Strain tunability of spontaneous polarization and enhanced ferroelectric properties in epitaxial (001) BiFeO3 thin films

We report the strain dependence of remanent polarization and coercive field of epitaxial (001)p BiFeO3 films. Our measurements reveal that the large spontanoues polarization of BiFeO3 is indeed intrinsic, the remanent polarization of (001)p BiFeO3 thin films has a strong strain dependence, even stronger than (001) PbTiO3 films, and the coercive field of BiFeO3 films is also tunable. In addition, the low coercive filed and the reduced leakage current in (001)p BiFeO3 membranes allows us to achieve a fatigue-free switching behavior to 1010 cycles. This experimental result strongly suggests that epitaxial (001)p BiFeO3 thin films are very promising materials for non-volatile memories and magnetoelectric devices.