不同稀土离子掺杂对Ln0.8Sr1.2CoO4结构与磁性的影响.pdf

第32卷第2期
山东建筑大学学报
Vol 32 No.2
2017年4月JOURNALOFSHANDONGJIANZHUUNIVESITY
2017
文章编号:173-7644(2017)02-0132-05
不同稀土离子掺杂对 Lnog Sr,2CoO
结构与磁性的影响
毛金花
(山东建筑大学理学院,山东济南250101)
摘要:K2NiF4型钴氧化物的自旋态转变及准二维层状结构使其具有独特的磁学性质,开展不同稀土离子掺杂对
Ln Sr2Co04结构与磁性的影响研究可吏好地揭示维度特性对其物理性质的影响。文章基于固相反应法合成
的 Ln. Sr2CoO(Ln=Ia,Nd,Gd)多晶样品,围绕空穴掺杂对结构的影响及其低温下复杂的磁性,通过物性测
试系统对系列样品进行直流磁化强度的测试与分析,阐明了不同稀土离子掺杂对该体系结构与磁性的影响。
结果表明:随着体系中A位平均离子半径的减小,晶胞参数减小, Jahn- Teller畸变增大, Griffiths相温度由
214.9K降低到159.9K,外斯温度由89.4K降低到7.1K,表明体系的铁磁性被抑制而反铁磁性逐渐增强;低
温区稀土离子对磁化强度的贡献愈加明显,Cd。sSr12CoO。样品的磁矩高达36.42x10-3emu/mol;
nsSr.CoO体系内部化学压力效应的改变诱导更多低自旋态Co'稳定,进而导致磁状态的改变。
关键词:离子掺杂;钙钛矿;钻氧化物;磁性
中图分类号:0469
文献标识码:A
Effects of different rare earth ions on structure and magnetic
properties of Lngsr,2 Coo,
Mao Jinhua
(School of Science, Shandong Jianzhu University, Jinan 250101, China
Abstract K,Nif type cobalt oxide usually shows many unique magnetic properties due to spin state
transition and its quasi two dimensional layered structure. On account of hole doping effeet on
structure and their intricate low temperature magnetic properties, the Lnos Sr,2 Co0(In=La, Nd
Gd samples were prepared with conventional solid state reaction method. The dc magnetization was
carried out using the physical properties measurement system of quantum design. The relationship
between the structure and magnetic properties in Ino s Sr,2 Coo was systematically studied. With the
decrease of the average A-site ionic radius, the lattice parameters decrease, the Jahn-teller distortion
is enhanced, the Griffiths temperature decreases from 214.9 K to 159.9 K, and the Weiss temperature
decreases from 89.4 K to 7. 1 K, which suggests the suppression of ferromagnetism as well as the
enhancement of antiferromagnetism. In the lower temperature region, the contribution of rare earth
ions to the magnetization of samples is more obvious. The magnetization of Gdo g> Coo, reaches to
36.42 emu/mol. Meanwhile, the change of chemical pressure effect leads to more low spin state of
Co"ions in Lno g Sr,2 Coo], which results in the change of the magnetic state
Key words: perovskite; ion-doping; cobalt oxide; magnetism
改稿日期:2017-02-15
基金项目:山东建筑大学博土基金项目(XNBS1267)
作者简介:毛金花(1981-),女,讲师,博上,主要从事磁性等方面的研究,E-mail:maojinhua(@sdjzu.edu.cn