电子束辐照下LaCoO3薄膜中产生的新结构  

A new modulated structure of LaCoO3 thin film induced by electron beam irradiation

作　　者：管翔翔 沈希[1] 王伟鹏 张静[1,2] 姚湲 孙继荣[1,2] 禹日成[1,2] GUAN Xing-xiang;SHEN Xi;WANG Wei-peng;ZHANG Jing;YAO Yuan;SUN Ji-rong;YU Ri-cheng(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 101407,China)

机构地区：[1]中国科学院物理研究所,北京凝聚态物理国家研究中心,北京100190 [2]中国科学院大学物理科学学院,北京101407

出　　处：《电子显微学报》2020年第5期498-502,共5页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(Nos.11874413,11934017);科技部国家重点研发计划(Nos.2017YFA0206200,2016YFA0300701,2018YFA0208402);中国科学院先到计划B(No.XDB33030200)。

摘　　要：利用球差校正扫描透射电子显微学方法,研究了在电子束辐照作用下LaCoO3/La2/3Sr1/3MnO3/LaCoO3三层膜中LaCoO3的结构演化。在实验中观察到一种新的调制结构,确定了其在所观察截面上调制结构的晶胞为:a’=√5a0,b’=√2a0,夹角约为71.57°(a0为LaCoO3赝立方结构的晶胞参数)。环形明场像的结果表明,LaCoO3在电子束辐照下由具有3a0周期的暗条纹结构演化为具有新周期的调制结构,并伴随氧空位的重新分布。本文研究的LaCoO3薄膜中的结构演化是应变能、电子束辐照能量以及氧空位有序分布的形成能共同作用的结果,同时也为电子束辐照调控LaCoO3薄膜的磁性提供了实验参考。By using scanning transmission electron microscopy,the structural evolution of LaCoO3 in LaCoO3/La2/3 Sr1/3 MnO3/LaCoO3 film was investigated under the action of electron beam irradiation(EBI).A new modulated structure is observed and the unit cell of the modulated structure in the projection plane along the transmission direction is determined as a’=√5 a0,b’=√2 a0,angle is about 71.57°(a0 is the lattice parameter of the LaCoO3 in the pseudo-cubic structure).The result of annular bright field image reveals that the redistribution of oxygen vacancies occurs in the transition from dark stripes structure with 3a0 periodicity to the new modulated structure under EBI.In this study,the microstructural change is the result of the competition among strain energy,EBI induced energy and the forming energy of oxygen vacancy with ordering distribution.This work offers experimental reference for tuning the magnetism in LaCoO3 film system.

关 键 词：LACOO3 电子束辐照 调制结构 氧空位 

分 类 号：TG115.215.3[金属学及工艺—物理冶金] O741.5[金属学及工艺—金属学]