Lithium Niobite (LiNbO3) is an optically transparent, piezo responsive material used, for example, in piezo sensors or in mobile phones. We tested a LiNbO3 sample (PFM03, obtained from TipsNano, Estonia) with CoreAFM. The sample has a regular domain structure with 10-µm period. The spontaneous polarization has the opposite direction in the neighboring domains.
To measure the piezoresponse during imaging, a 7.5 V AC voltage was applied to the cantilever while raster scanning the tip over the sample. In response to the applied voltage, the sample periodically expands and shrinks, either in phase with or in counter phase to the excitation frequency. Despite a small measured RMS roughness of 0.3 nm, the domains could not be recognized in the topography. The domains could however be readily identified in the out of plane piezoresponse.