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利用助溶剂法 ,已经生长出 15mm× 2 5mm× 6 0mm的大尺寸NdP5O14 (NPP)晶体。用高分辨X射线衍射术对自发应变及铁弹畴结构进行了研究。对几个不同的反射 ,可在其摇摆曲线上观测到由基体畴和铁弹畴之间的取向差导致的反射峰的分离。通过反射峰分离的特点 ,可以确定铁弹畴结构。NPP晶体中大多数铁弹畴为a型畴 ,b型畴只出现在严重形变的区域。基于NdP5O14 晶体畴结构 ,我们分别计算了 80 2 ,40 2和 2 0 4反射的峰分离量。实验测量结果符合计算结果。另外 ,通过测量基体畴和铁弹畴的 80 0反射的峰分离量我们确定了NdP5O14 的自发应变是 0 .0 0 82。通过结构和对称性分析 ,我们对这种晶体的畴结构进行了详细讨论。
Large size NdP5O14 (NPP) crystals of 15 mm × 2 mm × 600 mm have been grown using the cosolvent method. High-resolution X-ray diffraction was used to study the spontaneous strain and the iron-based domain structure. For several different reflections, the separation of the reflection peaks caused by the difference in orientation between the base domain and the iron-bomb domain can be observed on its rocking curve. By the characteristics of the reflection peak separation, the iron-based domain structure can be determined. Most of the ferroalloy domains in NPP crystals are a-type domains, while b-type domains only appear in severely deformed regions. Based on the NdP5O14 crystal domain structure, we calculated the peak separations of 80 2, 40 2 and 20 4, respectively. Experimental measurement results in line with the calculation results. In addition, we determined that the spontaneous strain of NdP5O14 is 0.00002 by measuring the peak separation of the 80 0 reflections of the host domains and the ferroelastic domains. Through the structure and symmetry analysis, we have discussed the domain structure of this kind of crystal in detail.