[citation needed] Electrostriction causes these materials to change their shape under the application of an electric field.
Electrostriction is a property of all dielectric materials,[2] and is caused by displacement of ions in the crystal lattice upon being exposed to an external electric field.
This displacement will accumulate throughout the bulk material and result in an overall strain (elongation) in the direction of the field.
The thickness will be reduced in the orthogonal directions characterized by Poisson's ratio.
[citation needed] The resulting strain (ratio of deformation to the original dimension) is proportional to the square of the polarization.
)[2] The electrostrictive tensor satisfies[1]: 666 The related piezoelectric effect occurs only in a particular class of dielectrics.