Dielectric response and domain wall structure in the relaxor based mixed crystal system

用原子力显微镜（AFM）研究了Pb（Zn &lt;1/3&gt;Nb &lt;2/3&gt;）O &lt;3^-&gt; xPbTiO_3（PZN_<-x>PT;x= 0%，8%，20%）晶体的畴壁结构。在腐蚀表面上观察到铁电和铁弹畴壁结构。在菱方相中发现了锯齿形畴壁结构，并证明了在四方相和菱方相中观察到的所有铁弹畴壁结构都可以用Sapriel理论解释，得出了<-x>在没有外场的情况下，PZN_ PT（x= 8%，20%）晶体中不存在铁电带电畴壁的结论。讨论了室温下PZN-8%PT晶体相的对称性。研究还发现，即使在约50 V/cm（约为矫顽场的1/20）的弱场下，极化后PZN中的指纹图案也消失了。

Domain wall structures in Pb(Zn_<1/3>Nb_<2/3>)O_<3^->xPbTiO_3(PZN_<-x>PT;x=0%,8%,20%) crystals were investigated using atomic force microscopy(AFM). Ferroelectric and ferroelastic domain wall structures were observed on the etched surface. In the rhombohedral phase, a zigzag domain wall structure was newly found. We showed that all of the ferroelastic domain wall structures observed in the tetragonal and rhombohedral phases can be explained by the Sapriel theory, and concluded that no ferroelectric charged domain wall exists in the PZN_<-x>PT(x=8%,20%) crystal without an external field. The symmetry of the crystal phase in PZN-8%PT at room temperature is discussed. It was also found that finger print pattern in PZN disappears after the poling process even in the weak field of about 50 V/cm which is about 1/20 of the coercive field.