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A Model for the Calculation of Monovacancy and Divacancy Contributions to the Impurity Diffusion in Noble Metals
Author(s) -
Neumann G.
Publication year - 1987
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.2221440129
Subject(s) - diffusion , curvature , impurity , effective diffusion coefficient , activation energy , vacancy defect , arrhenius plot , thermodynamics , arrhenius equation , chemistry , condensed matter physics , materials science , physics , medicine , radiology , magnetic resonance imaging , geometry , mathematics , organic chemistry
On the basis of an earlier proposed model (Neumann and Hirschwald 1973, 1974) the impurity diffusion in noble metals is described by additionally taking into account the contribution of divacancies. The influence of the divacancy contribution on the effective diffusion energy and on the temperature dependence of the isotope effect is discussed. The divacancy contribution causes a curvature of the Arrhenius plot of the diffusion coefficient. For fast diffusing impurities the temperature behaviour of the correlation factor f leads to a distinct decrease of this curvature. A further consequence of the temperature behaviour of f for fast diffusers is that the low‐temperature value of Δ Q , the difference between the activation energies of impurity diffusion and self‐diffusion, represents an acceptable upper limit for the binding energy between impurity and vacancy.