화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.102, No.10, 5997-6007, 2019
Electrical fatigue failure in (Na1/2Bi1/2)TiO3-BaTiO3 relaxor ceramics
Many devices containing ferroelectric ceramics are subjected to different loading conditions and cycles, and lack of adequate long-term reliability studies is a major concern. Here, we explore a (Na1/2Bi1/2)TiO3-BaTiO3 solid solution and study electrical fatigue as a function of amplitude, temperature, frequency, and static offset voltage (dc bias). This is expected to act as a guide for other similar material systems. Empirical relationships to quantify the dependence of fatigue on these parameters are presented. With electric field amplitude (E-max), the number of cycles to fatigue failure (N-fail) varies as: E-max x Nfaila = C, where a and C are constants whose values are different when the field amplitude is below and above the coercive field. With changes in temperature, N-fail exhibits an activated behavior and follows an Arrhenius relationship with an activation energy of 0.7 eV at an amplitude above the coercive field. In the absence of self-heating, a power law relationship is observed between N-fail and frequency of fatigue cycles at an amplitude above the coercive field. On applying a dc bias, N-fail increases by an order of magnitude, an observation that is attributed to domain switching effects. A majority of the above-mentioned effects have been explained in terms of the motion of domain walls under a given fatigue condition and their interaction with point defects.