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The influence of twinning in YBa/sub 2/Cu/sub 3/O/sub 7/ on positron annihilation parameters

Conference ·
OSTI ID:6565663

Positron annihilation spectroscopy has been applied to the study of the high temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7/minus/delta/; delta = 0.1. Both positron lifetime and Doppler line shape measurements have been completed. Initial experiments revealed a correlation between a decrease in the line shape parameter S and the superconducting transition temperatures (T/sub c/) of YBa/sub 2/Cu/sub 3/O/sub 7/ (T/sub c/ = 90 K) and YBa/sub 2/Cu/sub 3/O/sub 6.6/ (T/sub c/ = 46 K). In YBa/sub 2/Cu/sub 3/O/sub 7/ the positron lifetime was also found to decrease at and below T/sub c/. More recent work revealed a different temperature dependence for the Doppler line shape parameter S. The physical origin of these samples dependent differences and their relevance to superconductivity is under investigation. Preliminary work suggest the differences be related to crystal twinning. 11 refs., 2 figs., 3 tabs.

Research Organization:
Brookhaven National Lab., Upton, NY (USA)
DOE Contract Number:
AC02-76CH00016
OSTI ID:
6565663
Report Number(s):
BNL-41323; CONF-8808122-14; ON: DE89004518
Country of Publication:
United States
Language:
English