MO011: Model study for tunable mechanism in ferroelectrics

Recent years, growing interests had been paid to the studies on electrical tunable ferroelectric materials and devices. Research work had been focused mainly on several aspects: tunable mechanism [1??8], material selection [9??12], loss reduction and device fabrication [13??14]. Tunable mechanism is one of the most fundamental issues among the above ones. Although several analytical or hypothetical models had been proposed for tunable ferroelectrics, such as ferroelectric intrinsic behavior [1,6], domain/polar region contribution [2??3], field induced phase transition [4] and surface layer effect [5??6], etc., a common understanding is absent yet due to the complexity of this subject. In the present author??s opinion, the tunable mechanism is a multi-scale phenomenon, and one can make various explanations for tunable mechanism with different experimental conditions, different results and different points of view. Compulsive vibration of an elastic harmonic/inharmonic vibrator is an ideal phenomenological model for describing susceptive behavior of realistic mechanical and electrical response and spectrum analysis. It??s somewhat a coordination and competition of inert motion, restoring force and damping effect, and may exhibit resonant, relaxant or drifting response [15] depending on the results of competition. The present authors adopt this tool to analysis dielectric response and field biased behavior for tunable ferroelectrics. This model builds up a picturized understanding on the physical origins of the above three kinds of dielectric response.