Study on the dynamic critical behavior of a ferroelectric heterostructure

A Landau–Devonshire theory added in Landau–Khalatnikov dynamic equation has been used firstly to explore the dynamic critical behavior of a ferroelectric heterostructure composed of two different ferroelectric films. Two identical surface transition layers within each film are assumed, and an antiferroelectric interfacial coupling between two materials is considered. One interfacial parameter β is introduced to describe the differences of physical characteristics between two constituent films, which can reflect more realistic dynamic mechanism. It is found that the ferroelectric heterostructure may exhibit multi-loop hysteresis loop and four peaks of dielectric susceptibility if the appropriate values of parameter β, antiferroelectric interfacial coupling and size of the system are selected. We obtain the critical behavior of the appearance in multi-loop hysteresis loops and four peaks of dielectric susceptibility by equilibrium action of parameter β and antiferroelectric interfacial coupling, which will provide theoretical guiding for designing the multi-state memory and miniaturized device in future.