Magnetism and electronic properties of BiFeO3 under lower pressure

Ab initio calculations show an antiferromagnetic-ferromagnetic phase transition around 9-10 GPa and a magnetic anomaly at 12 GPa in BiFeO₃. The magnetic phase transition also involves a structural and insulator-metal transition. The G-type AFM configuration under pressure leads to an increase of the y component and a decrease of the z component of the magnetization, which is caused by the splitting of the d_z² orbital from doubly degenerate e_g states. Our results agree with the recent experimental results.