Mechanical and thermal transitions in morphotropic PZN-PT and PMN-PT single crystals and their implication for sound projectors
Mechanical and thermal transitions in morphotropic PZN-PT and PMN-PT single crystals and their implication for sound projectors
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DOI：
10.1109/tuffc.2007.362
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发表时间：
2007-06-01
影响因子：
3.6
通讯作者：
Ewart, Lynn
中科院分区：
文献类型：
--
作者：
Amin, Ahmed;McLaughlin, Elizabeth;Ewart, Lynn
对[001]取向和极化的PZN-0.07PT和PMN-0.30PT单晶的等温压缩实验表明，机械压缩下的弹性不稳定性对应于零场铁电-铁电相变。施加适当的直流偏置磁场使两种晶体的铁电三方体态在单轴压缩下的稳定范围扩大了一倍，并保持了线弹性响应。对于PZN-PT和PMN-PT的铁电菱面体F-R态，由准静态零场应力-应变线性响应得到的杨氏模数与由小信号共振得到的杨氏模数符合得很好。高温共振测得的弹性柔量S(33)(E)在铁电菱面体(F-R)-铁电四方(F-T)相变附近呈现单调下降的杨氏模数随温度的变化。根据Devonshire理论、磁畴展开和同形相界随机械应力移动的应变计算，讨论了机械压缩后PZN-PT和PMN-PT单晶的可逆铁电-铁电相变。根据Devonshire理论讨论了机械诱导和热诱导的铁电-铁电相变轨迹。讨论了这些观测结果对声音放映机的影响。与传统的锆钛酸铅PZT8投影仪相比，制造成16元素阵列和分段圆柱形换能器的单晶tonpilz投影仪展示了单晶实现紧凑型、宽带和高源电平投影仪的卓越能力。
Isothermal compression experiments on multidomain [001] oriented and poled ferroelectric rhombohedral PZN-0.07PT and PMN-0.30PT single crystals revealed elastic instabilities corresponding to zero field ferroelectric-ferroelectric phase transition under mechanical compression. The application of an appropriate dc bias field doubled the stability range of the ferroelectric rhombohedral state under uniaxial compression for both crystals and maintained a linear elastic response. Young's modulus as derived from the quasistatic, zero field stress-strain linear response agreed well with that derived from small signal resonance for the ferroelectric rhombohedral F-R state of both PZN-PT and PMN-PT. Elastic compliances s(33)(E) as determined from high temperature resonance revealed a monotonically decreasing Young's modulus as a function of temperature in the ferroelectric rhombohedral state with a sudden stiffening near the ferroelectric rhombohedral (F-R)-ferroelectric tetragonal (F-T) transition.The reversible ferro electric-ferro electric transition of morphotropic PZN-PT and PMN-PT single crystals as accessed by mechanical compression is discussed in terms of strain calculations from Devonshire's theory, domain unfolding, and morphotropic phase boundary shift with mechanical stress. The mechanically-induced and thermally-induced ferroelectric-ferroelectric transition trajectories are discussed in terms of the Devonshire theory. Implications of these observations for sound projectors are discussed. A single crystal tonpilz projector fabricated into a 16-element array and a segmented cylinder transducer demonstrated the outstanding capabilities of single crystals to achieve compact, broadband, and high-source level projectors when compared to conventional lead zirconate-titanate PZT8 projectors.