Search for dissertations about: "oxygen ordering"

Showing result 1 - 5 of 24 swedish dissertations containing the words oxygen ordering.

  2. 1. YBCO nanowires to study nanoscale ordering in High-Tc Superconductors

    Author : Riccardo Arpaia; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; nanoscale ordering; nanoSQUIDs; nanowires; High-Tc superconductors; ultrathin films; oxygen doping; nanowire-based single photon detectors;

    Abstract : We present the realization of YBa2Cu3O7-δ (YBCO) nanowires for both basic physics studies, which could help to elucidate the microscopic mechanisms of High critical Temperature Superconductors (HTS), and for novel applications.The first part of the thesis describes an improved nanopatterning procedure, based on e-beam lithography in combination with an amorphous carbon mask and a very gentle Ar+ ion etching. READ MORE

  4. 2. Atom-Probe Field-Ion Microscopy of Electronic Materials

    Author : Qiu-Hong Hu; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Au GaAs; ohmic contact; superconductors; oxygen ordering; AuGe GaAs; defects; Ag GaAs; Schottky contact; YBa2Cu3O6 delta; APFIM;

    Abstract : This thesis presents work in which atom-probe field-ion microscopy (APFIM) has been applied to two types of electronic materials. In the case of metal/GaAs contacts, the purpose was to characterise the microstructure of the contact interface, particularly the chemical composition variation across the interface. READ MORE

  5. 3. Beyond average crystal structures: understanding extended and local environments in proton-conducting Sc-substituted BaTiO3 perovskites

    Author : Nico Torino; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; proton conducting oxide; IR; thermogravimetry; perovskite; neutron scattering; Raman; Reverse Monte Carlo; ordering; BaTiO3;

    Abstract : Proton conducting ceramics are very promising for applications concerned with energy sourcing with cleaner, safer, more abundant and cheaper alternatives to fossil fuels. These materials are still in development and advances in the field depend on a better understanding of the role of defects, their identification and location in the host framework, and the assessment of their short- and long-range dynamics and kinetics. READ MORE

  6. 4. The Electrochemistry of LiNi0.5-xMn1.5+xO4-δ in Li-ion Batteries : Structure, Side-reactions and Cross-talk

    Author : Burak Aktekin; Kristina Edström; Daniel Brandell; Wolfgang Zipprich; Fernanda Lodi Marzano; Christian Masquelier; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; LNMO; High-voltage spinel; FEC; Cross-talk; Cation ordering; Oxygen deficiency; Anionic redox; Chemistry with specialization in Inorganic Chemistry; Kemi med inriktning mot oorganisk kemi;

    Abstract : The use of Li-ion batteries in portable electronic products is today widespread and on-going research is extensively dedicated to improve their performance and energy density for use in electric vehicles. The largest contribution to the overall cell weight comes from the positive electrode material, and improvements regarding this component thereby render a high potential for the development of these types of batteries. READ MORE

  7. 5. Density Functional Theory Applied to Materials for Spintronics

    Author : Diana Mihaela Iusan; Olle Eriksson; Biplab Sanyal; Hiroshi Katayama-Yoshida; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; spintronics; dilute magnetic semiconductors; density functional theory; exchange interactions; magnetic percolation; ordering temperature; disorder; electronic structure; Physics; Fysik; Materialvetenskap; Materials Science;

    Abstract : The properties of dilute magnetic semiconductors have been studied by combined ab initio, Monte Carlo, and experimental techniques. This class of materials could be very important for future spintronic devices, that offer enriched functionality by making use of both the spin and the charge of the electrons. READ MORE