Pyroelectric and electrocaloric materials

Both the pyroelectric and electrocaloric effects originate from the crosscoupling between polarization and temperature in insulating dielectrics. Although both effects have been studied for many decades for various applications and large pyroelectric effect has been observed in many polar-dielectrics, it is only very recently that a large electrocaloric effect (ECE) was obtained in ferroelectric ceramic thin films and polymers, which revives the interest in the ECE. This review will summarize typical properties of pyroelectric and electrocaloric materials, present figures of merit for both phenomena, and examine the relationship between the pyroelectric effect and ECE. Moreover, we will also present theoretical works, experimental results, and material modifications to achieve large responses in electrocaloric materials.