Structural, magnetic, vibrational and impedance properties of Pr and Ti codoped BiFeO_3 multiferroic ceramics

摘要

Single-phase (Bi_(1-x)Pr_x)(Fe_(1-x)Ti_x)O_3 ceramics (X=0.03, 0.06, and 0.10 as BPFT-3, BPFT-6 and BPFT-10, respectively) were synthesized by conventional solid state reaction method. The effect of varying Pr and Ti codoping concentration on the structural, magnetic, dielectric and optical properties of the BPFT ceramics have been investigated. X-ray diffraction indicated pure rhombohedral phase formation for BPFT-3 and BPFT-6 ceramics, however, a structural phase transition from a rhombohedral to an orthorhombic phase has been observed for BPFT-10 ceramic. The maximum remnant magnetization of 0.1824 cmu/g has been observed in BPFT-6. With increasing codoping concentration the room temperature dielectric measurements showed enhancement in dielectric properties with reduced dielectric loss. UV-vis diffuse reflectance spectra demonstrated the strong absorption of light in the visible region for a band gap variation 2.31-2.34 eV. Infrared spectroscopy indicated the shifting of Bi/Pr-O and Fe/Ti-O bonds vibrations and change in Fe/Ti-O bond lengths. Decrease in the conductivity on increasing Pr and Ti concentration in BFO is attributed to an enhancement in the barrier properties leading to suppression of lattice conduction path arising due to lattice distortion as confirmed from impedance analysis.