Search for dissertations about: "MgB2 superconductor"

Showing result 1 - 5 of 7 swedish dissertations containing the words MgB2 superconductor.

  2. 1. Magnesium Diboride (MgB2) and Ca-doped YBa2Cu3O7-? : Thin Films and Devices. Fabrication and Characterization

    Author : Anayesu Malisa; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ca-doped YBa2Cu3O7-?; MgB2; bicrystal; superconductor; nanobridge; thin film; Josephson effect; Josephson junction;

    Abstract : Magnesium diboride (MgB2) is a superconductor with an exceptionally high transition temperature, Tc, of 39 K. This work describes deposition of high quality and superconducting films of MgB2 for electronic applications. Experiments on Ca-doped YBa2Cu3O7-? films and fabrication of bicrystal Josephson junctions are also described. READ MORE

  4. 2. Superconducting THz mixers based on MgB2 film

    Author : Stella Bevilacqua; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bolometers; IF bandwidth.; superconductors; MgB2; THz Detectors; mixers;

    Abstract : Superconducting NbN hot electron bolometer (HEB) mixers are widely used in terahertz radio astronomy. Such mixers have superior performance compared to SIS and Schottky diode mixers at frequency above 1THz. However, their drawback is a limited IF bandwidth. READ MORE

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

    Author : Evgenii Novoselov; Chalmers tekniska högskola; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 4. Study of MgB2 and YBa2Cu3O7-x Microbolometers for THz Sensing Applications

    Author : Stella Bevilacqua; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; THz Detectors; bolometers; IF bandwidth; YBa2< sub>Cu3< sub>O7-x< sub>; Terahertz frequency; HEB; MgB2< sub>; noise; superconductors;

    Abstract : In this thesis, two novel THz detectors based on magnesium diboride (MgB2)and yttrium barium copper oxide (YBa2Cu3O7-x) are presented. In particular,MgB2 superconductor is used for the investigation of hot-electron bolometer(HEB) mixers, while YBa2Cu3O7-x is explored in microbolometers for room-temperaturecoherent and incoherent detection. READ MORE

  7. 5. Density Functional Theory in Computational Materials Science

    Author : Jorge Mario Osorio Guillén; Rajeev Ahuja; Börje Johansson; Bruce N. Harmon; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; Density Functional Theory; High Pressure; Phase Transitions; Elastic Properties; Lithium Batteries; Dilute Magnetic Semiconductors; Fysik; Physics; Fysik;

    Abstract : The present thesis is concerned to the application of first-principles self-consistent total-energy calculations within the density functional theory on different topics in materials science. Crystallographic phase-transitions under high-pressure has been study for TiO2, FeI2, Fe3O4, Ti, the heavy alkali metals Cs and Rb, and C3N4. READ MORE