Hydrodynamics of Domain Walls in Multiferroics: Impact on Memory Devices

Abstract

We show that switching in ferroelectric lead germanate and lead iron tantalate zirconate titanate (PZTFT) does not resemble the equilibrium domain structure evolution of the Landau-Lifshitz-Kittel model but is instead highly nonequilibrium and similar, respectively, to the Richtmyer-Meshkov instability in liquids and the Helfrich-Hursault sliding instability in liquid crystals. The resulting nano-domain structures in PZTFT are circular or parabolic and involving folding bifurcations. These may have an undesirable impact on ferroelectric thin-film memoriesthat are also ferroelastic.