n型T'-214相超导体的结构和性质  

Structure and Properties on n-Type T'-214 Phase Superconductors

作　　者：张玉芬[1] 林勤[2] 

机构地区：[1]北京大学化学系,北京100871 [2]北京大学物理系,北京100871

出　　处：《物理化学学报》1995年第3期228-233,共6页Acta Physico-Chimica Sinica

基　　金：国家超导研究开发中心资助;国家自然科学基金;北京大学稀土材料化学及应用实验室资助

摘　　要：T＇－214相化合物R2-xCexCuO4（R为稀土离子）成为超导体决定于R3+的离子半径大小、Ce4+的取代量和化合物的热处理时的稳定性．从Raman光谱实验结果提出热处理过程中发生电荷转移Ce4+的取代引起TN（Cu）下降，当TN（Cu）降到0时，超导性出现。不同的稀土离子TN（Cu）不同，稀土离子的反铁磁性（AFM）与超导性（SC）共存。热电势的测量结果可以用双通道模型解释，n型超导体中电子与空穴共存．Electron-doped T'-R2CuO4 type superconductors have been studied by X-ray chaction, neutron diffraction, Raman, XPS, FT-IR, XAS, inelastic neutron sacttering,AC and DC magnetic measurement, resistivity measurement, specific heat and TEP measurement. A model was proposed from these experements. When R3+ was substituted with Ce4+ in the parent insulator R2CuO4, a part of doped electrons entered into CuO2 plane, but the other part was localized in the viciulty of Nd (Ce) ions. AFM ordering temperatuxe of Cu disappeares as the dopant concentration aPproaches that required for suPerconductivity (Ce=0.15). Afer annealing treatment in N2 atmosphere, the localized electrons in the vicinity of Nd (Ce) ions transfered to the CuO2 plane and becam free electrons, the concentration of charge carriers was large enough to create SC. Some questions are still not clear at present. It is necessary to perform more experements.

关 键 词：电子型 超导体 比热 热电势 拉曼光谱 反铁磁性 

分 类 号：TM26[一般工业技术—材料科学与工程] O657.37[电气工程—电工理论与新技术]