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Vacancies and Precipitates in Al–1.9 at% Cu Studied by Positrons
Author(s) -
Gläser U. H.,
Dlubek G.,
Krause R.
Publication year - 1991
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221630203
Subject(s) - positron , trapping , annihilation , positron annihilation , atomic physics , materials science , positronium , condensed matter physics , physics , nuclear physics , electron , ecology , biology
Abstract Experimental and theoretical investigations of positron trapping by disk shaped Guinier‐Preston zones as appearing in AlCu alloys are performed. Using positron lifetime and angular correlation S ‐parameter measurements the decomposition phenomena are studied in an Al–1.9 at% Cu alloy. The energy and the wave function of a positron within a cylindrical shaped trap is calculated using Ritz's variational principle. Although a weak localization of the positrons by multilayer Guinier‐Preston zones (GP zones) is to be expected from theory, the experimental spectra are dominated by positron annihilation in vacancies surrounded by Cu atoms. Above 200 °C positron trapping by semicoherent and incoherent precipitates is found.