Surface charge mediated polar response in ferroelectric nanoparticles

Interfacial phenomena in dielectric-ferroelectric composites have significant potential for promoting novel properties. Here, we utilize a dynamic Landau-Ginzburg-Devonshire methodology to elucidate the influence of an electrostatic self-interaction on the polarization behavior of spherical ferroelectric nanoparticles embedded in a dielectric matrix. By varying the particle volume and the dielectric permittivity of the surrounding medium, phase boundaries between states with polarization patterns exhibiting monodomains, structural, and electrical polydomains, and vortex-like topologies are observed in isolated particles. Under an applied bias, incomplete screening of surface charges leads to a size-dependent, monodomain-to-vortex topological phase transition that suppresses macroscopic polarization. The vortex topology observed in the polarization-suppressed region of the hysteresis originates from the minimization of surface charges at the particle-matrix interface, resulting in linear behavior and double hysteresis loops. Published under an exclusive license by AIP Publishing.