Search for dissertations about: "incommensurate structures"

Showing result 1 - 5 of 14 swedish dissertations containing the words incommensurate structures.

  2. 1. Understanding Physical Reality via Virtual Experiments

    Author : Sergiu Arapan; Rajeev Ahuja; Börje Johansson; Chris Pickard; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; density functional theory; ab initio calculations; electronic structure; lattice dynamics; high-pressure phase transitions; high-temperature phase transitions; incommensurate structures; Condensed matter physics; Kondenserade materiens fysik;

    Abstract : In this thesis I have studied some problems of condensed matter at high pressures and temperatures by means of numerical simulations based on Density Functional Theory (DFT).The stability of MgCO3 and CaCO3 carbonates at the Earth's mantle conditions may play an important role in the global carbon cycle through the subduction of the oceanic crust. READ MORE

  4. 2. Structure studies of some ternary copper chalcogenides

    Author : Lasse Norén; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Ternary copper chalcogenides; Structures; Phase transitions; Disorder; Transformations; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

    Abstract : Copper has in its heavier chalcogenides often a high mobility in the solid state. This behaviour has also be found for some ternary compounds where copper appears to govern the observed phase transitions and structural transformations. READ MORE

  5. 3. Chemical Tuning of the Magnetic Interactions in Layer Structures

    Author : Sabina Ronneteg; Rolf Berger; J. Paul Attfield; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Inorganic chemistry; neutron powder diffraction; magnetometry; layered magnetic structure; incommensurate helical structure; ThCr2Si2 type structure; antiferromagnetism; ferromagnetism; electronic structure calculations; Oorganisk kemi; Inorganic chemistry; Oorganisk kemi;

    Abstract : Thin metal films have found their use in many magnetic devices. They form pseudo two-dimensional systems, where the mechanisms for the magnetic interactions between the layers are not completely understood. READ MORE

  6. 4. Solving Mysteries and Outwitting Transitions : Investigating the Incommensurate Crystal Structures of AuIn and Sn3Sb2

    Author : Laura Folkers; Centrum för analys och syntes; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Crystallography; Modulation; Intermetallics; X-Ray Diffraction; Single crystal;

    Abstract : This thesis introduces two new incommensurate alloys. AuIn shows variable amounts of modulation, depending on the measurement temperature. At 400°C the diffraction pattern shows diffuse scattering and a thallium iodide type Cmcm space group. READ MORE

  7. 5. Modulations in Intermetallic Families of Compounds

    Author : Hanna Lind; Sven Lidin; Gervais Chapuis; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; intermetallic; incommensurate structure; single crystal X-ray diffraction; Inorganic chemistry; Oorganisk kemi;

    Abstract : This thesis is based on a study of five distinct intermetallic systems with the aim of expanding the general knowledge of aperiodically modulated crystal structures. Families of compounds that contain a variety of superstructures together with incommensurately modulated structures have been investigated mainly by means of single crystal X-ray diffraction and higher dimensional structure models. READ MORE