In:
Modern Physics Letters B, World Scientific Pub Co Pte Ltd, Vol. 08, No. 25 ( 1994-10-30), p. 1577-1585
Abstract:
In this paper, we present the positron lifetime data in high T c cuprate perovskite YBa 2 Cu 3− x Al x O y (x=0−0.4) systems. A significant Al substitution dependence of the positron lifetime parameters was observed, and the local electron density n e and defect concentration C d were also calculated as a function of Al substitution x. The results show that at low doping concentration, x≤0.15, both n e and C d exhibit a large change and then reach a limit value of saturation or a peak value above x=0.15 which corresponds just right to the known structural transition from orthorhombic to tetragonal phase. Here, the decrease in n e can be interpreted by weak electronic localization in Cu-O chains. The effect of n e on superconductivity and the mechanisms of positron annihilation were also discussed.
Type of Medium:
Online Resource
ISSN:
0217-9849
,
1793-6640
DOI:
10.1142/S0217984994001539
Language:
English
Publisher:
World Scientific Pub Co Pte Ltd
Publication Date:
1994
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