Dielectric and Ferroelectric Behavior of La-Doped Bi₄Ti₃O₁₂ Prepared by Mechanical Alloying

Lanthanum-doped bismuth titanate (BLT) was synthesized via high-energy ball milling to improve its dielectric and ferroelectric properties. Structural analysis using X-ray diffraction confirmed the successful incorporation of La³⁺ into the Bi₄Ti₃O₁₂ lattice, resulting in reduced crystallite size (BIT 15.28 nm and BLT 16.02 nm ) and enhanced lattice distortion. Scanning electron microscopy revealed particle sizes of approximately 11–12 nm, while TEM confirmed nanoscale crystallinity with less than 20 nm particle dimensions. Raman spectroscopy further validated structural modifications, including TiO₆ octahedral distortions induced by La substitution. The dielectric performance showed a significant increase in the dielectric constant from 142 (BIT) to 176.3 (BLT) at 100 Hz, alongside reduced dielectric loss (BIT 1.89, BLT 2.18), attributed to enhanced space-charge polarization at grain boundaries. Ferroelectric hysteresis loops demonstrated improved remnant polarization, increasing from 5.19 μC cm⁻² (BIT) to 6.94 μC cm⁻² (BLT), while retaining a low coercive field. The study highlights the potential of La-doped Bi₄Ti₃O₁₂ as an efficient dielectric and ferroelectric material for high-performance applications in non-volatile memory devices and high-temperature capacitors. Quantitative results validate the effectiveness of mechanical alloying as a cost-efficient and scalable synthesis route, offering a platform for future optimization of dopant concentrations and processing conditions to maximize material performance.