About ferroelectricity
Ferroelectricity:
The dipoles in certain solids are spontaneously aligned, in a particular direction, even in the absence of electric field. Such substances are called ferroelectric substance and the phenomenon is called ferroelectricity. However, the direction of polarisation in these substances can be changed on applying electricity. Examples of ferroelectric solids are (BaTiO³), Rochelle salt (sodium potassium tartarate), potassium dihydrogen phosphate) (KH²PO⁴) etc.