与畴界有关的介电损耗、介电常数和内耗研究 1实验部分

THE STUDIES OF THE DIELECTRIC LOSS, THE DIELECTRIC CONSTANT AND THE INTERNAL FRICTION RELATED TO DOMAIN WALLS——1. Experimental Part

对KDP和TGS晶体的介电研究(f=1KHz～10KHz)表明,在Tc附近存在两个介电损耗峰(P_1′,P_2′),P_1′峰总是出现在Tc,表明它与相变有关,p_2′峰出现在Tc以下5℃左右,是与畴界粘滞运动有关的驰豫蜂,KDP晶体的内耗研究同样表明,在Tc附近存在两个内耗峰(P_1,P_2),p_1峰出现在Tc,与相变有关;P_2峰在Tc以下10℃左右,与畴有关的静滞后内耗峰,对TGS晶体,在铁电相观察到与畴界运动有关的介电常数增加,并且对此进行了讨论。

It is discovered that are two dielectric loss peaks (P_1′,P_2′)(f=1KHz to 10KHz) near Tc in KDP and TGS Crystals. The P_1′ peak akways appears at Tc and is attributed to the ferroelectric or ferroelastic phase transition, While the P_2′peak is a relaxation peak due to viscous movement of domain walls, emerging about 5℃ below Tc. The study of the internal friction (f=75KHz) also shows that there exist two peaks of internal friction (P_1,P_2) near Tc. The P_1 peak caused by the phase transition invariably appears just at Tc, while the P_2 peak at about 10℃ below Tc is related to domain walls. In addition, increase of the dielectric constant associated with domain walls is observed in the ferroelectric phasein TGS. All the experimental results mentioned above are discussed.