中文摘要：

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La0．67Ca0．33Mn03纳米粉末。XRD结果显示干凝胶直接在500℃下煅烧即可得到单-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（p-T）曲线上绝缘体-金属转变温度孔。附近（270K左右）非常陡的电阻率变化。

英文摘要：

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.