Effect of Ti substitution in place of Fe on crystal symmetries and magnetic properties of Bi0.850La0.150FeO3

Lanthanum (La) modified BFO crystallize to an impurity free crystal structure and enhance the multiferroic properties in BFO. The Bi0.850La0.150FeO3 is found to be optimized composition to have very good multiferroic properties. It is also reported that the Ti4+ substitution significantly reduces the leakage current in BFO. Moreover, the Ti4+ substitution is more effective than that of magnetic cations to increase the magnetization. Hence, Bi0.850La0.150Fe1-xTixO3 (x = 0.000, 0.025, 0.050, 0.100) polycrystalline samples were synthesized by the tartaric acid modified sol gel method and the effect of non-magnetic Ti substitution at the Fe-site of Bi0.850La0.150FeO3 on crystal structure and magnetic properties has been studied. The Rietveld refinements of X-ray diffraction patterns indicate the structural transition from rhombohedral (R3c) to orthorhombic (Pbnm) with the increase in the substitution concentration. A gradual shift in the frequency of Fe-O stretching modes toward higher frequency in the FTIR spectra indicates a composition-driven structural transition. Magnetic properties of Bi0.850La0.150Fe1-xTixO3 polycrystalline samples were measured at room temperature with the applied field range of ±7 T. A significant increase in the magnetization with Ti substitution is observed from the magnetic hysteresis loops. The highest magnetic moment was observed for 2.5% Ti substitution at the Fe-site in Bi0.850La0.150FeO3.