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Barium titanate (BaTiO3) is a ferroelectric material without toxic elements, whose ferroelectric properties such as permittivity, coercive field, and spontaneous polarization are affected by the nucleation of domains of reversed polarization and the motion of domain walls. Dislocations can act as obstacles to domain‐wall migration or as active sites for domain nucleation. Thus, studies are conducted on the utilization of dislocations to improve the ferroelectric properties of BaTiO3. However, the atomistic mechanism of domain nucleation around the dislocation core is still unclear. In this article, a machine learning (ML) potential is developed to study the influence of dislocations on domain nucleation. The potential is trained using an active‐learning approach to ensure accuracy in the bulk properties of the ferroelectric and paraelectric phases, as well as in the dislocation core structures in BaTiO3. Molecular dynamics simulations using the ML potential show that the influence of dislocations on polarization reversal depends on the directional relationship between the external electric field and the dislocation. Furthermore, strong local polarizations exist surrounding the dislocation core, owing to vacancies in the core. These polarizations can act as both domain nucleation sites and obstacles for domain migration when ordered along the dislocation line. [ABSTRACT FROM AUTHOR]

BaTiO3 (BT), a lead‐free ferroelectric material, is employed in energy‐conversion devices, including actuators and capacitors. However, its ferroelectric properties, such as the piezoelectric coefficient and Curie temperature, fall short of those of harmful lead‐based ferroelectrics, such as Pb(Zrx, Ti1−x)O3. In this study, a BT crystal is examined under biaxial strain (i.e., strain in the a‐ and b‐directions of the unit cell) to investigate the alterations in its ferroelectric properties. The piezoelectric coefficient, Curie temperature, polarization magnitude, and coercive electric field are calculated under varying biaxial strains using molecular dynamics simulations. The simulations utilize a core–shell‐type interatomic potential developed from first‐principles electronic structure calculations. In the findings, it is revealed that 1) the Curie temperature, polarization magnitude, and coercive electric field increase, whereas the piezoelectric coefficient in the c‐direction decreases under biaxial compression; 2) modifications in the ferroelectric properties depend on the area of ab‐plane and not on its aspect ratio. Comprehensive analyses of the Ti‐displacement distribution offer microscopic insights into strain‐induced shifts in ferroelectric properties. [ABSTRACT FROM AUTHOR]