Microstructural features and domain formation in (Ba,Sr) 2 TiSi 2 O 8 fresnoites

Date

2011

Authors

Wong, Chui Ling
Ferraris, Christiano
White, Timothy

Journal Title

Journal ISSN

Volume Title

Publisher

Academic Press

Abstract

The formation and co-existence of crystallographically modulated and non-modulated regions in (Ba,Sr)2TiSi2O8 fresnoites is reviewed, particularly the dependence on local composition. It is shown that perturbations of the average fresnoite structure, determined from appreciable single crystals, are in some cases better described as nanometric domain intergrowths where departures from ideal stoichiometry are characteristics of incommensuration, while modulation is absent from volumes that are less perturbed chemically. Evidence for this differentiation is obtained from selected area electron diffraction (SAED) patterns and high-resolution transmission electron microscopy (HRTEM) images. The domains are readily distinguished by their unique contrast in bright field electron micrographs. Fourier reconstructions of HRTEM images collected from areas with darker contrast show that modulation can change within relatively small volumes. Nearby areas with lighter contrast were found by SAED to be free of structural disorder and incommensurate reflections.

Description

Keywords

Keywords: (Ba,Sr)-fresnoite; Bright fields; Co-existence; Domain formation; Electron micrograph; Fourier reconstruction; Fresnoites; HRTEM images; Incommensuration; Inter-growths; Local compositions; Microstructural features; Nanometrics; Selected area electron dif (Ba,Sr)-fresnoite; Electron diffraction; Incommensuration; TEM

Citation

Source

Journal of Solid State Chemistry

Type

Journal article

Book Title

Entity type

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DOI

10.1016/j.jssc.2011.05.009

Restricted until

2037-12-31