Lm. Eng et al., NONDESTRUCTIVE IMAGING AND CHARACTERIZATION OF FERROELECTRIC DOMAINS IN PERIODICALLY POLED CRYSTALS, Journal of applied physics, 83(11), 1998, pp. 5973-5977
We report the nondestructive investigation and visualization of period
ically poled domains in ferroelectric potassium titanyl phosphate (KTP
) crystals using polarization sensitive scanning force microscopy (SFM
). Applying an alternating voltage technique to SFM allows ferroelectr
ic domain wall resolution beyond 100 nm. Image contrast between KTP an
d Rb doped KTP, i.e., rubidium titanyl phosphate (RTP) regions arises
from the differential piezoelectric response. We find the polarization
vectors in both KTP and RTP to be aligned parallel to the negative z
axes as deduced (a) when comparing our data with a ferroelectric refer
ence sample, i.e., tri-glycine sulfate (b) from comparison of nanoscal
e hysteresis loops recorded on KTP and RTP, and (c) from direct domain
switching in KTP applying very high electric fields between tip and c
ounter electrode. The latter experiments show that nanoscale ferroelec
tric domains in KTP switch from the negative to the positive z-axes al
ignment for electric fields stronger than 750 V/cm. Nevertheless, spon
taneous backswitching is observed after a couple of minutes. (C) 1998
American Institute of Physics. [S0021-8979(98)06511-6].