Effect of doping on the morphology and multiferroic properties of BiFeO3nanorods

Abstract

In this study we report the synthesis of BiFeO₃ nanorods using a sonochemical technique. The nanorods had a diameter of 20–50 nm, a length of 100–500 nm and exhibit aspect ratios in the range of 5–10. However, after doping, the TEM images of Bi_0.9Ba_0.1Fe_0.9Mn_0.1O₃ and Bi_0.9Ca_0.1Fe_0.9Cr_0.1O₃ samples show that the aspect ratios of both the double doped samples have reduced considerably, while retaining the crystallinity of the particles. BiFeO₃ nanorods show a weak ferromagnetic order at room temperature, which is quite different from the linear M–H relationship reported for bulk BiFeO₃. The saturation magnetization of these BiFeO₃ nanostructures has been found to increase on doping with various metal ions (Ba²⁺, Ca²⁺, Mn²⁺, Cr³⁺), reaching a maximum value of 1.35 emu g⁻¹ for the Bi_0.9Ba_0.1Fe_0.9Mn_0.1O₃ nanostructures. However, saturation of electric polarization was observed only in case of the Bi_0.9Ca_0.1Fe_0.9Cr_0.1O₃ nanostructures.