超微LaFeO_3的合成及电性质研究

Study of Synthesis and Electrical Properties of LaFeO_3 Ultrafine Powders

采用溶胶－凝胶法合成了ＬａＦｅＯ３超微粉末．Ｘ射线衍射分析表明：在４５０℃已生成了纯相的ＬａＦｅＯ３超微粉末；不同温度焙烧时，结构不变，均为正交晶系．试验发现，ＬａＦｅＯ３的平均粒径随焙烧温度的增加而明显增大．初步研究了ＬａＦｅＯ３的电阻率随粒径的变化，发现ＬａｆｅＯ３的电阻率随粒径的增加而增大；导电活化能随粒径的减小而降低．

LaFeO3 ulthefine powders were prepared by sol-gel method. XRD shows that it is singlephase polycrystal LaFeO3, ultrafine powders when prepared at 450℃, the structure keep unchangeUnder firing temperatures , and it belong to orthorhombic system. The experiments indicate the meanParticle size of LaFeO3 increases remarkablely with the increase of firing temperatures . The changeof the electrical resistivities of LaFeO3, with the particle sizes has been studied. It was found thatthe electrical resistivities of LaFeO3, increase with the increase of the particle sizes , the activatedenergies for conduction decrease with the decrease of the particle sizes.