Improper ferroelectrics as high‐efficiency energy conversion materials

Abstract

An improper ferroelectric is a certain type of ferroelectrics whose primary order parameter is not polarization but another physical quantity such as magnetization. In contrast to a conventional proper ferroelectrics as represented by Pb(Zr,Ti)O3 and BaTiO3, the improper ferroelectrics has been inconceivable for practical applications thus far. Herein, we illustrate the great potential of improper ferroelectrics for efficient conversion of temperature fluctuation to electric energy, as demonstrated with (Ca0.84Sr0.16)8[AlO2]12(MoO4)2 (CSAM‐16). The present study has experimentally proven that CSAM‐16 achieves an excellent electrothermal coupling factor and high electric field sensitivity for pyroelectric energy conversion that approach a practical level for application to self‐powered autonomous electronic devices for rapidly spreading wireless sensor networks. The present results provide a novel approach to developing innovative pyroelectric energy harvesting devices using improper ferroelectrics.