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Posted: Oct 15, 2015
Patterning oxide nanopillars at the atomic scale by phase transformation
(Nanowerk News) Researchers at Tohoku University's Advanced Institute for Materials Research (AIMR) have carried out a collaborative study aimed at precisely controlling phase transformations with high spatial precision, which represents a significant step forward in realizing new functionalities in confined dimensions.
The team, led by Prof. Yuichi Ikuhara, applied the focused electron beam of a scanning transmission electron microscope (STEM) to irradiate SrNbO3.4 crystals, and demonstrated a precise control of a phase transformation from layered SrNbO3.4 to perovskite SrNbO3 at the atomic scale.
Phase transformations in crystalline materials are of primary fundamental interest and practical significance in a wide range of fields, including materials science, information storage and geological science. To date, it remains highly desirable to precisely tailor the phase transformations in a material due to their potential impact on macroscopic properties and thus many advanced applications.
Despite decades of efforts, precisely controlling phase transformations at the atomic scale still poses a significant challenge due to the intricacies of governing thermodynamic conditions with atomic precision. Recent technical advances in aberration-corrected STEM offer fertile new ground for probing samples by a focused sub-Angström electron beam, opening an avenue for precisely triggering phase transformations.
This work has demonstrated a successful control of a phase transformation from the layered SrNbO3.4 to the perovskite SrNbO3 with atomic precision by manipulating a focused sub-Angström electron beam to any selectable region.
Such a concept - of a precise control of phase transformations with an atomic spatial precision - should be, in principle, applicable not only to SrNbO3.4/SrNbO3 but also to other materials, finding applications in material processing and nanodevice fabrication.