La_(0.67)Sr_xMnO_(3-δ)的制备及表征

利用固态反应法制得名义组份为La0 .67SrxMnO3-δ(x=0 .33,0 .2 8,0 .2 3,0 .1 8和 0 .1 3)的多晶样品。X射线衍射表明当 0 .1 8≤x≤ 0 .33时样品是单相的钙钛矿型结构 ,这表明A位可以存在较多的空位。红外吸收光谱显示 ,随着A位空位增多 ,MnO6 八面体基团的伸缩振动模 (波数约为 60 0cm- 1 )的红外活性增强 ,同时电声子散射也随之增强。

The Preparation and Characterization of La0.67SrxMnO3-δ

The polycrystalline samples with nominal compositions La 0.67 Sr xMnO 3-δ (x=0.33,0.28,0.23,0.18 and 0.13) are synthesized by solid state reaction. The x-ray diffraction indicates that the obtained samples are single phase with perovskite structure in the doping range of 0.33≥x≥0.18, and that the perovskites can tolerate a considerable proportion of vacancies on A site. The infrared absorption spectra demonstrates that the stretching vibration mode with frequency around 600cm -1 for MnO 6 octahedron is activated effectively with increasing vacancies on A sites, and accordingly electron-phonon scattering is enhanced.