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The use of direct convolution products in profile and pattern fitting algorithms. II. Application of the algorithms
Author(s) -
Yau J. K.,
Howard S. A.
Publication year - 1989
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/s0021889888014499
Subject(s) - algorithm , crystallite , rietveld refinement , convolution (computer science) , annealing (glass) , materials science , mathematics , analytical chemistry (journal) , crystallography , mineralogy , computer science , chemistry , composite material , crystal structure , artificial intelligence , metallurgy , chromatography , artificial neural network
The use of the profile shape function based on the direct convolution product described in paper I [Howard & Snyder (1989). J. Appl. Cryst. 22 , 238–243] in profile and Rietveld pattern fitting algorithms has been investigated further. These algorithms aided in the fabrication of a better instrument‐profile standard and in determining the crystallite size and strain in a series of specimens. Analysis of an A1 specimen using a profile fitting algorithm yielded its strain and the strain recovery rate as a function of annealing time and temperature. The results from a modified Rietveld program showed the strain in La‐substituted SrTiO 3 specimens to be a function of the La content and the oxygen partial pressure in which the specimens were annealed. In all cases, the specimen's contributions to line broadening as a result of both small crystallite size and strain in this study were similar to the results obtained in paper I, i.e. they tended to be Lorentzian in nature.