Phase-field modeling of the impact of charged defects on hysteresis loops in PTO ferroelectric thin films

Using a phase-field modeling approach based on Landau–Ginzburg–Devonshire theory, we investigate the influence of charged point defects on the hysteresis characteristics of ferroelectric thin films. A systematic parametric study is carried out to quantify the dependence of the remanent polarization and coercive field on the defect charge magnitude and the effective defect density. It is shown that an increase in the defect charge or defect density leads to a progressive narrowing of the hysteresis loop, up to a complete suppression of ferroelectric properties due to the development of internal depolarizing fields. Phase diagrams are constructed, on which a critical boundary is identified that separates a stable ferroelectric phase from paraelectric-like behavior. The results are relevant for the design of highly reliable ferroelectric nanoelectronic devices and open up prospects for targeted defect engineering to control the functional characteristics of ferroelectric thin films.