5.3.12 Applications of Ferroelectrics

In addition to BaTiO₃, extensively studied ferroelectric materials have been PbTiO₃, Pb(Zr,Ti)O₃ , Bi₄Ti₃ O₁₂ and SrBi₂Ta₂O₉. While the first two show large polarization and a reasonably high T_c (above 400°C), the latter two do not contain lead and have higher Curie transition temperatures.

Although many applications of ferroelectrics are for their piezoelectric properties (see section 5.4), ferroelectrics can be used for applications like non-volatile data storage below their T_c. Above T_c where their dielectric constant increases linearly with temperature, they can be used for camera flashes.

5.3.12.1 Nonvolatile Memories

Since ferroelectric materials show a hysteresis loop and remnant polarization ±P_R at zero field, these two polarization states can be used as ‘0’ and ‘1’ states of binary data storage in memory devices. The advantages are that data will be stored when power is lost during operation leading to non-volatile data storage. Other advantages are that ferroelectric switching is a very fast phenomenon and hence memories can operate very fast. Many of these materials tend to be radiation resistant and hence can be used in space applications.

5.3.12.2 Camera Flashes

In this application, the battery charges the ferroelectric capacitor first. Then, once fully charged, the ferroelectric is connected to the bulb and causes it to flash.