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Configuration and local elastic interaction of ferroelectric domains and misfit dislocation in PbTiO 3 /SrTiO 3 epitaxial thin films

Kiguchi, Takanori and Aoyagi, Kenta and Ehara, Yoshitaka and Funakubo, Hiroshi and Yamada, Tomoaki and NoritakaUsami, and Konno, Toyohiko J (2011) Configuration and local elastic interaction of ferroelectric domains and misfit dislocation in PbTiO 3 /SrTiO 3 epitaxial thin films. Science and Technology of Advanced Materials, 12 (3). 034413.

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Official URL: http://stacks.iop.org/1468-6996/12/i=3/a=034413

Abstract

We have studied the strain field around the 90° domains and misfit dislocations in PbTiO 3 /SrTiO 3 (001) epitaxial thin films, at the nanoscale, using the geometric phase analysis (GPA) combined with high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field––scanning transmission electron microscopy (HAADF-STEM). The films typically contain a combination of a/c- mixed domains and misfit dislocations. The PbTiO 3 layer was composed from the two types of the a -domain (90° domain): a typical a/c -mixed domain configuration where a -domains are 20–30 nm wide and nano sized domains with a width of about 3 nm. In the latter case, the nano sized a -domain does not contact the film/substrate interface; it remains far from the interface and stems from the misfit dislocation. Strain maps obtained from the GPA of HRTEM images show the elastic interaction between the a -domain and the dislocations. The normal strain field and lattice rotation match each other between them. Strain maps reveal that the a -domain nucleation takes place at the misfit dislocation. The lattice rotation around the misfit dislocation triggers the nucleation of the a -domain; the normal strains around the misfit dislocation relax the residual strain in a -domain; then, the a -domain growth takes place, accompanying the introduction of the additional dislocation perpendicular to the misfit dislocation and the dissociation of the dislocations into two pairs of partial dislocations with an APB, which is the bottom boundary of the a -domain. The novel mechanism of the nucleation and growth of 90° domain in PbTiO 3 /SrTiO 3 epitaxial system has been proposed based on above the results.

Item Type:Article
ID Code:11277
Deposited By:Prof. Alexey Ivanov
Deposited On:01 Nov 2011 23:30
Last Modified:02 Nov 2011 00:47

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