Reasearch and Development on Ferroelectric Domain Controlled Ceramics

（1）铁电材料的主要行为是由Polin Field （E）进行调查的。铁电材料评估了铅钛酸（PZT）、铅钛酸（PT）、钡钛酸（BT）、双层结构SrBi_4Ti_4O_<15>（SBT）陶瓷和Pb（Zn&lt;1/3&gt; Nb_&lt;2/3&gt;）_<0.91>Ti_O_3<0.09>（PZNT 91/09）单晶体。将轮询场（E）从0→+E→0→E→0→E→0到+E，从而使电耦合因子（k）、dielectric constant （εr）和频率constant （fc）达到度量。最小的k和εr发生在180 °域裂缝的相同E上。E due to the domain clamping corresponded to the coercive field （Ec）由poling field dependences确定。在Ec，最大fc被确认在软PZT （四边形和圆骨）、硬PZT （四边形）、BT Ceramics和PZNT 91/09单晶体的案例中。这就是为什么材料在机械上变得困难的原因是，通过领域的裂缝进行电子吸引。在硬PZT （rhombohedral）、PT、BT和SBT陶瓷中，εr和最低fc观察到E的峰值，对域旋转的阈值有相应的对应。在E中，陶瓷成为机械上软的，因为域旋转。（2）在<31>PZNT 91/09单晶体板的情况下，80%以上的K_模式的巨型机电耦合因子被确定为单域。From the investigation of the fc which corresponds to a half of the bulk wave velocity， the giant k_<31>appeared in the case of the phase with low crystal symmetry in comparison with tetragonal phase。（3）Piezoelectric bimorphs were prepared to utilize the giant k_<31>. PZNT 91/09单晶体双极显示了一种超级压电电性能，即三种等级的强度大于PZT陶瓷双极对共振和抗共振频率的影响率进行了调整。

(1)Domain behavior of ferroelectric materials was investigated by a poling field (E). Ferroelectric materials evaluated consist of lead zirconate titanate (PZT), lead titanate (PT), barium titanate (BT), Bi-layer structured SrBi_4Ti_4O_<15> (SBT) ceramics and Pb(Zn<1/3>Nb_<2/3>)_<0.91>Ti_<0.09>O_3 (PZNT91/09) single crystal. Changing the poling field (E) from 0→+E→0→E→0 to +E, the electromechanical coupling factor (k), dielectric constant (εr) and frequency constant (fc) were measured. The minimum k and εr were obtained at the same E because of the 180゜ domain clamping. The E due to the domain clamping corresponded to the coercive field (Ec) determined by the poling field dependences. At the Ec, maximum fc was confirmed in the cases of soft PZT (tetragonal and rhombohedral), hard PZT (tetragonal), BT ceramics and PZNT91/09 single crystal. It was thought that the materials became mechanically hard by the electrical attracting through the domain clamping. In hard PZT (rhombohedral), PT, BT and SBT ceramics, the peak of εr and minimum fc were observed at an E, which corresponds to the threshold of domain rotations. At the E, the ceramics become mechanically soft because of the domain rotations.(2)The giant electromechanical coupling factor of k_<31> mode over 80% had been found by realizing the mono-domain in the case of PZNT91/09 single crystal plates. From the investigation of the fc which corresponds to a half of the bulk wave velocity, the giant k_<31> appeared in the case of the phase with low crystal symmetry in comparison with tetragonal phase.(3)Piezoelectric bimorphs were prepared to utilize the giant k_<31>. The PZNT91/09 single crystal bimorph showed the superior piezoelectric properties such as three orders of magnitude larger than the PZT ceramic bimorph regarding the impedance ratio on the resonant and the anti-resonant frequencies.