Relaxor ferroelectrics are

ferroelectric Ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoelectric and pyroelectric, with the ad ...

materials that exhibit high

electrostriction Electrostriction (cf. magnetostriction) is a property of all electrical non-conductors, or dielectrics, that causes them to change their shape under the application of an electric field. Explanation Electrostriction is a property of all dielectr ...

. , although they have been studied for over fifty years, the mechanism for this effect is still not completely understood, and is the subject of continuing research. Examples of relaxor ferroelectrics include: *

lead magnesium niobate Lead magnesium niobate is a relaxor ferroelectric. It has been used to make piezoelectric microcantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat v ...

(PMN) * lead magnesium niobate-lead titanate (PMN-PT) *

lead lanthanum zirconate titanate Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, l ...

(PLZT) * lead scandium niobate (PSN) *Barium Titanium-Bismuth Zinc Niobium Tantalum (BT-BZNT) *Barium Titanium-Barium Strontium Titanium (BT-BST)

Applications

Relaxor Ferroelectric materials find application in high efficiency energy storage and conversion as they have high dielectric constants, orders-of-magnitude higher than those of conventional ferroelectric materials. Like conventional ferroelectrics, Relaxor Ferroelectrics show permanent dipole moment in domains. However, these domains are on the nano-length scale, unlike conventional ferroelectrics domains that are generally on the micro-length scale, and take less energy to align. Consequently, Relaxor Ferrolelectrics have very high specific capacitance and have thus generated interest in the fields of energy storage. Furthermore, due to their slim hysteresis curve with high saturated polarization and low remnant polarization, Relaxor ferroelectrics have high discharge energy density and high discharge rates. BT-BZNT Multilayer Energy Storage Ceramic Capacitors (MLESCC) were experimentally determined to have very high efficiency(>80%) and stable thermal properties over a wide temperature range.

References

Electric and magnetic fields in matter Ferroelectric materials Electrical phenomena {{electromagnetism-stub