Coupling of the remanent polarisation in thin film oxide ferroelectrics with nematic liquid crystals

The technique of domain visualisation, revealed by a film of nematic liquid crystal (NLC) on a ferroelectric crystal substrate, is demonstrated for th e first time to be applicable to thin films of lead zirconate-lead titanate (PZT) ferroelectric ceramics. PZT film thicknesses <1 mu m were deposited on indium tin oxide coated glass substrates. Commercially available NLC mat erials with positive dielectric anisotropy were employed. The electro-optic properties of devices incorporating the ferroelectric ceramic and NLC are reported. The poled PZT grains induce a local Freedericksz transition in th e NLC and it is proposed that the ferroelectric-NLC interaction is primaril y due to the depolarisation field due to the ferroelectric remanent polaris ation.