Mn dopant-enabled BiFeO3 with enhanced magnetic and photoelectric properties

In this study, BiFe1−XMnXO3 (BFMXO, x = 0, 0.03, 0.05, 0.07, 0.10, and 0.15) nanoparticles were synthesized using the sol-gel technique. The XRD patterns confirm that the BFMXO nanoparticles exhibit a rhombic structure with the addition of Mn dopant, while structural distortion occurred as the doping concentration increased. In particular, Mn doping effectively induced lattice shrinkage and enhanced the lattice strain. The SEM and TEM images showed increased uniformity and grain size reduction as Mn doping concentration increased. The XPS spectra show that the conversion of Fe2+ to Fe3+ leads to the increase of oxygen vacancy concentration. Further, the M−H loops show that the saturation magnetization and residual magnetization of all Mn-doped samples were successfully improved with the gradual transformation from antiferromagnetism to ferromagnetism. Therefore, BiFe0.93Mn0.07O3 reached a maximum Ms and Mr of approximately 0.956 and 0.054 emu/g, respectively. Further, BiFe0.93Mn0.07O3 exhibited 4–5 times higher photoconductivity than the pristine sample. First-principles calculations further accounted for the improved magnetic and electrical properties of BFMXO induced by the Mn dopant. This study demonstrates an effective method for controlling the structure and characteristics of BFO-based nanomaterials for multifunctional device applications.