一种简便的溶胶-凝胶法制备的La_(0.67)Ca_(0.33)MnO_3纳米晶粉末的结构与性能(英文)  

Synthesis and Characterization of Nanocrystalline La_(0.67)Ca_(0.33)MnO_3 Powder by a Simple Sol-gel Method

作　　者：Mya Theingi 马吉[1] 张辉[1] 王文章[1] 易健宏[1] 陈清明[1] Mya, Theingi[1,2]; Ma, Ji[1]; Zhang, Hui[1]; Wang, Wen-Zhang[1]; Yi, Jian-Hong[1]; Chen, Qing-Ming[1]

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]仰光大学化学学院,缅甸仰光11181

出　　处：《人工晶体学报》2013年第2期345-350,共6页Journal of Synthetic Crystals

基　　金：supported by National Natural Science Foundation of China(50902062);the Scientific Research Foundation for the Returned Overseas Chinese Scholars of Ministry of Education

摘　　要：采用一种比较简单的溶胶-凝胶法在相对较低的温度下制备了钙钛矿锰氧化物La0.67Ca0.33MnO3纳米粉末。XRD结果显示干凝胶直接在500℃下煅烧即可得到单一钙钛矿相,而无需任何其他中间步骤。当煅烧温度从500℃上升到900℃时,纳米晶的尺寸相应的从30纳米长大到80纳米左右。分别采用扫描电镜和传统的四探针法表征了多晶靶材的表面形貌和电输运性能,观察到了电阻率-温度(ρ-T)曲线上绝缘体-金属转变温度TIM附近(270 K左右)非常陡的电阻率变化。Nanocrystalline powders of manganite perovskiteLa0.67Ca0.33Mn03 were prepared sol-gel method at relatively low temperature. Single nanosized perovskite phase can be produ by a simple ced when the dried gel was calcined at the temperature as low as 500 ℃ without any intermediate step that was confirmed by X-ray diffraction. The prepared calcined powders are nanoerystalline up to 900 ℃（particle size ranging from 30 nm to 80 nm）. However the erystalline particles are significantly grown （micron- sized grain） after the powders had been pressed into pellets and sintered at 1100 ℃. The morphology of bulk polycrystalline target and their electrical transport measurements were performed by using scanning electron microscope （SEM） and a conventional peaks of the resistivity vs. temperature （p-T） （around 270 K） can be observed. four probe technique, respectively. Remarkably sharp curves with insulator-metal transition temperature TIM（around 270 K） can be observed.

关 键 词：溶胶-凝胶法 纳米晶粉末 钙钛矿锰氧化物 LA0.67CA0.33MNO3 

分 类 号：TM232[一般工业技术—材料科学与工程]