Sol–gel synthesis and investigation of structural, electrical and magnetic properties of Pb doped La_0.1Bi_0.9FeO₃ multiferroics

A sol–gel based auto-combustion technique has been employed to synthesize polycrystalline La_0.1Bi_0.9−xPb_xFeO₃ (x = 0.0, 0.05, 0.10, 0.20, 0.30) ceramics. The samples have been characterized by X-ray diffraction, scanning electron microscopy, an LCR-meter and a vibrating sample magnetometer for their structural and morphological features, as well as electrical and magnetic properties, respectively. The structural analysis revealed that when Pb was doped at Bi-sites in La_0.1Bi_0.90FeO₃, the host retained the rhombohedrally distorted perovskite structure, attributed to the non centro-symmetric space group R3c. The surface morphological studies revealed that the grain size was increased and formed agglomerates at high concentrations of Pb contents. The dielectric parameters displayed conventional ferrite behavior depicting high values at low frequencies and decreasing with rise in frequencies, leading to constant values at still higher frequencies. The magnetic properties were changed non-monotonically with increasing Pb concentration. This non-monotonical behavior with increasing Pb could be attributed to the canting of the antiferromagnetic spins in BiFeO₃ based multiferroics.