Ca掺杂Bi-Sr-Cu-O体系的调制结构和超导电性研究  

Study on modulation structure and superconductivity of Bi-Sr-Cu-O system doped with Ca

作　　者：孙本哲[1] 周思朗[1] 王恒[1] 祁阳[1] 

机构地区：[1]东北大学理学院,材料物理与化学研究所,辽宁沈阳110819

出　　处：《功能材料》2013年第21期3130-3134,共5页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51172040);中央高校基本科研基金资助项目(90405002)

摘　　要：采用溶胶-凝胶方法合成了名义组分为Bi2Sr2-x Cax CuO6+δ(x=0.1、0.3、0.5、0.7和0.9)的系列样品,运用XRD、TEM和四引线法,研究了钙掺杂对Bi-2201相晶体结构、点阵参数、非公度调制结构和超导临界转变开始温度(TC,onset)的影响。研究发现,钙原子已进入到Bi-2201单胞内部,在整个掺杂体系内,Bi-2201单胞都能够维持正交点阵;随着钙掺杂量增加,正交单胞的c轴长度逐渐减小,而当x>0.3时,Bi-2201相调制波矢的b轴分量逐渐减小,而c轴分量有所上升;电阻随温度变化曲线表明,当x=0.3时,TC,onset达到最高,之后有所下降,这与调制波矢在b轴分量的变化相一致,这种变化能够用晶格失配模型很好地解释。A series of samples with the nominal composition of Bi2 Sr2-x Ca2 CuO6＋δ （x =0.1,0. 3,0. 5,0. 7,0. 9） were prepared by sol-gel method. By means of XRD, TEM and standard four-probe technique, it was investiga- ted that the effects of Ca doping on lattice types and parameters of Bi-2201 phase, the incommensurate modula- tion structure and the onset temperature of superconducting critical transition （Tc ）. It was found that Bi- 2201 phase with orthorhombic symmetry can be maintained with the introduction of Ca^2＋ in the whole doping range. With increasing x, lattice parameter c was decreasing gradually. When x〉0.3, the b^＊ component of the modulation wave vector was decreasing while the c ^＊ component was increasing with increasing x. Experi- mental R-T curves show that Tc was the highest when x = 0.3, and then has a declining trend with increas- ing x, which was in agreement with the variation of the b ^＊ component of the modulation wave vector and can be interpreted by the crystal misfit model.

关 键 词：掺杂 非公度调制结构 超导临界转变开始温度 调制波矢 晶格失配 

分 类 号：O766[理学—晶体学]