The electric and optical properties of a solid whose chemical composition is Na 1/2Bi1/2TiO3 (NBT) is modified using application of electric field alone. Interestingly the shifts in atomic positions that are induced due to applied electric field is irreversible!

Ref: J. Appl. Phys. 117, 244106 (2015); http://dx.doi.org/10.1063/1.4923222