Electrical control of multiferroic orderings in mixed-phase BiFeO₃ films.

Recent advances in thin-fi lm engineering leads to a new type of mixed-phase system in BiFeO 3 (BFO) epitaxial fi lms driven by substrate strain. [ 1 ] Single-phase multiferroic BFO had attracted great interests due to its robust ferroelectric and antiferromagnetic orderings at room temperatures. [ 2–11 ] Under a strong compressive strain ( > 4%), the stable crystal structure of BFO transformed from the rhombohedral-like monoclinics (R) to tetragonal-like monoclinics (T), [ 12 , 13 ] and with suitable strain relaxation through thickness, the coexistence of R-BFO and T-BFO phases can be obtained in the same fi lm. [ 1 , 14–18 ]