摘要:
利用固相反应法制备了Sr_(14)Cu_(24)O_(41)及其系列B位掺杂Sr_(14)(Cu_(0.97)M_(0.03))_(24)O_(41)(M=Zn,Ni,Co)的样品.X射线衍射分析显示,所有样品均为纯相,晶格常数a与c没有明显的变化;Zn掺杂样品晶格常数b没有明显变化,而Ni,Co掺杂样品晶格常数b分别稍有增加.选区电子衍射研究揭示:磁性元素Ni,Co及非磁性元素Zn掺杂,可能主要替代了Sr_(14)Cu_(24)O_(41)结构中自旋链上的Cu原子,从而影响了自旋链上的dimer排列,破坏电荷有序超结构.电输运测量显示:Zn~(2+),Ni~(2+),Co~(3+)离子掺杂样品的电阻率降低,但仍体现半导体行为,所有的掺杂样品都存在一个渡越温度T_ρ,当T>T_ρ时,其导电机理是以单空穴热激发导电占主要地位,在T
Abstract:
Polycrystalline samples of Sr_(14)(Cu_(0.97)M_(0.03))_(24)O_(41)(M=Zn,Ni,Co) were synthesized by standard solid state reaction method.All samples are single phase as identified by X-ray diffraction, no regular shift of lattice parameters a, c is found, but the lattice parameter b increases slightly with doping magnetic ions Ni and Co, and has no change with doping non-magnetic ion Zn, respectively.Selected area electron diffraction experiments show that Zn, Ni and Co ions may substitute for Cu ions in the chain.All the doping compounds are still semiconductors and have a crossover temperature T_ρ like the parent phase Sr_(14) Cu_(24)O_(41).The influence of magnetic ion Ni or Co doping on the resistivity is smaller than that of non-magnetic ion Zn doping, while the influence of non-magnetic ion Zn doping on crossovertemperature is smaller than that of magnetic ion Ni or Co doping.