In our calculations, the commensurable and collinear G-type antiferromagnetic structure rather than the real spiral spin structure was used. Similar method was also used in Co doped BiFeO3. It is clear that SB705498 GGA + U are necessary for the correct prediction of the equilibrium volume and structural parameters. This is consistent with a conclusion drawn from the first-principles calculations on BiFeO3 . Table 2 compared calculated structural parameters of pure BiFeO3 and BiFe0.83Co0.17O3 systems in hexagonal cell.