In-plane polarization contribution to the vertical piezoresponse force microscopy signal mediated by the cantilever “buckling”

Rigorous experimental/theoretical approach to measure and to minimize in-plane piezoresponse contribution to the vertical piezoresponse force microscopy (PFM) signal is presented. In-plane piezoresponse mediated by the cantilever “buckling” is shown to affect apparent vertical PFM signal being of the same order of magnitude as a true out-of-plane piezoresponse. Decoupling of these two contributions based on simple mathematical procedure is demonstrated. Row PFM data are analyzed as a function of the laser beam focus position on the cantilever allowing suppression of “buckling” contribution and, hence, measurement of only out-of-plane piezoresponse component. This approach can be used for the accurate recovery of the piezoresponse displacement vector, what is of paramount importance for the reconstruction of the domain structures and quantitative characterization of the polarization distribution and local piezoelectric properties in ferroelectric materials.