Observation of ferroelectric domain boundaries in BaTiO3by transmission and reflection electron microscopy

1993 ◽  
Vol 140 (1) ◽  
pp. 203-210 ◽  
Author(s):  
F. Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Ferroelectric Domain ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy ◽  
Transmission And Reflection

Reflection electron microscopy of ferroelectric domains

1994 ◽  
Vol 52 ◽  
pp. 568-569
Author(s):  
Feng Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Crystal Surface ◽  
Dark Field ◽  
Ferroelectric Domain ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Crystal Surfaces ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy

The intersections of ferroelectric domain boundaries with crystal surfaces have been studied by optical microscopy. The method is widely used but usually of low resolution. Transmission electron microscopy (TEM) can provide high-resolution images but may not be appropriate for studying crystal surfaces. Scanning electron microscopy (SEM) has also been used to study the intersections of ferroelectric domain boundaries with the surfaces of ferroelectric crystals. However, the resolution is still low and is destructive if an etched crystal surface is used. Other alternatives have also been attempted to study ferroelectric domain boundaries on surfaces, such as scanning tunneling microscopy (STM), atomic force microscopy (AFM). But, no reports have been known so far.On the other hand, reflection electron microscopy (REM), as a branch of dark-field imaging technique dedicated for surface studies in TEM, has been developed to study crystal surfaces, surface reconstruction and surface defects with a resolution of about 10Å. It has been considered as a powerful technique to study surface defects and may be used to study the ferroelectric domain boundaries emerging on surfaces.

Contrasts of planar defects in reflection electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 1004-1005
Author(s):  
Feng Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Practical Importance ◽  
Theoretical Treatment ◽  
Crystal Surfaces ◽  
Planar Defects ◽  
Surface Steps ◽  
Surface Reconstructions ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy

Reflection electron microscopy (REM) has been used to study surface defects such as surface steps, dislocations emerging on crystal surfaces, and surface reconstructions. However, only a few REM studies have been reported about the planar defects emerging on surfaces. The interaction of planar defects with surfaces may be of considerable practical importance but so far there seems to be only one relatively simple theoretical treatment of the REM contrast and very little experimental evidence to support its predications. Recently, intersections of both 90° and 180° ferroelectric domain boundaries with BaTiO3 crystal surfaces have been investigated by Tsai and Cowley with REM.The REM observations of several planar defects, such as stacking faults and domain boundaries have been continued by the present authors. All REM observations are performed on a JEM-2000FX transmission electron microscope. The sample preparations may be seen somewhere else. In REM, the incident electron beam strikes the surface of a crystal with a small glancing angle.

REM Studies of Adsorption-Induced Phase Transitions and Faceting in the Si(111)-Au System

1998 ◽  
Vol 05 (03n04) ◽  
pp. 653-663 ◽  
Author(s):  
Koyu Aoki ◽  
Hiroki Minoda ◽  
Yasumasa Tanishiro ◽  
Katsumichi Yagi
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Surface Structure ◽  
Lower Side ◽  
Domain Boundaries ◽  
Adsorption Processes ◽  
Reflection Electron Microscopy ◽  
Step Down ◽  
Successive Phase

Initial stages of Au adsorption processes on Si(111)-(7 × 7) surfaces at ~780°C, a temperature range where the surface structure undergoes successive phase transitions [(7 × 7)–("1 × 1")–(5×2)–("1 × 1")], were observed in situ by reflection electron microscopy. All of the phase transitions are heterogeneous on the surface and start at surface atomic steps. During Au adsorption on Si(111)-(7 × 7), and subsequently on Si(111)-("1 × 1") surface with wide terraces, steps advance toward the step-down direction. At a Au coverage of ~0.3 ML, the 5 × 2 structure nucleates at step edges, and the nuclei expand both to the lower side terraces and to the higher side terraces. At this stage, an effect of current for heating the specimen was noted. From measurements of such movements of the steps and the domain boundaries, the density of Si atoms in the "1 × 1" phase is estimated to be 1.3–1.7 ML at a Au coverage of ~0.3 ML. Au adsorption on Si(111) surfaces with narrow terraces causes bunching of the steps. After nucleation of the 5 × 2 structure, the bunched [Formula: see text] steps become straight along the [Formula: see text] direction, and are transformed into the (335) facet planes at a Au coverage of 0.50 ML. It was found that the (335) facet planes are stabilized by adsorbed Au atoms. Destruction of the (335) facet is noted at a Au coverage of 0.73 ML.

Features of the ferroelectric domain structure in the multiferroic material YbMnO3

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 591-596
Author(s):  
Takumi Inoshita ◽  
Yasuhide Inoue ◽  
Yoichi Horibe ◽  
Yasumasa Koyama
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Domain Structure ◽  
Ferroelectric Domain ◽  
Multiferroic Material ◽  
Ferroelectric State ◽  
Hexagonal Axis ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries

ABSTRACTThe multiferroic material YbMnO3 has been reported to exhibit both ferroelectric and antiferromagnetic orders in the ground state. Of these two orders, the ferroelectric order is associated with the P63/mmc-to-P63cm structural transition, which occurs around 1270 K. The interesting feature of the ferroelectric state is that a cloverleaf domain structure with a pseudo-six-fold symmetry is observed in transmission electron microscopy images with the beam incidence parallel to the hexagonal axis. To understand the origin of the formation of the cloverleaf domain structure, we have examined the crystallographic features of the ferroelectric state in YbMnO3 by transmission electron microscopy. In this study, particularly, we adopted the experimental condition that electron beam incidences are perpendicular to the hexagonal axis. It was, as a result, found that there existed various ferroelectric domain structures including the cloverleaf domain structure under the present condition. The notable feature of domain structures found in this study is that each domain structure basically consists of six domains, whose domain boundaries are terminated at one point. Because this feature makes us reminiscent of a discommensurate structure in an incommensurate state, we took high-resolution electron micrographs of areas including domain boundaries. Their analysis indicated that a domain boundary could be identified as a discommensuration with a phase slip of π/3. It is thus understood that the cloverleaf domain structure should be one of domain morphologies for a discommensurate structure, which is related to the break of the translational symmetry.

Observation of ferroelectric domain boundaries in BaTiO3 with REM

1992 ◽  
Vol 50 (1) ◽  
pp. 360-361
Author(s):  
Feng Tsal
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Ferroelectric Material ◽  
Crystal Surfaces ◽  
Etching Technique ◽  
Surface Steps ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy ◽  
Etched Surface

The earlier work of transmission electron microscopy(TEM) on ferroelectric domains have been concentrated on the studies of domain configurations and contrast theory, Scanning electron microscopy(SEM) is also used to study ferroelectric material surfaces and has revealed various domain boundaries on the chemical-etched surface of BaTiO3. However, the method is destructive and largely dependent on the etching technique. Reflection electron microscopy (REM) has recently been developed to study crystal surfaces, especially the surface defects such as surface steps and emerging dislocations. This paper presents the observation of 90° domain boundaries in BaTiO3 single crystal with REM and concentrates on the contrast of 90° domain boundaries.

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