Dielectric Investigations on co-substituted Bismuth Ferrite (Bi1-xLaxFe1-xMnxO3).

Bi_1-xLaxFe_1-xMn_xO₃ ceramics with x = 0.00, 0.05, 0.10 and 0.20 were synthesized by the tartaric acid modified sol-gel technique with required optimization. The co-substitution suppresses the impurities phases in bismuth ferrite which is usually observed. It was observed that the composition-driven structural transition from rhombohedral (R3c space group) to orthorhombic symmetry (Pbnm space group) plays an important role in modifying the dielectric properties of bismuth ferrite. The dielectric constant was found to be increased in La and Mn co-substituted BiFeO₃ due to significant large off-center movement of Fe³⁺ ions in the oxygen octahedra. The dispersion of dielectric constant in the frequency range of 100 Hz to 1 MHz has been analyzed by employing the modified Debye's function which suggests the contribution of multiple charge carriers in the dielectric relaxation. [ABSTRACT FROM AUTHOR]