Abstract
Structural and superconducting properties of high temperature superconductors were studied by experiment and computer simulation. Oxygen ordering in CuO{sub x} basal plane of the high temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} were studied by Monte Carlo computer simulation based on the so-called ASYNNNI model (Asymmetric Next Nearest Neighbor Interaction model), and formation of specific domains of the two orthorhombic ordered oxygen phases, Ortho-I and Ortho-II, as function of oxygen stoichiometry x was related to T{sub c}(x), via a Minimal Model. A similar relation has been established between temporal variation of T{sub c}(t) and structural oxygen ordering during relaxation following quench from high temperatures. By neutron diffraction on single crystalline YBa{sub 2}Cu{sub 3}O{sub 6.4}, presence of short range domains of Ortho-II type structure has been established, and degree of ordering has been found to scale with observed T{sub c} according to expectations from the established Minimal Model. From neutron diffraction on Pb{sub 2}Sr{sub 2}Re{sub 1-x}Cu{sub 3}O{sub 8} (RE=Y and Ho), transition from non-superconducting to superconducting samples with increasing Ca-stoichiometry was related to change in Cu bond valence in superconducting CuO{sub 2}-planes. X-ray diffraction with Euler four-circle technique and TEM were used to identify structural defects in epitaxial YBa{sub 2}Cu{sub 3}O{sub 6+x}
More>>
Citation Formats
Hessel Andersen, N.
Structural studies of ceramic superconductors; Strukturelle undersoegelser af keramiske superledere.
Denmark: N. p.,
1993.
Web.
Hessel Andersen, N.
Structural studies of ceramic superconductors; Strukturelle undersoegelser af keramiske superledere.
Denmark.
Hessel Andersen, N.
1993.
"Structural studies of ceramic superconductors; Strukturelle undersoegelser af keramiske superledere."
Denmark.
@misc{etde_10140978,
title = {Structural studies of ceramic superconductors; Strukturelle undersoegelser af keramiske superledere}
author = {Hessel Andersen, N}
abstractNote = {Structural and superconducting properties of high temperature superconductors were studied by experiment and computer simulation. Oxygen ordering in CuO{sub x} basal plane of the high temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} were studied by Monte Carlo computer simulation based on the so-called ASYNNNI model (Asymmetric Next Nearest Neighbor Interaction model), and formation of specific domains of the two orthorhombic ordered oxygen phases, Ortho-I and Ortho-II, as function of oxygen stoichiometry x was related to T{sub c}(x), via a Minimal Model. A similar relation has been established between temporal variation of T{sub c}(t) and structural oxygen ordering during relaxation following quench from high temperatures. By neutron diffraction on single crystalline YBa{sub 2}Cu{sub 3}O{sub 6.4}, presence of short range domains of Ortho-II type structure has been established, and degree of ordering has been found to scale with observed T{sub c} according to expectations from the established Minimal Model. From neutron diffraction on Pb{sub 2}Sr{sub 2}Re{sub 1-x}Cu{sub 3}O{sub 8} (RE=Y and Ho), transition from non-superconducting to superconducting samples with increasing Ca-stoichiometry was related to change in Cu bond valence in superconducting CuO{sub 2}-planes. X-ray diffraction with Euler four-circle technique and TEM were used to identify structural defects in epitaxial YBa{sub 2}Cu{sub 3}O{sub 6+x} thin films produced on MgO (1 0 0) and SrTiO{sub 3} (1 0 0) substrates by laser ablation. Results supply an explanation for the differences in observed critical current densities, and may be used for optimizing the film production process. A computer-controlled gasvolumetric and a gas-mixing flow system for sample preparation of high temperature superconductors, and studies of oxygen equilibrium pressure and bulk oxygen diffusion.}
place = {Denmark}
year = {1993}
month = {Dec}
}
title = {Structural studies of ceramic superconductors; Strukturelle undersoegelser af keramiske superledere}
author = {Hessel Andersen, N}
abstractNote = {Structural and superconducting properties of high temperature superconductors were studied by experiment and computer simulation. Oxygen ordering in CuO{sub x} basal plane of the high temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} were studied by Monte Carlo computer simulation based on the so-called ASYNNNI model (Asymmetric Next Nearest Neighbor Interaction model), and formation of specific domains of the two orthorhombic ordered oxygen phases, Ortho-I and Ortho-II, as function of oxygen stoichiometry x was related to T{sub c}(x), via a Minimal Model. A similar relation has been established between temporal variation of T{sub c}(t) and structural oxygen ordering during relaxation following quench from high temperatures. By neutron diffraction on single crystalline YBa{sub 2}Cu{sub 3}O{sub 6.4}, presence of short range domains of Ortho-II type structure has been established, and degree of ordering has been found to scale with observed T{sub c} according to expectations from the established Minimal Model. From neutron diffraction on Pb{sub 2}Sr{sub 2}Re{sub 1-x}Cu{sub 3}O{sub 8} (RE=Y and Ho), transition from non-superconducting to superconducting samples with increasing Ca-stoichiometry was related to change in Cu bond valence in superconducting CuO{sub 2}-planes. X-ray diffraction with Euler four-circle technique and TEM were used to identify structural defects in epitaxial YBa{sub 2}Cu{sub 3}O{sub 6+x} thin films produced on MgO (1 0 0) and SrTiO{sub 3} (1 0 0) substrates by laser ablation. Results supply an explanation for the differences in observed critical current densities, and may be used for optimizing the film production process. A computer-controlled gasvolumetric and a gas-mixing flow system for sample preparation of high temperature superconductors, and studies of oxygen equilibrium pressure and bulk oxygen diffusion.}
place = {Denmark}
year = {1993}
month = {Dec}
}