Electric-field-induced evolution of domain shapes in polarization reversal of BiFeO3 (111) capacitors

Relying on an external electric field, the shape of propagating domains evolves in polarization switching of ferroelectric BiFeO3 (111) capacitors. With an increasing negative switching bias, it is shown that the domain pattern during ferroelectric domain growth evolves from a circular shape to a dendrite-like shape. Electrical current measurements for different poling states reveal that holes are easily injected through the BiFeO3/SrRuO3 interface under a negative voltage bias. It is found that holes injected by large negative-switching-pulse fields facilitate domain nucleation in BiFeO3 (111) films and thereby, the promoted domain nucleation drives the shape of switched domains to be dendrite-like.