Accurate determination of lattice parameters based on Niggli reduced cell theory by using digitized electron diffraction micrograph. (May 2017)

• Record Type: Journal Article
• Authors: Yang, Yi; Cai, Canying; Lin, Jianguo; Gong, Lunjun; Yang, Qibin
• Is Part Of: Micron. Volume 96(2017)
• Page Start: 9
• Page End: 15
• Publication Date: 2017-05
• Subjects: Niggli reduced cell -- Unit-cell determination -- Electron diffraction; Microscopy -- Periodicals; Electron Probe Microanalysis -- Periodicals; Microscopy -- Periodicals; Microscopie -- Périodiques; Microscopy; Periodicals; 502.82
• DOI: 10.1016/j.micron.2016.12.006
• Languages: English
• ISSNs: 0968-4328

Abstract

Highlights: Suitable to determinate lattice constants of a known or an unknown crystal. Measured angles directly on the electron micrographs instead of a double tilt holder. Used digitized micrographs and the least square method to optimize parameters. Enhanced the accuracy of lattice constant measurement obviously. Abstract: In this paper, we used Niggli reduced cell theory to determine lattice constants of a micro/nano crystal by using electron diffraction patterns. The Niggli reduced cell method enhanced the accuracy of lattice constant measurement obviously, because the lengths and the angles of lattice vectors of a primitive cell can be measured directly on the electron micrographs instead of a double tilt holder. With the aid of digitized algorithm and least square optimization by using three digitized micrographs, a valid reciprocal Niggli reduced cell number can be obtained. Thus a reciprocal and real Bravais lattices are acquired. The results of three examples, i.e., Mg4 Zn7, an unknown phase (Precipitate phase in nickel-base superalloy) and Ba4 Ti13 O30 showed that the maximum errors are 1.6% for lengths and are 0.3% for angles.