Pr掺杂对Y_(1-x)Pr_xBa_2Cu_3O_(7-δ)体系的自旋能隙的影响  

THE INFLUENCE OF Pr DOPING ON THE SPIN GAP IN Y 1- x Pr x Ba 2Cu 3O 7- δ

作　　者：赵芸[1,2] 罗培勋[1,2] 孙学峰[1,2] 赵霞 范晓娟[1,2] 李晓光 

机构地区：[1]中国科学技术大学材料科学与工程系 [2]安徽机电学院基础部

出　　处：《低温物理学报》1998年第2期94-98,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金

摘　　要：Ｙ１－ｘＰｒｘＢａ２Ｃｕ３Ｏ７－δ系列样品，在ｘ＝０时，Ｔｃ～９０Ｋ，电阻率ρ随温度线性变化，ｘ＝０．１，０．３，０．４，０．４５时，电阻率ρ分别在１４０Ｋ，１７５Ｋ，１８５Ｋ，１９５Ｋ以下温区，向下偏离了线性，出现自旋能隙打开现象．自旋能隙打开温度Ｔ＊随掺Ｐｒ量ｘ的增加而增大，而超导转变温度Ｔｃ则减小，且Ｔ＊和Ｔｃ随ｘ呈近似线性变化．这与ＮａｏｔｏＮａｇａｏｓａ和ＰａｔｒｉｃｋＡ．Ｌｅｅ提出的由具有自旋能隙是高温超导体自旋和电荷分离模型特征所得的结果定性相一致．高于＋３价Ｐｒ的Ｙ位替代，及Ｐｒ、Ｙ离子半径的不匹配所造成的晶体微结构的变化，会使载流子浓度降低，从而表现出Ｐｒ的掺入对Ｔｃ起抑制作用．Abstract Among the Y 1- x Pr x Ba 2Cu 3O 7- δ samples, for x =0, T c ≈90K sample, the resistivity ρ changes linearly with the temperature; for x =0.1, 0.3, 0.4, 0.45, ρ deviates from the linear T dependence below 140K, 175K, 185K, 195K, respectively, which shows the opening of a spin gap. The spin gap opening temperature T * increases with the increasing of Pr doping x , otherwise the superconducting transition temperature T c decreases. Both T * and T c exhibit a nearly linear dependence with x . The phenomenon is corresponding with the theoretical prediction by Naoto Nagaosa and Patrick A. Lee. The over +3 valence Pr ion substitutes for Y ion, as well as the mismatching of Pr with Y ionic radius cause the change of microstructure, decrease the carrier density and show the depression on T c .

关 键 词：YPBCO 超导体 镨掺杂 自旋能隙 高TC 

分 类 号：TM262.014[一般工业技术—材料科学与工程] O511.1[电气工程—电工理论与新技术]