Low voltage performance of epitaxial BiFeO3 films on Si substrates through lanthanum substitution

We have probed the role of La substitution on the ferroelectric properties of epitaxial BiFe O3 films on SrTi O3 -templated Si. This provides a mechanism to engineer the rhombohedral distortion in the crystal and, thus, control domain structure and switching. With a 10% La substitution, the (Bi0.9 La0.1) Fe O3 film showed well-saturated ferroelectric hysteresis loops with a remanent polarization of 45 μC cm2, a converse piezoelectric coefficient d33 of 45 pmV, and a dielectric constant of 140. Over this range of La substitution, the coercive field systematically decreases such that a coercive voltage of 1 V can been obtained in a 100 nm thick film. These results show promise for the ultimate implementation of this lead-free multiferroic operating at voltages in the range of 2-3 V. © 2008 American Institute of Physics.