The physical properties of BiFe_0.75Mn_0.125Ti_0.125O₃ and La doped BiFe_0.75Mn_0.125Ti_0.125O₃ were first investigated by first principles calculation.

Ti and Mn co-doping has improved the magnetic moment of 2×1×2$2\times 1\times 2$ BiFeO₃ (zero magnetic moment) to ∼3μ_B$\sim 3{\mu }_B$.

The band gap of TM is direct, while those of BiFeO₃ and La doped TM (La_yBi_1 − yFe_0.75Ti_0.125Mn_0.125O₃ (y=0.125,0.25$y=0.125,0.25$)) are indirect.

La doping into the B sites of BiFe_0.75Mn_0.125Ti_0.125O₃ makes it more potential application on photovoltaic.

BiFe_0.75Mn_0.125Ti_0.125O₃ is transparent in the hole studied energy range, while La_yBi_1 − yFe_0.75Ti_0.125Mn_0.125O₃ (y=0.125,0.25$y=0.125,0.25$) is nontransparent in the visible light region.