We report in this work on the variation of the optical bandgap and structural properties of epitaxial Bi 2 FeCrO 6 lms grown by pulsed laser deposition on SrTiO 3 (001) substrates. It is shown that the bandgap can be tuned by varying the laser repetition rate during deposition which has a strong impact on the Fe/Cr order inside the Bi 2 FeCrO 6 double perovskite structure. Ab initio band structure calculations unambiguously show that the presence of antisite defects lead to an increase of the gap with about 0.25 eV with respect to the one calculated in the ideal structure. It is also shown that with increasing Fe/Cr disorder the saturation magnetization is strongly reduced along with the dierence between the Fe and Cr valences. These results suggest that the bandgap of Bi 2 FeCrO 6 can eectively be engineered by modulating the deposition conditions, thus paving the way for applications such as photovoltaic conversion, memory writing and direct CMOS integration.

Ferroelectric materials are interesting candidates for future photovoltaic applications due to their potential to overcome the fundamental limits of conventional single bandgap semiconductor-based solar cells. Although a more efficient charge separation and above bandgap photovoltages are advantageous in these materials, tailoring their photovoltaic response using ferroelectric functionalities remains puzzling. Here we address this issue by reporting a clear hysteretic character of the photovoltaic effect as a function of electric field and its dependence on the poling history. Furthermore, we obtain insight into light induced nonequilibrium charge carrier dynamics in Bi2FeCrO6 films involving not only charge generation, but also recombination processes. At the ferroelectric remanence, light is able to electrically depolarize the films with remanent and transient effects as evidenced by electrical and piezoresponse force microscopy (PFM) measurements. The hysteretic nature of the photovoltaic response and its nonlinear character at larger light intensities can be used to optimize the photovoltaic performance of future ferroelectric-based solar cells.