Nanoscale domain structures in 0.91Pb(Zn1/3Nb2/3)O3-0.09PbTiO3 (91PZN-9PT) single crystals studied by piezoresponse forcemicroscopy

High-resolution domain studies have been performed in 91PZN-9PT single crystals by piezoresponse force microscopy. Nanometer- and micron-sized strip-shaped 180o and parallel 90o domains were observed in the rhombohedral (R) and tetragonal (T) phases. Domain patterns with the typical sizes 5-200nm were observed on the (001)(cub) surface of unpoled sample. The existence of nanodomains in the sample is tentatively attributed to the relaxor nature of PZN-PT where small polar clusters may form under zero-field cooling conditions. The domain observation confirms the structure of the morphotropic 91PZN-9PT crystals, which is composed of both the R and T (or monoclinic) orientations states. The outstanding piezoelectric properties may result from the cooperative response of the microscale/nanoscale domain structure.