Related Experiment Video
Updated: May 23, 2026
08:00
Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain
Published on: March 27, 2018
Persistence of surface domain structures for a bulk ferroelectric above TC
A Höfer1, M Fechner, K Duncker
1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany. anke.hoefer@physik.uni-halle.de
Physical Review Letters
|April 3, 2012
Summary
Surface ferroelectric domains in Barium Titanate (BaTiO3) persist above the bulk Curie temperature, maintaining patterns and contrast due to surface relaxation and residual tetragonal distortion.
Area of Science:
- Surface Science
- Condensed Matter Physics
- Materials Science
Background:
- Barium Titanate (BaTiO3) is a well-known ferroelectric material exhibiting a phase transition at its Curie temperature.
- Understanding the behavior of ferroelectric domains at surfaces is crucial for device applications and fundamental physics.
- The influence of temperature on surface ferroelectricity, especially above the bulk transition, remains an area of active research.
Purpose of the Study:
- To investigate the existence and characteristics of ferroelectric surface domains in BaTiO3 at temperatures exceeding the bulk Curie temperature.
- To correlate surface domain patterns with the bulk ferroelectric structure and understand the observed contrast mechanisms.
- To elucidate the role of surface relaxation and electronic structure in stabilizing surface domains above the Curie temperature.
Main Methods:
- Photoemission Electron Microscopy (PEEM) was employed to visualize surface domain structures on a prepared BaTiO3 surface.
- First-principles calculations were utilized to compare the work functions of different surface structures.
- Temperature-dependent domain analysis was performed across the bulk Curie transition.
Main Results:
- Surface ferroelectric domains in BaTiO3 were observed to persist at temperatures significantly above the bulk Curie temperature.
- The observed surface domain patterns mirrored the ferroelectric domain structure at room temperature (300 K).
- Contrast variations were noted for different domain polarizations, with inward polarized domains showing a sign change, while outward and in-plane polarized domains maintained their contrast.
Conclusions:
- The persistence of surface domains above the bulk Curie temperature is attributed to a remaining tetragonal distortion in the topmost unit cells.
- Ionic surface relaxation plays a critical role in stabilizing these surface domains.
- The observed domain contrast is linked to these residual surface distortions and their influence on work function.
Related Concept Videos
01:31Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
01:27Electrostatic Boundary Conditions in Dielectrics
When an electric field passes from one homogeneous medium to another, crossing the boundary between the two mediums imparts a discontinuity in the electric field. This results in electrostatic boundary conditions that depend on the type of mediums the field propagates through.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's permittivity.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's permittivity.
01:26Electric Field at the Surface of a Conductor
Consider a conductor in electrostatic equilibrium. The net electric field inside a conductor vanishes, and extra charges on the conductor reside on its outer surface, regardless of where they originate.
In the 19th century, Michael Faraday conducted the famous ice pail experiment to prove that the charges always reside on the surface of a conductor. The experimental set-up consists of a conducting uncharged container mounted on an insulating stand. The outer surface of the container is...
In the 19th century, Michael Faraday conducted the famous ice pail experiment to prove that the charges always reside on the surface of a conductor. The experimental set-up consists of a conducting uncharged container mounted on an insulating stand. The outer surface of the container is...
01:16Electrostatic Boundary Conditions
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
01:31Dielectric Polarization in a Capacitor
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...