Ferroelastic and strain glass transition in (1-x)(Bi _0.5Na _0.5)TiO ₃-xBaTiO ₃ solid solution

The electrical and structure behaviors are somehow deviated in(1-x)(Bi _0.5Na _0.5)TiO ₃-xBaTiO ₃ (BNT-xBT), which is unusual for regular ferroelectrics whose structure transition is always accompanied with the ferroelectric one. To understand this problem, a dynamic ferroelastic measurement was used as a new way (besides ferroelectric and structure views) to determine its transition. It is found that for x<5%, they showed a typical ferroelastic phase transition, whereas it was a strain glass transition for 5%<x<8% (previously regarded as morphotropic phase boundary region). The new ferroelastic characterization provides a unique aspect to understand complex ferroelectric materials, such as BNT-xBT.