摘要
采用溶胶-凝胶法制备了La_(0.5)Sr_(0.5)Mn_(1-x)Co_xO_3(x=0.1～0.5)的系列样品,通过XRD、SEM和VSM对样品进行了表征。结果表明:随着Co^(3+)离子掺杂量的增加,样品的结构由正交晶系向单斜晶系转变,这种现象的产生是由于Co^(3+)离子半径(r=0.754nm)与Mn^(3+)离子半径(r=0.68nm)不匹配造成的。样品形貌为均匀的球形,平均直径50nm左右。样品的居里温度和居里温度附近的磁熵变随Co^(3+)掺杂量的增加先下降后升高,这是由于参加双交换作用的离子数目减少和结构畸变导致的。
La0. 5 Sr0. 5 Mn1-x CoxO3 （x=0. 1-0.5） powders are prepared by sol-gel techniques. The characters of powder are characterized by X-ray diffraction, SEM and VSM. An orthorhombic-monoclinic transition of La0.5Sr0.5- Mn1-xCoxO3 structure with x is observed. This can be ascribed to the dismatch of radius between Co^3＋ （r=0. 754nm） and Mn^3＋ ion（r=0.68nm）, The morphology of the powder is homogeneous sphericity with average diameter of about 50nm, The Curie temperature and magnetic entropy of La0.5 Sr0.5 Mn1-x CoxO3 powders decrease with the increase in dopant content x, and then increase. It is suggested that it is related to the ions amount reduction of double exchange effect and structural distortion etc.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2008年第1期134-136,共3页
Materials Reports
基金
黑龙江省博士后基金(LRB05-201)
哈尔滨工程大学基础研究基金项目(HEUFT05019)
教育部博士学科点专项基金(20050217019)
