中文摘要：

将纳米La0.67Sr0．33MnO3粉末和多晶SrTiO3粉末混和，在973K烧结10min后成功制备了0.5La0.67Sr0．33MnO3＋O．5SrTiO3复合物。通过XRD、SEM及PPMS研究了样品的结构和电输运性质。研究结果表明，复合物中的两个物相并没有发生化学反应，且复合物中La0.67Sr0.33MnO3的晶粒尺寸和晶粒界面相较前驱粉末保持不变。复合物和La0.67Sr0.33MnO3的磁电阻效应都显示低场和高场磁电阻效应两部分：两个样品的高场磁电阻效应基本相同，而复合物的低场磁电阻效应得到了很大增强，导电通道的减少是导致复合物低场磁电阻效应增强的原因。

英文摘要：

0.5La0.6vSr0.33MnO3 ＋ 0.5SrTiO3 composites were fabricated successfully after Lao.6vSr0.33MnO3 nanoparticles and SrTiO3 polycrystaUine powders were mixed and then sintered at 973 K for 10 min. The structures and electrical transport properties of the prepared samples were studied through XRD, SEM and PPMS measurements. The results show that there is no chemical interaction between Lao.6vSr0.33MnO3 and SrTiO3 in the composites. The grain size and grain boundary keep similar for pre La0.67Sr0.33MnO3 nanoparticles and La0.6vSr0.33MnO3 in the composites. There are two types of magnetoresistance effects, including the low-field magnetoresistance effect and the high-field magnetomsistance effect both for the composites and for pre La0.67Sr0.33MnO3. The high-field magnetoresistance is similar for the two samples. However, the low-field magnetoresistance effect is enhanced in composites because of the decrease of conduction path.