摘要
The heightened piezoelectric performance observed in most explored perovskite systems is typically at-tributed to the electric-field-induced phase transition near the morphotropic phase boundary(MPB)or polymorphic phase boundary(PPB).This study,however,unveils a distinct piezoelectric enhancement mechanism in the xPb(Nb_(2/3)Ni_(1/3))O_(3)-(1-x)Pb(Zr_(0.3)Ti_(0.7))O_(3)(PNN-PZT)system,diverging from the MPB/PPB-centered piezoelectric systems.Notably,the composition with x=0.55,positioned close to the tetragonal-pseudocubic(T-PC)phase boundary,achieves an unprecedented piezoelectric coefficient(d_(33))of 1264 pC/N,while retaining a tetragonal local structure.Importantly,on a local scale,electric fields do not in-cite phase transitions,suggesting that the exceptional piezoelectric performance in PNN-PZT stems from polarization extension near the T-PC boundary.Distinct from other mechanisms,the relative permittivity significantly increases post-poling due to this particular enhancement process.The dielectric behavior in poled specimens does not exhibit a conspicuous change at the ferroelectric-relaxor transition tempera-ture.However,both the relative permittivity and planar electromechanical coupling coefficient experience a sharp rise in the temperature range of−25℃to 25℃.This investigation underscores the pivotal role of designing compositionally-driven T-PC phase boundaries,presenting a promising avenue for enhancing piezoelectric properties in ferroelectric ceramics.
基金
financially supported by the National Natu-ral Science Foundation of China(Project No.11704301)
the Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2022JM212).
