铁电磁体Pb(Fe_(1/2)Nb_(1/2))O_3单晶高温熔液法生长及其结构特征研究  

HIGH TEMPERATURE SOLUTION GROWTH AND STRUCTURE CHARACTERIZATION OF FERROELECTROMAGNET Pb(Fe_(1/2)Nb_(1/2))O_3 SINGLE CRYSTALS

作　　者：杨颖[1] 刘俊明[2] 刘治国[2] 

机构地区：[1]南京航空航天大学材料科学与技术学院,南京210093 [2]南京大学微结构国家实验室,南京210093

出　　处：《硅酸盐学报》2005年第5期533-537,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(50332020;10021001)资助项目。

摘　　要：采用高温溶液晶体生长法,选择PbO为助熔剂,以缓慢冷却法获得过饱和度并施以温度振荡,生长出典型尺寸为3mm×3mm×3mm的铁电磁体Pb(Fe1/2Nb1/2)O3单晶。用变温X射线衍射和变温Raman光谱研究了Pb(Fe1/2Nb1/2)O3单晶的结构对称性。结果表明:Pb(Fe1/2Nb1/2)O3在实验的最低温度80K到铁电相变温度383K之间均为菱面体结构。在反铁磁相变温度Nel点以上,Pb(Fe1/2Nb1/2)O3体对角线逐渐变短,而在该温度以下,其结构没有变化。在测量的温度20～200K范围内,Raman光谱的峰位不随温度变化,说明其结构在该温度范围内没有明显变化。实验结果将有利于进一步研究铁电磁体的形成机制。Single crystals of Pb(Fe1/2Nb1/2)O3 (PFN) in size of 3 mm × 3 mm × 3 mm were grown by high temperature solution method with slow cooling from a molten flux of PbO and applied the temperature oscillation during nuclei. The X-ray diffraction from 80 K to 400 K and Raman spectra with temperature change from 80 K to 450 K were used to characterize the obtained crystal structure symmetry. The results show that PFN is in rhombohedron structure from 80 K to its ferroelectric phase transformation temperature at 383 K. Over antiferromagnetic phase transition temperature, the diagonal of PFN crystal cell gradually gets short, and below Neel critical point the structure of PFN crystal no change. The peaks of Raman spectra no change at temperature of 80-200 K, indicating that there is no change in structure within this temperature range. The experimental results are useful for the further investigation on the mechanism of ferroelectromagnets.

关 键 词：铁电磁体 铌铁酸铅 助熔剂法 单晶生长 晶体结构 

分 类 号：O782.4[理学—晶体学]