Real-time observation of ferroelectric domains in NaNO 2 by nematic liquid crystal method

Ferroelectric domain structures in sodium nitrite crystal were studied by a nematic liquid crystal method. Under zero electric field, domain walls are parallel to (100) planes, but if an electric field is applied, domain walls parallel to (101) or (101) planes becomes stable. Domain switching under electric field is mainly accomplished by kink movement along the domain walls. Observation on domain patterns near the transition temperature was made using a high temperature nematic liquid crystal, and domains on cleaved surfaces which are parallel to the spontaneous polarization were also observed.