Origin of suppressed polarization in BiFeO_3 films

摘要

We have studied the origin of suppressed remanent polarization in 4-variant BiFeO_3 by correlating microscopic observations of ferroelectric/ferroelastic domain structures and ferroelectric measurements of (001) epitaxial BiFeO_3 thin films with 2- and 4-ferroelastic domain variants. Piezoelectric force microscopy revealed that domain wall pinning was the cause of the reduced polarization observed in 4-variant BiFeO3. Using repetitive switching, the unswitched domains were completely switched and the remanent polarization reached a value comparable to 2-variant BiFeO_3. These results demonstrate that control of ferroelastic domains in rhombohedral systems is necessary in order to obtain high performance and reliable ferroelectric and magnetoelectric devices.