A comparison of HREM and weak beam transmission electron microscopy for the quantitative measurement of the thickness of ferroelectric domain walls

Abstract

In this paper we present two methods for the quantitative measurement of the thickness of ferroelectric domain walls, one using high-resolution electron microscopy (HREM) and the other weak beam transmission electron microscopy (WBTEM). These techniques can be used to determine the thickness of domain walls at room temperature as well as close to the ferroelectric to paraelectric phase transition. The first method allows a direct visualization of the lattice distortion across the domain wall, by measuring the continuous deviation of a set of planes with respect to the undistorted lattice. The second method consists in a quantitative analysis of the thickness fringes that appear on weak beam images of inclined domain walls. By fitting simulated fringe profiles to experimental ones, we can extract the thickness of the domain walls in a quantitative way. These two complementary techniques lead to a complete characterization of the thickness of ferroelectric domain walls over a wide range of specimen thicknesses at different magnifications. As an example we apply these methods to ferroelectric domain walls in PbTiO 3 . The domain wall thickness at room temperature is found to be 1.5 ± 0.3 nm using HREM (in very thin samples =10 nm) and 2.1 ± 0.7 nm using WBTEM (in samples thicker than 30 nm).Keywords high-resolution electron microscopy, weak beam imaging, ferroelectric domain walls, PbTiC^, image simulation, quantitative electron microscopy

Ab initiostudy of ferroelectric domain walls inPbTiO3

“…• domain wall in PbTiO 3 was further confirmed by Foeth et al 11 From their HRTEM images they obtained a width of 15±3Å at room temperature, and from the analysis of the thickness fringes of weak-beam transmission electron microscopy (WBTEM) they found a value of 21±7Å. In contrast, Floquet et al…”

“…Most studies so far have used high-resolution transmission electron microscopy (HRTEM) to obtain direct images of the domain walls. [7][8][9][10][11] In a detailed study of 90…”

Impact of the tip radius on the lateral resolution in piezoresponse force microscopy

“…Detecting the Raman modes with a confocal defect-luminescence microscope, an influence of the domain wall in LiNbO 3 further than 1 µm into the surrounding material was observed [10]. On the other hand, high-resolution transmission electron microscopy yielded a domain wall width in PbTiO 3 of <2.8 nm [11] and with scanning nonlinear dielectric microscopy, a width of only 0.5 nm in ultra-thin PbZrTiO 3 films was determined [12].…”

Configuration and local elastic interaction of ferroelectric domains and misfit dislocation in PbTiO3/SrTiO3epitaxial thin films

“…Among these approaches, GPA is advantageous for the spatial resolution and robustness of image quality. GPA has been applied to various materials such as metals, semiconductors and oxides [12][13][14][15][16][17][18][19][20].…”

“…• domain structures of the bulk PbTiO 3 and BaTiO 3 crystals have been examined in earlier studies [12][13][14], but only for the simple 90…”