Y_(1-x)Pr_xBa_2Cu_3O_(7-δ)体系中的离子价键特性与超导电性  

BOND VALENCE CHARACTER AND SUPERCONDUCTIVITY IN Y_(1-x)Pr_xBa_2Cu_3O_(7-5) SYSTEM

作　　者：张小俊[1] 王劲松[1] 许祝安[1] 张其瑞[1] 

机构地区：[1]浙江大学物理系,杭州310027

出　　处：《物理学报》1993年第12期1985-1989,共5页Acta Physica Sinica

摘　　要：基于中子散射实验结果,应用键价计算方法研究了Y_(1-x)Pr_xBa_2Cu_3O_(7-δ)(x=0,0.2,0.4,0.6)体系中离子的价键特性。对Cu(1),Cu(2)及Y(Pr)的键价和计算结果表明,Cu(2)的键价和与超导临界温度(T_c)之间存在着强烈的关朕。在氧含量基本保持不变的情况下,随Pr含量的增加,体系中电荷分布发生改变,Cu(1),Cu(2)的键价和下降,Y(Pr)的键价和上升,CuO_2面内的空穴部分地被局域于Pr-o键上。Pr对超导电性的淬灭,主要应归结为Pr对CuO_2面内空穴的局域化作用。Based on data of neutron diffraction measurements, the oxidation states in Y1_xPrxIBa2Cu2O7_δ system are determined by bond valence sums (BVS) calculation. It is found that a close correlation between the BVS value of Cu(2) and superconducting critical temperature (Tc) exists. We believe that the increase of Pr content leads to the variation of charge distribution when the content of oxygen remains almost constant. At the same time ,the BVS value of Cu(l) and Cu(2) decreases,while that of Y(Pr) increases,and the holes in CuO2 plane are partly localized in Pr桹 bond. The quenching of superconductivity by Pr ions is mainly attributed to this localization of the holes in CuO2 plane by Pr ions.

关 键 词：超导体 化学键 键价 临界温度 

分 类 号：O511.2[理学—低温物理]