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Chemistry

2005

Faculty Publications, Chemistry

Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

Phases Found At Grain Boundary Of Yba2cu3o7-D 50 Nm Films On Srtio3 By Enhanced Anomalous Scattering At O:K, Cu:L2,3 And Ba:M4,5 Edges, Juana Acrivos Sep 2005

Phases Found At Grain Boundary Of Yba2cu3o7-D 50 Nm Films On Srtio3 By Enhanced Anomalous Scattering At O:K, Cu:L2,3 And Ba:M4,5 Edges, Juana Acrivos

Faculty Publications, Chemistry

A new phase is detected within 100micrometers of 24 DEG ab grain boundary (GB) in YBa2Cu3O7-d 50 nm films on SrTiO3 by enhanced (001) anomalous scattering. Site identification and temperature dependence is interpreted using crystallographic weights to distinguish enhanced scattering from total electron yield and fluorescence spectra. The c-axis, c0 indicates that only ortho-I phase is present far from GB, both ortho-I and II phases are present near GB. The phase c0 is constant versus temperature across the transition to superconductivity.

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Enhanced Anomalous Scattering By Superconducting Nanofilms Vs T At O:K, Cu:L2,3 , Ba:M4,5 Edges, Juana Acrivos Sep 2005

Enhanced Anomalous Scattering By Superconducting Nanofilms Vs T At O:K, Cu:L2,3 , Ba:M4,5 Edges, Juana Acrivos

Faculty Publications, Chemistry

Enhanced (001) anomalous scattering by YBa2Cu3O7-δ 50 nm films on SrTiO3 substrates with and without a grain boundary versus temperature is interpreted using crystallographic weights to distinguish it from total electron yield and fluorescence spectra. The power of diffraction enhancement is to ascertain the film oxygen composition from the changes in the c-axis, c0 as the film surface is scanned across the grain boundary, and to determine that c0 is constantversus temperature across the superconducting phase transition.

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Investigation Of The Anisotropy Of Dissipation Processes In Single Crystal Of Yba2cu3o7-D System, J Chigvinadze, A. Lashvili, Juana Acrivos, T. Machaidze, T. Wolf Aug 2005

Investigation Of The Anisotropy Of Dissipation Processes In Single Crystal Of Yba2cu3o7-D System, J Chigvinadze, A. Lashvili, Juana Acrivos, T. Machaidze, T. Wolf

Faculty Publications, Chemistry

By means of contactless mechanical method of the measurement of energy losses in superconductors, the anisotropy of dissipation processes has been studied in single crystal high-temperature layered superconductors of Yba2Cu3O7-d system, being in mixed state. The observed anisotropy of energy losses indicates the possibility of the existence of the symmetry of order parameter of dx2-y2 type in these single crystals.

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Electro-Magnetic-Optical Properties Of Yba2cu3o7 Crystal And 50 Nm Films On Sto-Bc 24 Deg Gb, Juana Acrivos, H. Sahibudeen, L. Nguyen, M. Navacerrada, J Kortight, P. Nachimuthu Mar 2005

Electro-Magnetic-Optical Properties Of Yba2cu3o7 Crystal And 50 Nm Films On Sto-Bc 24 Deg Gb, Juana Acrivos, H. Sahibudeen, L. Nguyen, M. Navacerrada, J Kortight, P. Nachimuthu

Faculty Publications, Chemistry

Comparison of Is/I0 with TEY/I0, F/I0 and A, at the Cu L2,3 and Ba M4,5 edges indicates that YBa2Cu3O7 (YBCO) 50 nm films scatters the circular components of linearly polarized light in a different way. The YBCO, Ba L2,3 XAS shows indication of Faraday rotation near Tc. Hilbert analysis of data was done.

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Yba2cu3o7 Electro-Magneto-Optic Effects In Ba L2,3 X-Ray Absorption Near Tc, Juana Vivó Acrivos Jan 2005

Yba2cu3o7 Electro-Magneto-Optic Effects In Ba L2,3 X-Ray Absorption Near Tc, Juana Vivó Acrivos

Faculty Publications, Chemistry

The onset of electro magneto-optic effects, observed at the Ba L2,3 edges synchrotron X-ray absorption by a YBa2Cu3O7 single crystal, 10 K above the transition temperature to superconductivity, Tc ~ 92 K is used to identify the role played by the Ba donor layer in the transition to superconductivity in the CuO2 layers. Negative permeability leads to Faraday rotation of the transmitted beam below T = 112 to 56 K for the 22 μm thick single crystal (c-axis orientation of 8π/18 relative to εX-rays) and sharp changes in the density of empty final states lead to zero transmitted radiation in …

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Characterization Of The Electronic Excited-State Energetics And Solution Structure Of Lanthanide(Iii) Complexes With The Polypyridine Ligand 6,6'-Bis[Bis(2-Pyridylmethyl)Aminomethyl]-2,2'-Bipyridine, Gilles Muller, P. Gawryszewska, J. Sokolnicki, A. Dossing, J. P. Riehl, J. Legendziewicz Jan 2005

Characterization Of The Electronic Excited-State Energetics And Solution Structure Of Lanthanide(Iii) Complexes With The Polypyridine Ligand 6,6'-Bis[Bis(2-Pyridylmethyl)Aminomethyl]-2,2'-Bipyridine, Gilles Muller, P. Gawryszewska, J. Sokolnicki, A. Dossing, J. P. Riehl, J. Legendziewicz

Faculty Publications, Chemistry

Absorption, emission, and excitation spectra for solid-state and solution of Tb(III), Dy(III), and Gd(III) complexes with the polypyridine ligand 6,6‘-bis[bis(2-pyridylmethyl)-aminomethyl]-2,2‘-bipyridine (C36H34N8) are presented. Measurements of excited-state lifetimes and quantum yields in various solvents at room temperature and 77 K are also reported and used to characterize the excited-state energetics of this system. Special attention is given to the characterization of metal-to-ligand energy transfer efficiency and mechanisms. The measurement of circularly polarized luminescence (CPL) from the solution of the Dy(III) complex following circularly polarized excitation confirms the chiral structure of the complexes under study. No CPL is present in the luminescence …

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Comparative Study Of Structural Properties Of Yba2cu3o7 Thin Films On Srtio3 Single Crystal And Bicrystal Substrates By X- Ray Diffraction, M. Navacerrada, A. Mehta, H. Sahibudeen, Juana Acrivos Jan 2005

Comparative Study Of Structural Properties Of Yba2cu3o7 Thin Films On Srtio3 Single Crystal And Bicrystal Substrates By X- Ray Diffraction, M. Navacerrada, A. Mehta, H. Sahibudeen, Juana Acrivos

Faculty Publications, Chemistry

We present a comparative study in terms of structural properties deduced from X - ray diffraction diagrams between YBa2Cu3O7 (YBCO) thin films fabricated on SrTiO3 (STO) single crystal substrates and bicrystallines substrates with a symmetrical tilt angle of 24 degrees. Periodic Lattice Distortions (PLD) have been observed around different Bragg peaks in YBCO thin films deposited on STO bicrystals while only diffraction peaks have been measured in the diagrams corresponding to the YBCO thin films deposited on STO single crystal substrates. Only in regions situated a 3.5 mm at both sides of the grain boundary the PDL have been investigated. …

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