Sökning: "High-Tc superconductor"

Visar resultat 11 - 15 av 24 avhandlingar innehållade orden High-Tc superconductor.

1. 11. Reshaping the phase diagram of YBa2Cu3O7-δ through strain in ultrathin films and nanowires

   Författare :Eric Wahlberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; phase-slip; strange metal; High-Tc superconductors; thin-films; underdoped; nanowires; YBCO; charge density wave;

   Sammanfattning : This thesis aims at adding important pieces to the puzzle of understanding the physics of the High critical Temperature Superconductor (HTS) cuprates, where despite over 30 years of intense research many open questions remain. The HTS cuprates are characterized by an incredibly complex phase diagram with multiple intertwined local orders, such as charge density waves (CDW). LÄS MER

3. 12. Studies of systems related to high-Tc superconductors by electron microscopy and X-ray powder diffraction

   Författare :Ingrid Bryntse; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : New cuprate systems related to high temperature superconductors have been investigated and are reviewed. The synthesized samples have been studied mainly by transmission electron microscopy, energy-dispersive spectrometry and X-ray powder diffraction, in order to determine composition and structure of the formed phases. LÄS MER

4. 13. Characteristic properties of two-dimensional superconductors close to the phase transition in zero magnetic field

   Författare :Kateryna Medvedyeva; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; superconductor; two dimensions; phase transition; vortex; currentvoltage characteristics; complex conductivity; scaling; critical exponents; XY-type models; dynamics; Physics; Fysik; fysik; Physics;

   Sammanfattning : The main focus of this thesis lies on the critical properties of twodimensional (2D) superconductors in zero magnetic field. Simulations based on variants of the 2D XY model are shown to give characteristic features close to the phase transition which agree qualitatively with experimental data. LÄS MER

5. 14. MgB2 hot-electron bolometer mixers for sub-mm wave astronomy

   Författare :Evgenii Novoselov; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; hot-electron bolometer; gain bandwidth; noise bandwidth; thin film; electron-phonon interaction; noise temperature; THz detector; conversion gain; mixer; magnesium diboride; superconductor;

   Sammanfattning : Spectroscopy and photometry in the terahertz (THz) range of remote space objects allows for a study of their chemical composition, because this range covers rotational lines from simple molecules and electron transition lines from atoms and ions. Due to high spectral resolution, THz heterodyne receivers al- low for studying dynamical properties of space objects manifested in doppler-shifted emission lines. LÄS MER

7. 15. Theory of Electron Transport in Superconducting Heterostructures

   Författare :Magnus Hurd; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis deals theoretically with electron transport in superconducting heterostructures. Depending on the system I use different theoretical approaches. The thesis contains an introduction followed by four research papers (Papers I-IV). The introduction gives the background of the work in Papers I-IV. LÄS MER