Ferroelectricity's a spontaneous electric polarization of a material that can be reversed by the application of an external electric field. The term's used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was already known when ferroelectricity was discovered in 1920 in Rochelle salt by Valasek. Thus, the prefix ferro, meaning iron, was used to describe the property despite the fact that most ferroelectric materials don't have iron in their… (More on Ferroelectricity)