【摘要】 本文讨论了钒掺杂La_1.85Sr_0.15Cu_1-xV_xO_4+δ体系的结构.与以往二三价元素掺杂不同,V掺杂的最高掺杂浓度较大,为0.15.精修结果表明,样品中V为+4价,并且全部替代了Cu.晶胞参数a,b随掺杂量x的增加而增加,c随x的增加减小.x=0.10时发生四方-正交相变.随掺杂含量的增加样品结构的变化在红外吸收谱中也有对应.随V含量的增加,500cm-1处的吸收峰的强度和位置都没有变化,这表明V替代在了Cu位.对于350cm-1处的吸收峰,x=0.5时在其附近左侧327cm-1处出现一个吸收峰,当x=0.10时在其右侧400cm-1处又出现一个吸收峰.400cm-1处吸收峰的出现是和四方-正交相变（x=0.10时发生四方-正交相变）相对应的.更多还原

【Abstract】 The structure of V-doped La2-xSrxCuO4+δ system has been studies in this paper.The maximum doping concentration(xc) of V for Cu is 0.15.This xc is much higher than that of the La1.85Sr0.15Cu1-xMxO4+δ(M= Fe,Co,Ni,Zn,Mg,Al and Ga) systems.The results of Rietveld refinement confirm that the V4+ indeed replaces Cu2+.The parameter a increases with the increase of x while c decreases,resulting in a progressive decrease in c/a".A Tetragonal-to-Orthorhombic phase transition occurs at V content of 0.10.The change of structure with V doping has an influence on the infrared spectroscopy.For all the samples,we can observe two absorption peaks around 500 and 350 cm-1 clearly.With V doping,the position and intensity of peak around 500cm-1 keep almost unchanged.While for peak around 350 cm-1,a peak around 327cm-1 appear when x=0.5.Then the appearance of the peak around 400cm-1 may result from the structural transition at x=0.10.更多还原