Structural, magnetic and electrical properties of La and Mn co-substituted BFO samples prepared by the sol-gel technique

We have examined the structural, magnetic and electrical properties of La and Mn co-substituted bismuth ferrite (BFO) samples prepared by the sol-gel technique. The XRD patterns confirm the formation of pure phase, rhombohedral structure in BFO. Manganese gave rise to spontaneous magnetization along with the clarity of magnetic hysteresis attributed to the mismatch of two magnetic ions Fe/Mn. The coercivity decreases with co substitution due to decrease in magneto crystalline anisotropy. It is observed that real part of dielectric constant (ε′) decreases with the increase in frequency. It is observed the modification in dielectric properties that may be due to La substitution which suppressed the transition of Fe3+ to Fe2+ ions, at room temperature. With La substitution in BFO there is an apparent increase in Ps, Pr and Ec values. In the case of the pristine sample BFO0, Ps reaches 0.043 μC/cm2 at the applied field (E) of 30 kV/cm with remnant polarization (Pr) 0.008 μC/cm2 and coercive field (Ec) 7.79 kV/cm. For the sample Bi0.80La0.25Fe0.95Mn0.05O3 (BFO6) Ps reaches 0.376 μC/cm2 at the applied field of 30 kV/cm with Pr 0.126 μC/cm2 and coercive field 10.3 kV/cm.