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DF: Fachverband Dielektrische Festkörper

DF 4: Multiferroics, Phase Transitions & Relaxors

DF 4.5: Vortrag

Montag, 23. März 2009, 11:40–12:00, WIL B321

Ferroelectric Domains Nucleation and Growth in BaTiO₃ — •Stefano Leoni¹, Marek Pasciak², and Salah Eddine Boulfelfel¹ — ¹Max-Planck-Institut CPfS, Dresden, Germany — ²Institute of Low Temperature, PAS, Wroclaw, Polen

Ferroelectric materials are broadly employed as capacitors and memory materials. However, even for the classical compound BaTiO₃ (BTO), the microscopic nature of the cubic paraelectric (PE) and of the ferroelectric (FE) phases and phase transformations (from cubic to tetragonal, orthorhombic and rhombohedral phases on lowering temperature) is still unclear. However, a deep understanding of the phenomenon of ferroelectricity is of top priority for further material properties control. We perform molecular dynamics simulations based on advanced schemes on the PE to FE phase transition in BTO. We elucidate ferroelectric domain nucleation and growth in detail, stressing the role of anti-ferroelectric coupling in FE domains, and show how a rescaling of critical lengths is accompanying the transition and is responsible for the ferroelectic response of the material. A full picture of domain formation with and without an external field is presented.