Both BiFeO3 (BFO) and Bi0.95Sm0.05Fe0.94Mn0.06O3 (BSFMO) nanoparticles were synthesized by the sonochemical technique. Microstructure and multiferroic properties of both BFO and BSFMO samples as a function of synthesis temperature were investigated. For BSFMO ceramic, pure perovskite phase was observed without any trace of conventional impurity ones; while a secondary phase (Bi2Fe4O9) are clearly observed in the XRD pattern of BFO ceramics. The TEM plots directly verify the formation of nano-sized ceramic powders for the both BFO and BSFMO systems. For each calcination temperature, the MS amounts of BSFMO nanoparticles are significantly higher than pristine ceramic. With decreasing temperature from 600 to 550 °C, the HC increases from 421 to 505 Oe and 297–418 Oe for BFO and BSFMO, respectively. From 550 to 400 °C, the HC diminishes for both pristine (~ 56%) and doped ceramics (~ 39%) due to the effect of nanocrystallites size smaller than magnetic exchange length. In addition, Sm and Mn co-doped sample shows an improved ferroelectric loop with lower leakage current. Generally, it was found that multiferroic (ferromagnetic and ferroelectric) properties of BSFMO ceramics were higher than BFO samples
