Pr掺杂DyFeO_3体系的自旋重取向相变、晶格畸变与Raman光谱研究  

The study of Raman spectrum, distortion of lattice and spin reorientation phase transition on Pr doped DyFeO_3 system

作　　者：刘明[1] 曹世勋[1] 袁淑娟[1] 康保娟[1] 鲁波[2] 张金仓[1] 

机构地区：[1]上海大学理学院物理系,上海200444 [2]上海大学微结构实验室,上海200444

出　　处：《物理学报》2013年第14期447-452,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50932003;11274221;11074163);上海市教育委员会科技创新基金重点项目(批准号12YZ018;12ZZ097)资助的课题~~

摘　　要：利用固相反应法制备了Dy1-xPrxFeO3系列化合物.X射线粉末衍射晶体结构分析表明,随着Pr掺杂量x的增加,样品晶胞体积逐渐增大,晶格畸变减弱.Raman光谱测量表明稀土离子有效质量[meff=xmPr+(1-x)mDy]与晶格结构的变化共同导致该体系Raman光谱的变化.随Pr掺杂量的增加,波数小于200cm-1的振动模式基本保持不变,而波数大于200cm-1的振动模式(除420cm-1处的B3u模式外)向低频移动.磁测量结果表明,由Dzyaloshinsky-Moriya相互作用导致的宏观磁性随Pr掺杂量增加逐渐减弱.稀土离子与铁离子磁晶格的耦合作用以及晶格结构畸变的变化共同导致该体系自旋重取向相变温度在一定的掺杂量(x=0.3)前后先升高后降低.Pr doped rare-earth orthoferrites DyFeO3 is synthesized by solid state reaction. X-ray diffraction shows that the lattice parameters of Dy1-xPrxFeO3 increase and distortion of lattice decreases with Pr content x increasing. Raman spectroscopy reveals that the change of effective mass （meff ） [meff = xmPr ＋ （1-x）mDy ] together with lattice structure change results in the shift of vibration modes. With the increase of Pr content, Raman modes of wave number less than 200cm-1 remain constant, but the modes of wave number greater than 200cm-1 decrease with Pr content increasing （except the mode B3u near 420cm-1 ）. The weak ferromagnetic ordering, created by Dzyaloshinsky-Moriya interaction, is reduced with doping level increasing. The interaction of rare earth ions with Fe3＋ ion, together with the change of lattice distortion, results in the increasing of spin reorientation phase transition temperature when x 0.3 and then decreasing with Pr content increasing x increasing to over 0.3.

关 键 词：稀土铁氧体 自旋重取向 晶体结构 RAMAN光谱 

分 类 号：O474[理学—半导体物理]