SmCoO3的固相合成及性质

以Sm₂O₃和Co₂O₃为原料，使用高温固相反应法合成SmCoO₃正交钙钛矿化合物，采用X射线衍射、Raman谱、热膨胀仪和高温电导等测试技术对样品进行了结构和性能研究.结构分析表明，Sm₂O₃与Co₂O₃在1353K附近可以进行固态反应，形成单相性很好的SmCoO₃正交钙钛矿相.高温电导测量显示单相SmCoO₃随温度升高由绝缘体向半导体转变，Arrhenius图表明绝缘体—半导体转变点在470K附近.单相SmCoO3的热膨胀系数在873K以上为2.17×10^-5K^-1，和掺杂LaGaO₃相近，但明显大于SDC（Ce_0.85Sm_0.15O₂）的热膨胀系数.

Solid-state Synthesis and Properties of SmCoO3

The solid-state reaction method was used to prepare the perovskite oxide SmCoO₃.The structure and properties of the samples have been investigated by XRD，Raman spectral techniques and DC measurements and so on.The XRD and Raman spectra show that the mixtures of Co₂O₃ and Sm₂O₃ can form a single-phase perovskite oxide SmCoO₃ by solid-state reaction around 1353K.The clearly observed band in the room temperature Raman spectra of single-phase SmCoO₃ is at 140~175cm^-1,，which is assigned to the stretching of Sm—O and the winding of O—Sm—O.The single-phase SmCoO₃is an insulator below 600K，and the conductivity is enhanced obviously with temperature increasing above 600K.This may be explained by the fact that an insulator to semiconductor transition occurs around 470K.The thermal expansion coefficient（2.17×10^-5,K^-1,）of the single-phase SmCoO₃is approximately equal to that of doped LaGaO₃，but bigger than that of SDC（Ce_0.85Sm_0.15O₂）above 873K.