  Recently several reports showing ultra-high electrostrain (> 1 %) have
appeared in Pb-free piezoceramics. However, there is lack of clarity on the
nature of the ultrahigh strain. Here, we demonsrate that the ultrahigh strain
is a consequence of bending of the disc. We show that the propensity for
bending arises from the difference in the response magnitude of the grains at
the positive and negative surfaces of the piezoceramic when the field is
applied.
