Use of Neutron Diffraction in Determining Strains in High-Temperature Superconducting Composites

1989 ◽  
Vol 166 ◽  
Author(s):  
D. S. Kupperman ◽  
J. P. Singh ◽  
S. Majumdar ◽  
J. Faber
Keyword(s):  
Neutron Diffraction ◽  
Barium Copper Oxide ◽  
General Purpose ◽  
Barium Copper ◽  
Yttrium Barium ◽  
Relationship Of ◽  
Oxide Composites ◽  
The Relationship ◽  
Pulsed Neutron ◽  
Pulsed Neutron Source

ABSTRACTThe Argonne Intense Pulsed Neutron Source and General Purpose Powder Diffractometer have been used to study high Tc metal oxide composites composed of yttrium barium copper oxide and silver. Neutron diffraction techniques were applied to composites with 15, 20 and 30% silver content by volume. We have observed that after hot pressing, the 30% Ag specimens contained both orthorhombic high Tc and tetragonal, non-superconducting phases near the center of the specimens but only tetragonal near the surface. The relationship of shifts in Bragg peaks to strains of the constituents is discussed.

X-ray and neutron diffraction of yttrium–barium–copper–oxide: Modeling diffraction intensity variations produced by surface leaching

1999 ◽  
Vol 14 (7) ◽  
pp. 2773-2777
Author(s):  
Seth A. Watkins ◽  
F. Hadley Cocks
Keyword(s):  
Neutron Diffraction ◽  
Barium Copper Oxide ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Barium Copper ◽  
Yttrium Barium ◽  
Normal Current ◽  
Diffraction Effects

High normal current fluences have long been reported to produce major changes in the x-ray diffraction pattern of YBa2Cu3O7−x (YBCO). These x-ray diffraction effects have now been shown to result from the removal of barium from the YBCO near-surface lattice together with the formation of a thin barium oxide overlayer. Neutron diffraction reveals that the bulk crystallographic structure remains unaltered by charge fluences of more than 40 million C/cm2, and Auger electron spectroscopy confirms the presence of surface barium enrichment.

Pulsed Microwave Processing of High-TC Superconducting Films

1992 ◽  
Vol 269 ◽  
Author(s):  
R. B. James ◽  
R. A. Alvarez ◽  
A. K. Stamper ◽  
X. J. Bao ◽  
T. E. Schlesinger ◽  
...  
Keyword(s):  
Phase Transition ◽  
Barium Copper Oxide ◽  
Precursor Film ◽  
Silicon Substrates ◽  
Molten Layer ◽  
Time Resolved ◽  
Barium Copper ◽  
In Situ Experiments ◽  
Yttrium Barium

ABSTRACTWe have used 2.0-μsec microwave pulses at a frequency of 2.856 GHz to rapidly heat thin amorphous yttrium-barium-copper-oxide (YBCO) films deposited onto silicon substrates. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 pulses in a traveling wave geometry. X-ray diffractometry studies show that an amorphous-to-crystalline phase transition occurs for incident pulse powers exceeding about 6 MW, in which case the amorphous YBCO layer is converted to Y2BaCuO5. Microscopy of the irradiated film reveals that the phase transition is brought about by melting of the YBCO precursor film and crystallization of the molten layer upon solidification. Time-resolved in situ experiments of the microwave reflectivity (R) and transmissivity (T) show that there is an abrupt change in R for microwave pulse powers exceeding the melt threshold, so that measurements of R and T can be used to monitor the onset of surface melting.

scholarly journals Flux Penetration Effects in High-Tc SQUIDs

1989 ◽  
Vol 42 (4) ◽  
pp. 401
Author(s):  
GJ SIoggett ◽  
lK Harvey ◽  
L Wieczorek ◽  
RE Binks ◽  
R Driver
Keyword(s):  
Magnetic Field ◽  
Copper Oxide ◽  
Direct Measurement ◽  
Barium Copper Oxide ◽  
Break Junction ◽  
Flux Penetration ◽  
High Tc ◽  
Bulk Ybco ◽  
Barium Copper ◽  
Yttrium Barium

Two experiments pertaining to the effects of intergranular flux penetration in high-Tc yttrium-barium-copper oxide (YBCO) SQUIDs are described. The first is a direct measurement of the flux noise of bulk YBCO exposed to the earth's magnetic field, and the second involves the fabrication and testing of break junction d.c. SQUIDs. Implications of a number of undesirable effects seen in these experiments are discussed.

ChemInform Abstract: NMR and NQR Studies in High-Tc Oxides: Yttrium Barium Copper Oxide, YBa2Cu3Oy (y = 6.0-6.91)

ChemInform ◽  
1990 ◽  
Vol 21 (3) ◽  
Author(s):  
H. YASUOKA ◽  
T. SHIMIZU ◽  
T. IMAI ◽  
S. SASAKI ◽  
Y. UEDA ◽  
...  
Keyword(s):  
Yttrium Barium Copper Oxide ◽  
Copper Oxide ◽  
Barium Copper Oxide ◽  
High Tc ◽  
Barium Copper ◽  
Yttrium Barium

Metal ion substitution chemistry in the yttrium barium copper oxide system as a probe of the superexchange pathway

1988 ◽  
Vol 110 (20) ◽  
pp. 6716-6720 ◽  
Author(s):  
Ruth. Jones ◽  
Peter P. Edwards ◽  
Martin R. Harrison ◽  
Thitinant. Thanyasiri ◽  
Ekkehard. Sinn
Keyword(s):  
Yttrium Barium Copper Oxide ◽  
Copper Oxide ◽  
Metal Ion ◽  
Barium Copper Oxide ◽  
Oxide System ◽  
Barium Copper ◽  
Substitution Chemistry ◽  
Ion Substitution ◽  
Yttrium Barium
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