Theoretical study of ferroelectric nanoparticles using phase reconstructed electron microscopy

Abstract

Ferroelectric nanostructures are important for a variety of applications in electronic and electro-optical devices, including nonvolatile memories and thin-film capacitors. These applications involve stability and switching of polarization using external stimuli, such as electric fields. We present a theoretical model describing how the shape of a nanoparticle affects its polarization in the absence of screening charges, and quantify the electron-optical phase shift for detecting ferroelectric signals with phase-sensitive techniques in a transmission electron microscope. We provide an example phase shift computation for a uniformly polarized prolate ellipsoid with varying aspect ratio in the absence of screening charges.

Temperature Dependence of Dielectric Constant and Loss Tangent in Methyl Ammonium Aluminium Alum

“…It is well known that ferroelectric materials find potential applications in technology due to their peculiar properties. They are used in memory devices as like infrared detectors, optical modulators, large capacitors etc 1 . Methyl ammonium aluminum alum (MASD), (CH 3 NH 3 )Al(SO 4 ).12H 2 O is ferroelectric below 177 K. In high temperature phase the CH 3 NH 3 groups are found to be symmetrically oriented so that they are indistinguishable from each other 2 .…”