Synthesis and ferroelectric properties of epitaxial BiFeO 3 thin films grown by sputtering

We have grown epitaxial BiFe O3 thin films with smooth surfaces on (001), (101), and (111) SrTi O3 substrates using sputtering. Four-circle x-ray diffraction and cross-sectional transmission electron microscopy show that the BiFe O3 thin films have rhombohedral symmetry although small monoclinic distortions have not been ruled out. Stripe ferroelectric domains oriented perpendicular to the substrate miscut direction and free of impurity phase are observed in BiFe O3 on high miscut (4°) (001) SrTi O3, which attributes to a relatively high value of remanent polarization (∼71 μC cm2). Films grown on low miscut (0.8°) SrTi O3 have a small amount of impure phase α- Fe2 O3 which contributes to lower the polarization values (∼63 μC cm2). The BiFe O3 films grown on (101) and (111) SrTi O3 exhibited remanent polarizations of 86 and 98 μC cm2, respectively. © 2006 American Institute of Physics.