Defect-mediated structural and magnetic behavior of BaTi1-xFexO3 (0.02 ≤ x ≤ 0.10) synthesized via sol-gel method

This work investigates the defect-mediated multifunctional behaviour of iron-doped barium titanate (BaTi_1-xFe_xO₃; 0.02 ≤ x ≤ 0.10), synthesized via the sol-gel method. Rietveld refinement confirms the retention of the tetragonal perovskite phase (P4mm), with a notable in-plane lattice expansion from x = 0.02 to 0.08, attributed to Fe³⁺ substitution and oxygen vacancy formation. Raman and FTIR analyses reveal phonon broadening and Ti-O bond distortions due to defect-phonon coupling. Thermal analysis shows <4 % weight loss, indicating high thermal stability. Magnetic measurements exhibit weak room-temperature ferromagnetism and enhanced magnetization at 3 K (M_s ≈ 2.00673 emu/g), with a Curie-Weiss temperature of θ ≈ 434 K, signifying short-range ferrimagnetic interactions. Mössbauer spectroscopy confirms Fe³⁺ in symmetric (93.01 %) and vacancy-associated distorted (6.99 %) sites. These findings demonstrate the efficacy of Fe doping in tailoring structure and magnetism via defect engineering, positioning BaTiO₃ as a viable lead-free candidate for magnetoelectric and spintronic applications.