Advanced Solid State Physics

(Axel Boer) #1

like the Curie-Weiss law:


χ=

1

T−TC

(255)

The fact that susceptibility and dielectric constant are related, causes the peak in the dielectric diagram
with aT^1 -decay. The peak in the diagram smears out because of impurities.


In such materials, domains with the same polarization direction are created. If higher electric fields
are applied, the ferroelectric domains get smaller. Some domains will point in one direction and some
in the other direction. This is done to minimize the electric energy, that’s the same what happens in
a ferromagnet. If a ferroelectric material is cooled down, the polarized domains will get very small
but macroscopically there will be no polarization. But if the material is cooled down in a strong
electric field, the domains will be pushed all in one direction, so the material will have a macroscopic
polarization.

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