纳米晶La_(1-x)Sr_xMnO_3的溶胶凝胶法合成及表征

Preparation and characteristics of nanocrystallineLa_(1-x)Sr_xMnO_3 derived by sol-gel process

采用溶胶-凝胶法制备了纳米晶La1-xSrxMnOa,运用场发射扫描电镜(FESEM)、X射线衍射分析仪(XRD)和红外光谱分析仪(FTIR)等手段对掺杂样品的微结构、形貌等进行了分析.结果表明:当掺杂浓度x为0～0.5时,所制备的粉体为单一钙钛矿相;不同的掺杂浓度和热处理温度会使样品的晶格参数发生显著变化;La1-xSrxMnO3纳米晶粒子尺寸为10～80 nm;掺杂浓度和热处理条件对样品粒子尺寸产生很大的影响,在相同的热处理条件下,掺杂浓度高的样品晶粒尺寸较小,且掺杂浓度的增大会引起晶粒特征红外振动的红移和宽化现象.

Nanocrystalline La1-xSrxMnO3 powders were prepared by sol-gel process. The structure and particlesize of the powders were controlled by adjusting the annealing temperature. The morphologies and microstructures of the powders were analyzed by field emission scanning electron microcopy （FESEM）, X-ray diffractometry（XRD） and Fourier-transformed infrared spectroscopy（FTIR）. The results show that La1-xSrxMnO3 is single perovskite structure if doped concentration x is 0 - 0.5. The crystal lattice parameters of the sample are changed obviously with the change of doped concentration and annealing temperature. The particle-size of the powders is 10 - 80 nm and influenced greatly by the doped concentration. At the same annealing temperature, the higher doped concentration is, the smaller particle-size of the powders is. The concentration increase of doped ion will make the characteristic infrared absorb peaks to shift to higher warenumber and broader frequencies.