Ferroelectric domain structure of the BiFeO3 film grown on different substrates

Domain structure of BiFeO₃ (BFO) films grown on different substrates, with a conductive La_0.7Sr_0.3MnO₃ underlayer, has been experimentally studied. Two oppositely orientated polarizations, along the long body diagonal to the perovskite unit cell of BFO, are detected in the BFO films on the (0 0 1)-oriented NdGaO₃. Electric pulses applied in the 0 0 1] direction produce a polarization switching, resulting in the domain structure characterized by the 109° domain walls. Contrary to the BFO films on NdGaO₃, the BFO films on SrTiO₃ (0 0 1) exhibit a much complex domain structure. Both 71° and 109° domain walls are possible with a uniform polarization component pointing to the bottom electrode.