Effect of Pb Doping on Multiphase Coexistence and Magneto-electric Properties of Bismuth Ferrite

摘要

The Bi_((1-x))Pb_xFeO_3 (x=0, 0.1, 0.2, and 0.3) powders have been synthesized via a sol-gel method employing natural iron sands as Fe~(3+) ion source of starting material. Multiphase of bismuth ferrite such as BiFeO_3, Bi_(25)FeO_(40), and Bi_2 Fe_4O_9 were observed in the synthesized powders. The Pb doping decreases the phase formation of the BiFeO_3 while increases the phases formation of other bismuth ferrite phases. A structural transformation from rhombohedral to pseudocubic system of the BiFeO_3 was observed with the substitution of Pb~(2+). The powders exhibit BiFeO_3 phase having crystal size of 27-83 nm. The Pb doping has strengthened both the magnetic and electric properties of the samples. The grain size of the powders decreased with the substitution of Pb-doping. The sample with x=0.1 shows the maximum magnetic moment at room temperature. The dielectric properties of the samples enhance with increasing Pb contents at room temperature. The magnetoresistance of the samples was estimated by the changes in the resistivity under the external magnetic field.