A pair of electrical charges (+ and -) constitute a dipole. Polarity results from the uneven partial charge distribution. The polarity of a electrically charged system is measured in terms of the electric dipole moment, p which is the product of charge, q and the displacement vector, r. When a material exhibits spontaneous electric dipole moment, it has ferroelectric property. The polarity can be reversed by applying an electric field in these materials.

Ferroelectric materials are used in dynamic random access memories (DRAMS), non-volatile ferroelectric random access memories micro-armours and infrared sensors. Lead titanate (PbTiO3), lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), and lead magnesium niobate (PMN) are some of the ferroelectric ceramic materials.