Polarization Screening Effect on Local Polarization Switching Mechanism and Hysteresis Loop Measurements in Piezoresponse Force Microscopy

Piezoresponse Force Spectroscopy (PFS) has emerged as a powerful tool for probing polarization dynamics on the nanoscale. Application of a dc bias to a nanoscale probe in contact with a ferroelectric surface results in the nucleation and growth of a ferroelectric domain below the probe apex. The latter affects local electromechanical response detected by the probe. Resulting hysteresis loop contains information on local ferroelectric switching. The self-consistent analysis of the PFS data requires (a) deriving the thermodynamic parameters of domain nucleation and (b) establishing the relationships between domain parameters and PFM signal. Here, we analyze the effect of screening at the domain wall on local polarization reversal mechanism. It is shown that the screening control both the domain nucleation activation energy and hysteresis loop saturation rate.