Determination of the effective coercive field of ferroelectrics by piezoresponse force microscopy

The effective coercive field Ec for ferroelectric domain reversal is usually determined in a capacitor-like geometry by increasing an applied electric field until poling occurs. Here we present a different method based on local poling with the tip of a scanning force microscope and analyzing the dependence of the domain size on the poling parameters. This method for determining Ec is of importance because for many samples the standard technique fails, either because they are too small in size, or because they are slightly conductive. Results obtained on lithium niobate crystals of different composition conform to literature values.