Skyrmion model of nano-domain nucleation in ferroelectrics and ferromagnets

A skyrmion model of nano-domain ejection from large domain walls in ferroelectrics is presented, together with data on lead germanate Pb 5 Ge 3 O 11 and comparison data on ferromagnetic iron garnet. Notable is the occurrence of a short-wavelength transverse wall instability (wiggles) prior to the nano-domain emission. This nonlinear, defect-free model is qualitatively different from all known models of ferroelectric nucleation and propagation; nucleation in ferroelectrics has almost always been viewed as inhomogeneous, initiated at static impurity or defect sites that are fixed in space; the present model is also inhomogeneous but involves nucleation at existing domain walls, which are dynamic and not fixed in space. This defect-free ferroelectric nucleation model contrasts with the frequently invoked mechanism in thin-film switching of nucleation at electrode–dielectric interfaces and thus has significant implications for the ultimate switching speed in thin-film memory devices.