Effect of samarium doping on the properties of solid-state synthesized multiferroic bismuth ferrite

Problems in the synthesis of phase-pure BiFeO3, a multiferroic material, are well known and presence of other phases often leads to inferior properties. Work reported here was carried out to obtain pure phase BiFeO3 via a solid-state-reaction method in both pure and Sm-doped form. X-ray diffraction (XRD) of the calcined undoped samples showed that maximum amount of pure BiFeO3 phase was obtained at a calcination temperature of 825 °C while a deviation in calcination temperature led to the increased amount of secondary phases such as Bi25FeO40. On the other hand, XRD patterns of Sm doped calcined samples of composition Bi0.9Sm0.1FeO3 revealed that secondary phases do not appear on calcination at and above 800 °C for 1 h in air. Vibrating sample magnetometry (VSM) measurements showed that Bi0.9Sm0.1FeO3 samples possess higher room temperature remnant magnetization than undoped samples. Temperature dependent measurements suggested antiferromagnetic behavior of Sm doped samples with Neèl temperature of ∼ 370 °C. Ferroelectric measurements showed that Sm doping improves the polarization but enhances the leakage current.