5.4 Piezoelectric Ceramics

Piezoelectric effect was discovered by Jacques and Pierre Curie in 1888. Direct piezoelectric effect is the ability of some materials to create an electric potential in response to applied mechanical stress. The applied stress changes the polarization density within the material's volume leading to the observed potential. As a requirement, only materials with non-centrosymmetric crystal structure can exhibit piezoelectric effect. Some of the commonly used/known piezoelectric materials are quartz (SiO₂), zinc oxide (ZnO), polyvinylidenefluoride (PVDF)  and lead zirconate titanate, (PZT or Pb(Zr,Ti)O₃). 

An oscillating applied stress on a piezoelectric material can give rise to the field which can be applied to an electrical load such as a bulb. Another example can be charging of your mobile or any other device in your backpack while you walk. You could not achieve the same while standing.

For a detailed discussion on the piezoelectric properties, materials, and applications, readers can refer to the bibliography provided in the beginning of the module.