论文部分内容阅读
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。
Perovskite manganese oxide La0.67Ca0.33MnO3 nanopowder was prepared at a relatively low temperature by a relatively simple sol-gel method. The XRD results show that a single perovskite phase can be obtained by calcining the xerogel directly at 500 ° C without any further intervening steps. When the calcination temperature rises from 500 ℃ to 900 ℃, the size of nanocrystals grows from 30nm to 80nm correspondingly. The morphology and electrical transport properties of the polycrystalline target were characterized by scanning electron microscopy (SEM) and conventional four-probe method. The resistivity-temperature (ρ-T) curves were observed near the insulator- Around) very steep resistivity changes.