Laminated Modulation of Tricritical Ferroelectrics Exhibiting Highly Enhanced Dielectric Permittivity and Temperature Stability

摘要

Ferroelectric materials with large dielectric response and high temperature-stability have found significant applications in advanced electronics and electrical power/storage equipment. The effective approaches explored up to now mainly focus on improving dielectric response by employing the phase instability caused by the ferroelectric transition. Nevertheless, one inherent shortcoming is that the enhancement of dielectric permittivity is at the expense of the deterioration of its temperature stability. Here, a strategy that successfully achieves both enhanced dielectric response as well as excellent temperature reliability (with epsilon(r )approximate to 2 x 10(4) from 30 to 85 degrees C) by designing a laminated structure of tricritical ferroelectrics (LTF) with successive Curie temperatures is proposed. Moreover, the improvement in dielectric performance triggers the temperature-stable energy-storage performance as well as electrocaloric property in LTF specimens. Further microstructure investigation and phase-field modeling reveal that these remarkable properties of laminated layers originate from the successive occurrence of tricritical transition with a nanodomain structure in a wide temperature range. The findings may shed a new light on developing advanced ferroelectrics with high performance and thermal reliability.