Sökning: "quasicrystal approximants"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden quasicrystal approximants.

  1. 1. Syntheses, structure determination, magnetic and thermoelectric properties of quasicrystal approximants in RE-Au-SM systems (RE = Gd, Tb and Yb and SM = Si, Ge)

    Författare :Girma Hailu Gebresenbut; Cesar Gomez; Martin Sahlberg; Torbjörn Gustafsson; Lars Eriksson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quasicrystals; quasicrystal approximants; thermoelectric properties; magnetic properties; Materialvetenskap; Materials Science;

    Sammanfattning : In this study, new compositions of Tsai-type 1/1 quasicrystal approximants Gd(14)Au(70)Si(16), Gd(14)Au(67)Ge(19), Tb(14)Au(70)Si(16) and Yb(16)Au(65)Ge(19)are synthesized using both self-flux and arc-melting-annealing techniques. Both syntheses routes resulted single phase samples. LÄS MER

  3. 2. Complexity of quasicrystal approximants —The RECd6 and RE13(Zn/Cd)~58 systems

    Författare :ShuYing Piao; Sven Lidin; Osamu Terasaki; Marc de Boissieu; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Rare-earth; Quasicrystal approximant; order and disorder; Chemistry; Kemi; oorganisk kemi; Inorganic Chemistry;

    Sammanfattning : This thesis is focused on the synthesis and structural determination of a series of quasicrystal approximants in the RE13Zn~58 (RE = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu), Ce13Cd~58 and RECd6 (RE = Tb, Ho, Er, Tm and Lu) systems. Structural studies were performed by single crystal X-ray diffraction methods. LÄS MER

  4. 3. Quasicrystal Approximants in the RE-Au-SM systems (RE = Gd, Tb, Ho, Yb; SM = Si, Ge) : Syntheses, structures and properties

    Författare :Girma Hailu Gebresenbut; Cesar Pay Gómez; Martin Sahlberg; Torbjörn Gustafsson; Alan I. Goldman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Quasicrystal approximant; structure; physical property; Chemistry with specialization in Inorganic Chemistry; Kemi med inriktning mot oorganisk kemi; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this study, new Tsai-type 1/1 quasicrystal approximants (ACs) in the RE-Au-SM systems (RE = Gd, Tb, Ho, Yb; SM = Si, Ge) were synthesized using high temperature synthesis techniques such as self-flux, arc-melting-annealing and novel arc-melting-self-flux methods. The syntheses not only provided appropriate samples for the intended structural and physical property measurements but could also be adapted to other systems, especially where crystal growth is a challenge. LÄS MER

  5. 4. 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

  7. 5. Al-based Thin Film Quasicrystals and Approximants

    Författare :Simon Olsson; Fredrik Eriksson; Lars Hultman; Jensen Jens; Xiaodong Zou; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : In this work, Al-based quasicrystalline and approximant phases have been synthesized in thin films using magnetron sputter deposition. Quasicrystals are structures having long-range order and rotational symmetries which are inconsistent with periodicity. LÄS MER