Ferroelectric nanodomain properties in near-stoichiometric and congruent LiNbO3 crystals investigated by scanning force microscopy

The properties of ferroelectric nanodomains in LiNbO3 crystals were investigated using scanning force microscopy. In particular, we found differences in the domain shape, domain-wall sharpness, and lateral growth rate of domains in nearstoichiometric and congruent LiNbO3 crystals. In the near-stoichiometric NiNbO3 crystal, the domain dots are hexagonal and linear domains with smooth walls can be engineered parallel to one of the crystallographic Y-axes. The shape of the linear domains engineered at an angle to the crystallographic Y-axis changes when a small bias is applied during scanning, and various domain shapes are obtained after being stabilized by scanning. However, in the congruent LiNbO3 crystal, the domain dots are roughly circular and there is no change in the shape of the linear domains, which have rough domain walls. The lateral growth rate of domains in the congruent LiNbO3 Crystal is smaller than that in the near-stoichiometric LiNbO3 Crystal.