“…There are two approaches to modeling the evolution of the spatial domain structure depending on the interpretation of the domain wall: a diffuse interface [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 68 ] and a sharp interface [ 62 , 63 , 64 , 65 , 66 ]. In diffuse interface models (for example, the phase–field method), domain walls are three-dimensional objects, such as the domains themselves, and they are considered part of a continuum, whose polarization continuously changes within the domain wall.…”