自旋梯子化合物Sr_(14-x)Ca_xCu_(24-y)Co_yO_(41)中的Co替代效应  

Cobalt Substitution Effects in the Spin Ladder Compound Sr_(14-x)Ca_xCu_(24-y)Co_yO_(41)

作　　者：王清波[1] 姚凯[2] 何咪[3] 朱增伟[3] 许祝安[3] 

机构地区：[1]中国地质大学,湖北武汉430074 [2]新乡学院,河南新乡453000 [3]浙江大学,浙江杭州310027

出　　处：《稀有金属材料与工程》2010年第A01期11-14,共4页Rare Metal Materials and Engineering

基　　金：中国地质大学(武汉)优秀青年教师资助计划项目(CUGQNL0913)

摘　　要：系统地研究单相Co掺杂自旋梯子化合物Sr14-xCaxCu24-yCoyO41(x=9:y=0,1,2,3;x=6:y=0,3)系列样品的晶体结构、电阻率以及热电势随Co含量的变化。随着y(Co)掺杂量的增加,晶格常数a,b,c几乎线性增加。电阻测量发现所有样品的电阻率温度关系均为半导体型,电阻率随着Co掺杂量的增加而增加。除了x=9,y=0样品外,其他样品的电阻率均可以用热激活公式ρ=ρ0exp(Δ/kBT)拟合。热电势测量发现,x=9,y=0样品的热电势显示金属型行为,其余样品均显示半导体行为,并且热电势随Co含量增加而明显增大。认为Co掺杂引入了无序、电子,并且引起空穴载流子由导电性较好的自旋梯子向导电性较差的自旋链的转移,从而减少参与导电空穴的数目,使得能隙、电阻率以及热电势增加。Abstract： Cobalt substitution effects in the single phase spin ladder compounds Sr14-xCaxCu24-yCoyO41 was studied. The crystal structure, the resistivity and the thermoelectric power change with various values y（Co） were researched. All lattice parameters of Sr14-xCaxCu24-yCoyO41 increase almost linearly with the increase in y（Co）. T dependence of the electrical resistivity of all samples is semiconducting. The value of the resistivity increases with the increase of cobalt concentration. The resistivities can be fit by the thermal active equation ρ=ρ0exp（△/kBT） except for the sample of x=9, y=0. Through thermoelectric power measurements, we find that the sample of x=9, y=0 exhibit metallic behavior while the others exhibit semiconductive behavior. Cobalt substitution induces disorder and electron. Lattice constants increasing make the holes transfer from the better conductive spin ladder to the chain. Those lead to the increase of activation energy, resistivity, and thermoelectric power.

关 键 词：自旋梯子化合物 CO掺杂 热电势 

分 类 号：O641.1[理学—物理化学]