Publication
MS&T 2016
Conference paper

Patterning oxide nanopillars at the atomic scale by phase transformation

Abstract

Phase transformations in solids, usually altering the properties and behavior of materials, have attracted extensive interest in a variety of research fields ranging from materials science, information storage, to geological science. The ability to precisely control phase transformations of a material with high spatial precision represents a key step towards accurately tailoring material properties, yet still is extremely challenging due to the low spatial accuracy of controlling the energy injection into a material. Recent advances in aberration-corrected scanning transmission electron microscope (STEM) allow accurately manipulating a focused sub-Ångström electron beam to scan the samples with atomic resolution, which, if used for stimulating phase transformations in the irradiated materials, paves a way for the precise control of phase transformations at the atomic scale. Here we have used SrNbO3.4 single crystals which were prepared by the floating zone melting technique and steer a focused electron beam irradiating the ion-Thinned SrNbO3.4 TEM foils. We show a successful precise control of phase transformations in SrNbO3.4 at the atomic scale. The SrNbO3.4 phase with a layered perovskite structure, in which slabs of vertex-sharing NbO6 octahedra are interrupted by planes containing excess O atoms, is transformed into the perovskite SrNbO3 phase by electron irradiation. The excess O atoms are squeezed out and the neighboring slabs of vertex-sharing NbO6 octahedra are zipped together. The region of phase transformations can be dedicatedly designed with atomic spatial precision by a careful navigation of the STEM electron beam. The precise control of phase transformations should be very useful for materials design and processing, as well as the fabrication of advanced nanodevices.

Date

Publication

MS&T 2016

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