【作者】 曹杉杉； 江洪建； 周惠君； 王思慧； 龚国斌；

【Author】 CAO Shan-shan,JIANG Hong-jian,ZHOU Hui-jun,WANG Si-hui,GONG Guo-bin (Dept.of Physics,Nanjing University,Nanjing 210093,China)

【机构】 南京大学物理系；

【摘要】 研究了LiNbO₃铁电体剩余极化强度与矫顽力随电压,频率和温度的变化.电压升高使剩余极化强度增大,225V附近尤为明显.225V对应LiNbO₃样品点阵结构对电畴翻转的阻碍"瓶颈".矫顽力在225V以下随电压增大迅速增大,之后增加变缓.材料内不同杂质的"钉扎"及"脱钉"使矫顽力在800V以上随电压增大分段增加.低频下铁电体物理参量不随频率明显改变.升高温度使LiNbO₃剩余极化强度与矫顽力减小,"类相变"使两参量在70℃附近发生跳变.样品内杂质与电子空位的非均匀分布以及样品片与两电极接触方式的不对称性导致电滞回线的非对称性.更多还原

【Abstract】 In this experiment,the relation between the LiNbO₃ ferroelectric properties and the outer environment was examined and analyzed.With the increase of AC voltage,the remanent polarization went up,especially rapidly around 225V,which corresponds to the bottleneck forced by the lattice structure,preventing the ferroelectric domains from being turned over.Coercive force increased quickly with the rise of voltage before 225 V,while slowed down after it.Because of pinning and unpinning contributed by various impurities,coercive force increased segment by segment after 800V.The change of AC frequency had no apparent effect on ferroelectric parameters when the frequency was low.The rise of temperature decreased the remanent polarization and coercive force of LiNbO₃,and made them drop suddenly around 70℃because of phase transition-like effect.The asymmetric distribution of impurities and the difference between the two electrodes made the hysteresis loop asymmetric.更多还原