Influence of humidity on domain evolution during local switching in single-domain strontium barium niobate

We have studied the influence of humidity on domain kinetics during local polarization reversal under the action of the field produced by a biased conductive tip in single-domain relaxor ferroelectric strontium barium niobate (Sr[Formula: see text]Ba[Formula: see text]Nb 2 O 6 ) crystals in the relative humidity (RH) range from 20 to 80%. The domain sizes increased with RH, and the domain wall became essentially rough. The effect was considered as a result of the nonhomogeneous distribution of the threshold fields caused by the nanoscale composition inhomogeneity. The formation of irregular nanodomain ensembles around the main domain at voltages above 200[Formula: see text]V for RH above 40% was attributed to partial spontaneous backswitching after tip withdrawal. The cone-shaped nonthrough domains with an aspect ratio of about 35 surrounded by dense nanodomain structures were revealed in the crystal bulk. The obtained dependence of the domain radius on the pulse duration was analyzed using the kinetic approach to the domain wall motion for current limited switching process with the water meniscus acting as a highly resistive electrode. The variable surface conductivity of the electrode has been attributed to the axially symmetric decrease of the water meniscus thickness with the distance from the tip. The used approach of 2D domain growth allowed us to fit the experimental data in an extremely wide range of pulse durations (five orders of magnitude).