ISSN:
1432-0630
Keywords:
78.70Bj
;
74.70Vy
;
61.70.-r
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract We report positron lifetime measurements in sintered superconducting YBa2Cu3O7−x and GdBa2Cu3O7−x oxides. It is shown that the thermal behaviour of the positron lifetime spectra strongly depends on the preparation of the ceramics. A lifetime of 190±3 ps is attributed to oxygen deficient regions. Two lifetimes of 251±7 ps and 225 ±5 ps are attributed to a cation vacancy presenting a temperature dependent atomic arrangement. The lifetime transition (251→225ps) occurs during decreases in temperature across the resistivity superconducting transition. This lifetime change indicates that the volume of the cation vacancy decreases in the superconducting state.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00618895
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