超高介电常数非铁电单晶

Non-ferroelectric single crystal of ultra-high dielectric constant

用时域方法测量了掺钇 (Y)钨酸铅 (PWO :Y)单晶的非线性介电常数 .在不高于 15 0℃和不太高的外电场中 ,晶体具有良好的绝缘性 .其静态介电常数高达 3 94× 10 6 ,比铁电体居里点上的介电常数峰值要高得多 .时域谱分析表明 ,这种极化性质是由晶体中各种荷电缺陷的局部位移所提供的 .时域方法可定量分析晶体中缺陷的含量 .

Time domain method has been used to measure the nonlinear dielectric constants of yttrium-doped lead tungstate(PWO:Y) single crystals. Under the action of a moderate external electric field and at temperatures below 150℃, the crystal is ideally insulated. It has a static dielectric constant as high as 3.94×10 6, much higher than that of ferroelectrics at Curie point. This kind of abnormal polarization effect is ascribed to the local area displacements of several kinds of charge defects in the crystal. And time domain method can analysis these defects quantitatively.