不同元素掺杂对复合晶体Sr14(Cu1-yMy)24O41(M=Zn，Ni，Co)结构的影响

Effects of different element doping on the structure of composite crystal Sr_(14)(Cu_(1-y)M_y)_(24)O_(41)(M=Zn,Ni,Co)

用常规的固相反应法制备了Zn2+,Ni2+,Co3+掺杂的3组复合晶体Sr14(Cu1-yMy)24O41(M=Zn,Ni,Co)系列样品。选区电子衍射研究表明,这些样品的自旋链亚结构的衍射点都出现了在a*和b*方向上扩展成衍射线的现象,而仅由自旋梯子亚结构产生的衍射斑点仍保持明锐。随着掺入离子的电子总自旋的增大,自旋链亚结构的衍射斑点扩展成衍射线的现象加重。掺入Co3+离子的复合晶体Sr14(Cu1-yCoy)24O41中对应于自旋链亚结构的衍射斑点已完全扩展成垂直于c*的漫散射条纹。掺Co样品[001]带轴高分辨像显示,两套亚系统沿[001]方向的投影在a和b方向上的周期非常完整。这表明,Sr14(Cu1-yCoy)24O41的自旋链亚结构仅在沿着c发生了初始相位无序。而掺入离子的电子总自旋的不同使这种初始相位无序的程度不同。

The Zn^2＋ , Ni^2＋ and Co^3＋ doped Sr14（Cu1-yMy）24O41（M=Zn,Ni,Co） composite crystals were synthesized by standard solid state reaction method. Selected area electron diffraction experiments showed that the diffraction spots corresponding to the spin-chain substructure were extended to diffuse scattering fringes along a ^＋ and b^＋ directions, while the diffraction spots produced merely from the ladder substructure were still very sharp. Such a phenomenon that diffraction spots were extended to diffuse fringes became more severe as the total spin of the ion doped into the composite crystal increased. In the Co^3＋ doped samples, the diffraction spots were completely extended to diffuse scattering fringes perpendicular to the c^＋ axis. The HREM image of the Co doped sample along[001 ] direction shows that the projection along[001 ] direction of the structure is highly periodic in both a and b directions, which implies that the initial phase disordering of the spin chain substructure of Srl4 （Cu1-yCoy）24O41 occurred only in the c direction. The difference in the total spin of the doped ions made the initial phase disordering degree different.