Berlin 2008 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 5: Scanning and diffraction methods
DF 5.1: Hauptvortrag
Montag, 25. Februar 2008, 14:30–15:10, EB 407
Behaviour of Ferroelectrics Influenced by Nanoscale Morphology — •john martin gregg1, alina schilling1, liwu chang1, mark mcmillen1, mohamed saad1, robert bowman1, gustau catalan2, james scott2, and finlay morrison3 — 1School of Maths and Physics, Queen’s University Belfast, Belfast, U. K. — 2Department of Earth Sciences, Cambridge University, Cambridge, UK — 3Department of Chemistry, University of St Andrews, St Andrews, Scotland, U. K.
This talk describes attempts made to simplify the study of nanoscale ferroelectrics by minimizing the influence of defects, microstructure and to some extent boundary-related strain effects by using a Focused Ion Beam Microscope (FIB) to cut thin film sheets and nanowires directly from bulk single crystal ferroelectrics.
Low field permittivity characteristics of FIB-cut thin film BaTiO3 sheets have been investigated, and it has been shown that bulk-like permittivity response persists even in films as thin as ∼ 70nm. This result contradicts decades of previous work done on conventionally grown thin film ferroelectric heterostructures.
In addition the domain characteristics of single crystal thin sheets and nanowires have been characterised as a function of scale and of morphology using Scanning Transmission Electron Microscopy. The domain periodicities and polar orientations observed show a dramatic sensitivity to both size and shape. It has been shown that nanoscale morphology can be used to control polar orientation along the lengths of single nanowires.