后处理工艺及氧含量对n型氧化物超导体Nd_(1.85)Ce_(0.15)CuO_(4+δ)超导转变的影响  

INFLUENCE OF ANNEALING PROCESS AND OXYGEN CONTENT ON THE SUPERCONDUCTING TRANSITION OF Nd_(1.85)Ce_(0.15)CuO_(4+δ)

作　　者：靳常青[1] 吴冰青[1] 李建奇[1] 王文魁[1] 姚玉书[1] 

机构地区：[1]中国科学院物理研究所,北京100080

出　　处：《低温物理学报》1991年第3期169-175,共7页Low Temperature Physical Letters

基　　金：国家超导中心的资助

摘　　要：本文着重研究了 N_2气氛中不同温区退火及降温过程对 n 型氧化物超导体 Nd_(1.85) Cc_(0.15)·CuO_(4+δ)超导转变的影响,在样品的低温电阻测试中发现了一系列电阻降落台阶,表明 Nd_(1.85)·Cc_(0.15)CuO_(4+δ)除了目前已知的起始温度为25K 的超导转变之外,还可能存在其它的超导转变.热重实验表明,Nd_(1.85)Cc_(0.15)CuO(4+δ)在后处理过程中有几种不同的失氧过程,它们对样品超导转变的作用明显不同.X-射线衍射结果表明,具有不同电阻转变特性的样品,其结构无明显差别.SEM,EDAX 和 TEM 实验结果表明在 Ce 均匀掺杂的样品中形成不同超导转变的主要原因是 T'相晶格中氧含量及其有序化程度的差异.The effect of annealing process in N2 atomousphere on the superconducting transition of Nd1.85 Ce0.15 CuO4+δ has been investigated.Two drops of resistance in some samples was found,which means may exist other kind of superconducting transition from except for the well known transition with Tc about 25K so far,but no difference of structure was observed from the X-ray diffraction pattern for the above samples.The TG measurement showed two steps in the weight loss,which indicated that oxygen escaped from different position of the crystal lattic during the annealing process.The experiment of SEM,EDAX and TEM suggested that the oxygen content and it's order be responsible for the different superconducting transition.

关 键 词：后处理 氧 氧化物 超导体 超导转变 

分 类 号：TM262[一般工业技术—材料科学与工程]