La1-xEuxFeAsO系统中的铕掺杂效应  

Europium doping effects in La1-xEuxFeAsO

作　　者：梅玉雪 张富翔 王操 MEI Yuxue;ZHANG Fuxiang;WANG Cao(School of Physics and Optoelectronic Engineering,Shandong University of Technology,Zibo 255049,China)

机构地区：[1]山东理工大学物理与光电工程学院

出　　处：《山东理工大学学报（自然科学版）》2020年第2期42-45,50,共5页Journal of Shandong University of Technology:Natural Science Edition

基　　金：国家自然科学基金项目(11304183)

摘　　要：研究了采用高温固相反应法合成的La1-xEuxFeAsO(x=0,0.2,0.4,0.6)系列样品中镧位掺铕的元素替代效应。基于X射线粉末衍射的晶体结构表征显示,体系的铕掺杂固溶度高达60%。随着铕含量的提高,晶胞的a轴和c轴都线性下降,说明铕离子成功替代了镧离子的晶位。电阻率随温度的变化图显示,LaFeAsO母体150 K附近的电荷密度波没有随着铕含量的提高而受到压制,同时体系在2 K以上没有观察到超导电性。磁化率测量显示,铕掺杂导致样品300 K下的磁化率线性增加。与此同时,所有掺铕样品的磁化率在150 K以上呈现明显的居里-外斯行为。经拟合得出,样品中铕离子的有效磁矩介于3.2~4.1μB之间,说明掺入的铕离子主要呈现+3价。Samples of La1-xEuxFeAsO(x=0,0.2,0.4,0.6)system are synthesized via high-temperature solid-state reaction.According to the X-ray powder diffraction profile,the Eu doping content can reach as high as 60%.In addition,both the a-axis and the c-axis decrease linearly upon Eu doping,indicating the Eu atom occupies the La site.The measurement of electronic resistivity shows that the spin density wave induced anomaly is not suppressed with increasing Eu content.No superconductivity is observed above 2 K.The magnetic susceptibility data indicate that the room temperature susceptibility signal increase upon Eu doping.Above 150 K,the susceptibility exhibits Curie-Weiss behavior.By fitting theχ-T data,the effective magnetic moment for Eu ions is determined as 3.2 to 4.1μB,which indicates the chemical valence of the Eu ion should be 3+.

关 键 词：铁基超导体 元素替代 自旋密度波 有效磁矩 化合价 

分 类 号：O513[理学—低温物理] O511.1[理学—物理]