Answer to Question #102639 in Molecular Physics | Thermodynamics for BIVEK SAH

Question

What are ferroelectric materials? Explain with the example of BaTiO3. How are
they different from piezoelectric materials?

Answer 1

Ferroelectric materials - these are materials in the crystal lattices of which polarization spontaneously occurs in certain temperature ranges, even if the electric field does not act on the substance.

As the temperature decreases in barium titanium crystals, a whole series of strictly defined phase transitions occurs due to the reorientation of the cubic (paraelectric) phase with the space group Pm3m to the tetragonal polar (ferroelectric) phase with the space group P4mm, then the transition to the orthorhombic polar phase with the space group Amm2 and , ultimately, to the rhombohedral polar phase with the space group R3m.

The main difference from piezoelectrics is that in the latter, which are dielectrics, the polarization effect occurs upon mechanical action.