Lanthanum-doped BaTiO3 ceramics: Structural, dielectric, and ferroelectric properties

• Lanthanum doping in BaTiO₃ induces a structural phase transition from tetragonal to pseudo-cubic symmetry, as confirmed by XRD analysis. • SEM revealed smaller, uniform grain sizes in La-doped BaTiO₃ samples, enhancing their structural characteristics compared to undoped BaTiO₃. • Increasing la content results in a diffuse ferro-to-paraelectric phase transition, with BL₅T exhibiting relaxor-type ferroelectric characteristics. • Dielectric and ferroelectric properties were stable over a broad temperature range (−105 °C to 200 °C), with x = 30 % retaining ferroelectricity at room temperature. This study examines the structural, dielectric, and ferroelectric properties of pure BaTiO 3 and La-doped Barium Titanate (Ba 1-x La x TiO 3 , BL x T) with x = 0, 5, 10, 20, and 30 %. The samples were synthesized via the sol-gel method and subjected to comprehensive characterization using X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, differential thermal analysis (DTA), and scanning electron microscopy (SEM). Additionally, dielectric and ferroelectric properties were investigated over a temperature range of -105 °C to 200 °C. XRD revealed pure perovskite crystallization at 950 °C for 4 h. A phase transition from tetragonal (pure BaTiO 3 ) to pseudo-cubic symmetry was observed with increasing La doping. Energy-dispersive spectroscopy (EDX) suggested that La ions occupy both Ba and Ti lattice sites. SEM analysis indicated that doped samples exhibited smaller average grain sizes and uniform grain morphology compared to undoped BaTiO 3 . These structural findings were corroborated by FT-IR analysis. Dielectric and ferroelectric measurements showed distinct trends with varying La content. Samples with x = 5, 10, and 20 % displayed paraelectric behavior at room temperature, while the x = 30 % sample retained ferroelectric properties. Furthermore, an increasingly diffuse ferro-to-paraelectric phase transition was observed with higher La doping levels, and the BL 5 T composition exhibited a relaxor-type ferroelectric characteristic.