Effect of La doping on dielectric properties of BiFe0.95Mn0.05O3 multiferroics

Mn and La co-doped BFO ceramics have been prepared by the sol–gel technique and their dielectric response and the ac conductivity measured as function of frequency in the frequency range from 20 Hz to 2 MHz. The dielectric data has been fitted with the Universal model and the characteristic parameters have been extracted. The maximum potential barrier heights for hopping conduction in these samples have been calculated using Correlated Barrier Hopping model. The Mn doped samples showed improvement in the dielectric constant, however, the dielectric loss, dielectric dispersion and ac conductivity were increased. The ionic space charge has been increased due to substitution of high valence Mn4+ ions at Fe3+ sites, resulting in high ion–ion coupling and high ac conductivity. The incorporation of La3+ at Bi3+ sites stabilizes the perovskite structure of BFO ceramic and helps to decrease the oxygen vacancies. Further, it has been found to recover the dielectric response and ac conductivity by reducing the ion–ion coupling in the Mn doped BFO ceramics.