Material Scinece has played a vital role in the development of society. Characterization
is an important step in the development of different types of new materials. This experiment is
aimed to expose the young students to Dielectric and Curie Temperature Measurement
techinque for Ferroelectric Ceramics.
Dielectric or electrical insulating materials are understood as the materials in which
electrostatic fileds can persist for a long time. These materials offer a very high resisitance to
the passage of electric current under the action of the applied direct-current voltage and
therefore sharply differ in their basic electrical properties from conductive materials. Layers of
such substances are commonly inserted into capacitors to improve their performance, and the
term dielectric refers specifically to this application.
The use of a dielectric in a capacitor presents several advantages. The simplest of these
is that the conducting plates can be placed very close to one another without risk of contact.
Also, if subjected to a very high electric field, any substance will ionize and become a
conductor. Dielectrics are more resistant to ionization than air, so a capacitor containing a
dielectric can be subjected to a higher voltage. Also, dielectrics increase the capacitance of the
capacitor. An electric field polarizes the molecules of the dielectric (Figure-1), producing
concentrations of charge on its surfaces that create an electric field opposed (antiparallel) to
that of the capacitor. Thus, a given amount of charge produces a weaker field between the
plates than it would without the dielectric, which reduces the electric potential. Considered in
reverse, this argument means that, with a dielectric, a given electric potential causes the
capacitor to accumulate a larger charge.