Structural Distortion-Driven Enhancement of Ferroelectric Response in La-Modified Bismuth Titanate Layered Ceramics

Bi4-xLaxTi3O12 (x = 0.00, 0.75) ceramics were synthesized by the solid-state route to examine the effect of La3+ substitution on the structural and ferroelectric behavior of bismuth titanate. X-ray diffraction confirms a single-phase orthorhombic structure with decreasing lattice parameters and unit cell volume due to the smaller ionic radius of La3+, indicating lattice contraction. Raman analysis shows suppressed intensities of the soft 117 cm−1 Bi-site mode and TiO6 octahedral vibrations, signifying reduced structural distortion. SEM images reveal characteristic plate-like grains, with La3+ doping leading to more anisotropic morphology because of inhibited grain growth. The study of ferroelectric properties has shown that the P -E hysteresis loop is more saturated and the remanent polarization is stronger in the La3+-modified specimen and can be attributed to the stabilisation of the oxygen octahedra and reduced bismuth volatility. These results support the idea that the incorporation of lanthanum is effective in enhancing the ferroelectric property leading to the conclusion that La-doped bismuth titanate is a potential contender in memory device and multipurpose electronic applications.