晶体畴反转过程中畴壁运动与极化电流特性研究

The characteristics of domain walls growing and polarization current in the process of ferroelectric domains inversion

为了解晶体畴反转的动力学过程,利用马赫-曾德干涉实验系统,研究了外电场极化下掺镁铌酸锂和纯净铌酸锂晶体在畴反转过程中的畴壁运动和极化电流特性。实时记录了掺镁7 mol%、掺镁5 mol%铌酸锂和纯净铌酸锂晶体在畴反转过程中的畴壁特征和极化电流变化情况,发现离散的畴壁速度脉冲伴随着离散的极化电流脉冲,连续的畴壁速度脉冲对应着连续的极化电流脉冲。掺镁铌酸锂晶体正向反转和纯净铌酸锂反向反转的畴壁速度变化和极化电流变化比较尖锐,而掺镁铌酸锂晶体反向反转和纯净铌酸锂正向反转的畴壁速度变化和极化电流变化比较缓和。最后对实验现象进行了解释。

To understand the dynamics feature of ferroelectric domains inversion, a MachZehnder interference system was set up to study the characteristics of domain wall motion and polarization cur rent in domains inversion process in pure LiNbO3 and in MgOdoped LiNbO3under electric field po larizing. The domain wall patterns and the polarization current were recorded in realtime in domains inversion process for 7 mol% MgOdoped LiNbO3, 5 mol% MgOdoped LiNbO3and pure LiNbO3. It was found that discrete domainwall velocity pulse corresponds to a discrete polarized current pulses and continuous domain wall velocity pulse corresponds to the continuous polarized current pulses as well. Domain wall motion and polarization current of the forward inversion of MgOdoped LiNbO3 and the reverse inversion of pure LiNbO3 change sharperly. But domain wall motion and polarization current of the reverse inversion of MgOdoped change moderately. The experiment results are LiNbO3 and the forward inversion of pure LiNbO3 explained.