超微LaMnO3的合成与导电性研究

采用柠檬酸盐热解法合成了ＬａＭｎＯ３超微粉末。经Ｘ射线衍射分析表明，所合成的ＬａＭｎｏ３为单相，属于六方晶系。实验发现，ＬａＭｎｏ３的平均粒径随焙烧温度的增加而明显地增大。首次研究了超微ＬａＭｎＯ３的电阻率随粒径的变化，发现ＬａＭｎＯ３的室温电阻率随粒径的增加而减小，导电活化能随粒径的减小而变小。

Study of Synthesis and Electrical Conductivity of LaMnO_3 Ultrafine Powders

aMnO3 ultrafine powders were prepared by pyrolysis of amorphous citrate.XRD indicates the single phase of LaMnO3 has been synthesized. They are hexagonal in the structure. The experiments show that the mean particle size of LaMnO3 increases greatly with the increase of firing temperatures. The change of the electrical resistivities with the particle sizes has been first studied for the LaMnO3 ultrafine powders. It was found that the electrical resistivites of LaMnO3 at room temperature decrease with the increase of particle sizes, the activated energy for conduction decreases with the decrease of the particle sizes.