanfattning : This thesis investigates how the low-energy magnetic configuration of a mesoscopic chain can be tuned by geometrical modifications. The magnetic arrays made by single-domain stadium shaped elements positioned side-by-side were fabricated by patterning into a sputtered ferromagnetic thin film. LÄS MER

  4. 13. The Effect of Long Range Order on Elastic Properties of Alloys

    Författare :Guisheng Wang; Levente Vitos; Balázs Ujfalussy; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; long-range order; elastic constant; alloys; magnetic; Industriell ekonomi och organisation; Industrial Engineering and Management;

    Sammanfattning : Ab initio alloy theory, formulated within the exact muffin-tin orbitals method in combination with the coherent-potential approximation, is used to determine the effect of long range order on the elastic properties. The lattice parameters and single-crystal elastic constants of Cu3Au are calculated for different partially ordered structures ranging from the fully ordered L12 to the random face centered cubic lattice. LÄS MER

  5. 14. Engineering Magnetic Droplets in Nanocontact Spin-Torque Nano-Oscillators

    Författare :Sheng Jiang; Johan Åkerman; Dario Arena; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic Droplet; Magnetic Tunnel Junction; Perpendicular Magnetic Anisotropy; Spin-torque Nano-Oscillators; Spin-Valve.; Physics; Fysik;

    Sammanfattning : Spin-torque nano-oscillators (STNOs) are nanoscale spintronic devices capable of generating highly tunable broadband microwave signals. In this thesis, I study nanocontact (NC)-based STNOs using strong perpendicular magnetic anisotropy(PMA) free layers, where a novel magnetic soliton—a magnetic droplet—exists. LÄS MER

  7. 15. 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