PZTのねじりせん断ひずみ勾配によるフレタソエレクトリック効果

摘要

物質にひずみを加えることで電気分極が発生する現象を圧電効果と呼ぶ.これに対し，フレクソェレクトリック効果はひずみの空間的な変化率，すなわちひずみ勾配に比例して電気分極が発生する効果である.フレクソエレクトリック効果は1969年にMeyerによって液晶の圧電効果として報告された現象である.液晶では形状変化を大きく取れるため，この現象による電気分極が顕著に現れる.%The authors investigated the flexoelectric effect on torsional deformation of poled PZT prism. Amount of the flexoelectric polarization in both directions along and cross to the direction of poling treatment is evaluated. Very large dielectric polarization is obtained in the direction parallel to the poling direction. In the direction perpendicular to the poling direction, large amount of difference and phase difference among output signal between each pair of electrodes are observed. Flexoelectric polarization for unpoled test piece of the same type PZT material is also investigated. It is found that from 200 to 3800 times flexoelectric coefficients are obtained for poled PZT than unpoled one. As a result, a possibility to develop a torsional vibration sensor using flexoelectric effect is shown.