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Strain profiles in thin films: influence of a coherently diffracting substrate and thickness fluctuations
Author(s) -
Boulle A.,
Conchon F.,
Guinebretière R.
Publication year - 2009
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/s0021889808036406
Subject(s) - curvature , substrate (aquarium) , diffraction , strain (injury) , materials science , epitaxy , thin film , optics , displacement (psychology) , smoothness , crystallography , condensed matter physics , physics , geometry , chemistry , mathematical analysis , mathematics , composite material , nanotechnology , geology , layer (electronics) , medicine , psychology , oceanography , psychotherapist
A simple least‐squares fitting‐based method is described for the determination of strain profiles in epitaxial films using high‐resolution X‐ray diffraction. The method is model‐independent, i.e. it does not require any `guess' model for the shape of the strain profile. The shape of the vertical displacement profile is modelled using the versatile cubic B ‐spline functions, which puts smoothness and curvature constraints on the fitting procedure. The effect of a coherently diffracting substrate is taken into account as well as the effects of film thickness fluctuations. The model is applied to the determination of strain profiles in SmNiO 3 films epitaxically grown on SrTiO 3 (001) substrates. The shape of the retrieved strain profile is discussed in terms of oxygen vacancies.