Correlation of Structural Properties and Ferroelectricity in Cobalt and Iron Co‐Doped Aurivillius Ceramics Based on Rietveld Refinement Analysis

Abstract This research examines the structural and ferroelectric characteristics of lanthanum‐modified Bismuth Titanate (Bi 4 Ti 3 O 12 ) ceramics by co‐doping with cobalt (Co 3+ ) and iron (Fe 3+ ). Structural refinement demonstrates that the La 3+ substitution at Bi 3+ significantly decreases titanium–oxygen bond lengths, augmenting the covalent character crucial for altering the ferroelectric response. Incorporating Co 3 ⁺ and Fe 3 ⁺ induces defects, causing a reduction in maximum polarization from around 10 µC cm − 2 to about 4.88 µC cm − 2 . Structural examinations indicate an orthorhombicity of around 7.64×10 −3 in the BLaT sample and 7.49×10 −3 in the BLaT‐FC2 sample, corresponding with their respective polarization tendencies. A defect pinning hindered the motion of the domain wall in BLaT‐FC2, resulting in a constricted (P–E) hysteresis loop. Nevertheless, repeated electrical cycling enhances ferroelectric responses, allowing greater polarization alignment through progressive defect mitigation. As a result, structural defects and functional properties are dynamically interacting. The results highlight the significant impact of defect dynamics and structural changes on controlling the ferroelectric performance of Bi‐based layered structure ceramics. This indicates that deliberate doping strategies and defect engineering can substantially enhance the reliability and effectiveness of ferroelectric materials for advanced electronic applications.