STRUCTURAL AND MAGNETIC PHASE TRANSITIONS OF BiFeO3 INDUCED BY PRESSURE

First-principles calculations on BiFeO3 under low-pressure region show that the rhombohedral-monoclinic and rhombohedralorthorhombic phase transitions can be found around the critical pressure value, similar to 9 GPa. We suggest that the structure involve the combination of these three phases and change to the pure orthorhombic phase gradually as pressure is beyond the critical value. Moreover, it is a first-order structural phase transition, accompanied with antiferromagnetic - ferromagnetic transition.