Ferroelectric nanodomain Patterning in stoichiometric LiNbO3 crystal

Microscale to nanoscale ferroelectric domain engineering of a near-stoichiometric LiNbO3 crystal was investigated by using a scanning force microscope. The single crystal LiNbO3 (with 1% MgO doping) was grown by the double-crucible Czochralski method with automatic powder supply system. The electric field required to inverse the polarization direction of the domain was about one-ninth of the filed for a conventional congruent LiNbO3. The near-stoichiometric LiNbO3 crystal fixed on metal substrate was polished to a thickness of approximately 5 mum. Polarization directions of the domains were locally inverted by applying voltages with a conductive cantilever of the scanning force microscope. Furthermore, the domain structure was patterned in the LiNbO3 samples, where the domains were inverted by scanning with the cantilever on the sample while applying voltages.