Fig. 2.

Self-consistent measurements of domain size in a PFS experiment. (a) Schematic of the tip interaction with a semiellipsoidal domain. (Inset) High-resolution PFM amplitude image of a domain wall in BiFeO₃. (b) Domain wall profile and fit by Eq. 2 for different tip models. The dotted curve is the single charge model with d = 14 nm, and solid and dashed curves are the sphere-plane model with R₀ = 15, 50, and 200 nm and ε_e = 81, 10, and 1, respectively. (Inset) Schematic of the model. (c) Domain radius deconvoluted from the hysteresis data in Fig. 1d in the point charge model. (d) Electric field on the domain boundary. (Inset) Activation energy for different models.