电子型超导体Sm_(2-x)Ce_xCuO_4欠掺杂区域(0.09≤x≤0.15)的异常热电势和电阻率行为  

ANOMALOUS THERMOPOWER AND RESISTIVITY OF THE ELECTRON-DOPED SUPERCONDUCTOR Sm_(2-x)Ce_xCuO_4 (0.13≤x≤0.21)

作　　者：余旻[1] 杨宏顺[1] 柴一晟[1] 李鹏程[1] 李志权[1] 陈兆甲[1] 曹烈兆[1] 

机构地区：[1]中国科学技术大学结构开放实验室,物理系合肥230026

出　　处：《低温物理学报》2002年第3期188-192,共5页Low Temperature Physical Letters

基　　金：国家重点基础研究经费 (批准号 :19990 6 4 6 )资助项目~~

摘　　要：测量了欠掺杂区域Sm2 -xCexCuO4 (0 .0 9≤x≤ 0 .15 )多晶样品的热电势S和电阻率 ρ的温度依赖关系 .电阻率 ρ在低于 2 0 0K处斜率发生改变 ,表明低温下发生载流子弱局域化 .热电势S高温下满足线性温度依赖关系 ,随着温度降低 ,在 2 0 0～ 2 5 0K发生斜率改变 ,可以用赝能隙的开放解释 .所有的样品在 5 0K观察到一个曳引峰 ,表明载流子符号发生改变 ,由电子型转变为空穴型 .The temperature dependence of thermopower S and resistivity ρ for Sm 2- x Ce x CuO 4 polycrystalline samples in un doped area (0.09≤ x ≤0.15) has been measured. A slope change in resisitivity temperature curve was found in all samples below 200K, which indicated the localization of carriers. The thermopower S of all samples shows linear temperature dependence, and changes its slope in 200～250K, which can be explained with the open of pseudogap. A positive excitation drag contribution for thermopower S near 50K is observed in all samples, indicating the changing of the sign of carriers.

关 键 词：电子型超导体 Sm2-xCexCuO4 异常热电热 电阻率行为 欠掺杂区域 多晶样品 超导电性 

分 类 号：O511.9[理学—低温物理]