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Relations between Characteristics of Point Defects and Bulk Properties of Solids a Criticism of the Varotsos‐Alexopoulos Model
Author(s) -
Bekf D. L.,
Neumann G.,
Szabó I. A.
Publication year - 1989
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.2221550207
Subject(s) - thermodynamics , activation energy , physics , pure mathematics , chemistry , mathematics
Using the similarity of the effective potentials seen by ions in solids general relations between characteristics of point defects (i.e. the volume v i , the entropy s i and the energy Q i of formation, migration, and activation) and bulk properties of solids are derived. It is shown that the basic assumption of the Varotsos‐Alexopoulos‐model (VA‐model) is not necessarily valid. Using dimensional analysis the validity conditions of this model are expressed in a form of partial differential equation from which relations “derived” by Varotsos and Alexopoulos are obtained. Their relations are different from the here obtained results because the ratios of v i , s i , and Q i are proportional to expressions containing only bulk parameters of the solid, while in the relations obtained by us there are proportionality factors depending on i , i.e. these constants are different for the formation, migration, and activation (formation plus migration) processes. It is also shown that the basic assumption of the VA‐model is not valid for a harmonic solid. Experimental data for f.c.c. metals definitely confirm these results instead of those obtained by Varotsos and Alexopoulos.