Sökning: "Ising model"

Visar resultat 21 - 25 av 31 avhandlingar innehållade orden Ising model.

  1. 21. Anisotropy, disorder and frustration in magnetic nanoparticle systems and spin glasses

    Författare :Petra Jönsson; Eric Vincent; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Materialvetenskap; Materials science; Teknisk materialvetenskap; Solid State Physics; fasta tillståndets fysik;

    Sammanfattning : Magnetic properties of nanoparticle systems and spin glasses have been investigated theoretically, and experimentally by squid magnetometry.Two model three-dimensional spin glasses have been studied: a long-range Ag(11 at% Mn) Heisenberg spin glass and a short-range Fe0.5Mn0.5TiO3 Ising spin glass. LÄS MER

  3. 22. Criticality and Frustration: Classical and Quantum Spin Models in Two Dimensions

    Författare :Per Fröjdh; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : We investigate two-dimensional spin models and begin with an introduction to critical phenomena with emphasis on classical systems with boundaries and conformal invariance. Then we introduce the antiferromagnetic quantum Heisenberg model with frustrating interactions. LÄS MER

  4. 23. Magnetic materials with tunable thermal, electrical, and dynamic properties : An experimental study of magnetocaloric, multiferroic, and spin-glass materials

    Författare :Matthias Hudl; Per Nordblad; DD Sarma; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetocalorics; multiferroics; spin glasses; magnetization; polarization; spin-dimensionality; Fasta tillståndets fysik; Solid State Physics;

    Sammanfattning : This thesis concerns and combines the results of experimental studies of magnetocaloric, multiferroic and spin-glass materials, using SQUID magnetometry as the main characteriza-tion technique. The magnetocaloric effect offers an interesting new technology for cooling and heating applications. LÄS MER

  5. 24. A Random Walk in Statistical Physics

    Författare :Pontus Svensson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis deals with some aspects of the physics of disordered systems. It consists of four papers and an introductory part. An introduction, suitable for physicists, to theoretical computer science and computational complexity is contained in chapter 2. LÄS MER

  7. 25. Dynamics in magnetic metamaterials

    Författare :Agnė Čiučiulkaitė; Vassilios Kapaklis; Gabriella Andersson; Björgvin Hjörvarsson; Will Branford; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Metamaterials are artificially created structures with properties that are not found in nature. They can be tailored to achieve desired response to external excitations such as external electric and magnetic fields, as well as to enhance materials’ optical or magnetic activity. LÄS MER