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Voigt‐function modeling in Fourier analysis of size‐ and strain‐broadened X‐ray diffraction peaks
Author(s) -
Balzar D.,
Ledbetter H.
Publication year - 1993
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889892008987
Subject(s) - cauchy distribution , voigt profile , diffraction , fourier transform , fourier analysis , function (biology) , strain (injury) , gaussian , physics , fourier series , mathematics , distortion (music) , harmonic , mathematical analysis , optics , materials science , spectral line , quantum mechanics , evolutionary biology , biology , medicine , amplifier , optoelectronics , cmos
With the assumption that both size‐ and strain‐broadened profiles of the pure‐specimen function are described with a Voigt function, it is shown that the analysis of Fourier coefficients leads to the Warren–Averbach method of separation of size and strain contributions. The analysis of size coefficients shows that the `hook' effect occurs when the Cauchy content of the size‐broadened profile is underestimated. The ratio of volume‐weighted and surface‐weighted domain sizes can change from ~1.31, for the minimum allowed Cauchy content, to 2, when the size‐broadened profile is given solely by a Cauchy function. If the distortion Subscripts coefficient is approximated by a harmonic term, mean‐square strains decrease linearly with increasing the averaging distance. The local strain is finite only in the case of purely Gaussian strain broadening, because strains are then independent of averaging distance.