Effect of doping on the morphology and multiferroic properties of BiFeO3 nanorods

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 Bi0.9Ba0.1Fe0.9Mn0.1O3 and Bi0.9Ca0.1Fe0.9Cr0.1O3 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 Bi0.9Ba0.1Fe0.9Mn0.1O3 nanostructures. However, saturation of electric polarization was observed only in case of the Bi0.9Ca0.1Fe0.9Cr0.1O3 nanostructures.