超导体MgB_2的制备和热电势研究  

PREPARATION OF SUPERCONDUCTOR MgB2AND STUDY OF ITS THERMOPOWER

作　　者：梁彦天 赵彦立[2] 郑毅[2] 余林娟[2] 许祝安[2] 焦正宽[2] 

机构地区：[1]河南新乡师专物理系,河南省新乡市453000 [2]浙江大学理学院物理系,杭州市310027

出　　处：《低温物理学报》2001年第4期256-260,共5页Low Temperature Physical Letters

基　　金：教育部回国人员科研启动基金;国家重点基础研究专项经费资助项目

摘　　要：利用Mg扩散法制备出单相多晶的MgB2 超导体 ,其超导转变的零电阻温度为 38.5K左右 ,转变宽度小于 1K .比较了不同制备工艺对样品的密度和电阻率等的影响 ,进行了热电势温度关系的测量 .正常态电阻率温度关系均为金属型 ,可用函数a +bTn 拟合 ,n～ 2 .4 .热电势研究表明其载流子为空穴型的 ,由其斜率估算的费米能为 0 .39eV .The single phase and polycrystalline MgB 2 superconductor was successfully synthesised by Mg diffusion method. Its superconducting critical temperature (mid-point) T c ≈39.2K, and the width of transition is less than 1K. The influence of its preparation procedure on the density and electrical resistivity of the samples was studied and the temperature dependence of the thermopower was measured. The metal-like temperature dependence of electrical resistivity in normal state can be fitted with function of { a+bT n}, n ～2.4. The positive thermopower indicates that the charge carriers of MgB 2 are holes, the Fermi energy of 0.39eV was deduced by the low temperature slope.

关 键 词：超导体 MGB2 硼化镁 制备 热电势 超导电性 临界温度 

分 类 号：O511[理学—低温物理]