Y_1Ba_2Cu_3O_(7-δ)的氧离子缺位数,氧空穴数变化与结构相变的关系  

RELATION BETWEEN THE CHANGE OF OXYGEN DEFICIENCY AND OXYGEN HOLE AND THE TRANSITION OF STRUCTURE FOR Y_1Ba_2Cu_3O_(7-δ)

作　　者：苏文辉[1] 靳常青[1] 何岚鹰[1] 王一峰[1] 刘宏建[1] 龙骧[2] 高忠民[2] 

机构地区：[1]吉林大学固体物理教研室 [2]吉林大学分析测试中心

出　　处：《低温物理学报》1990年第3期230-236,共7页Low Temperature Physical Letters

基　　金：国家自然科学基金;国家教委博士点基金

摘　　要：在空气、氮气、真空(10^(-3)乇)、氧气等气氛条件下,利用高温 X 射线动态跟踪法和 TG-DTA测定了 Y_1Ba_4Cu_3O_(7-δ)的结构和氧缺位量随温度的变化,注意到不同气氛对超导体中晶格氧和吸附氧的动态平衡的影响;测得氧缺位量δ与晶体结构转变之间的关系.根据文献[11]关于Cu-O 间电子转移的结论,计算出 Cu-O_2层中 O 的平均空穴数 n_h 与结构变化的对应关系.O≤δ≤0.25,0.25≥n_h≥0.125为正交超导相的稳定区,氧的空穴浓度为(1.44—0.72)x10^(21)/cm^30.25≤δ<0.5,0.125≥n_k>0为正交、四方相的转变过渡区;0.5≤δ≤1,n_h=0为四方非超导相的稳定区.因此,除了四方非超导结构区氧负离子取2价外,其它情况氧负离子也不总是取负2价.The changes of structure and oxygen deficiency of Y1Ba2Cu3O7-δas a function of temperature have been studied by kinetical high temperature X-ray diffraction in air,nitrogen,oxygen and vaccum (10-3 torr).The influence of different atmosphere on the equilibrium between lattice oxygen and absorbed oxygen was considered.The relation of oxygen deficiency and structure transition has been studied.According to the conclusion about the electron transfer between Cu and C[11],the relation between the average oxygen hole nh in Cu-O layer and the structure transition was found.0≤δ≤0.25,0.25≥nh ≥0.125 is the stable region of superconducting orthorho-mbic phase.The density of oxygen hole is approximately (1.44-0.72)×1021/cm3,0.25≤δ<0.5,1.25≥nh>0,the transition region of O(orthorhombic) T(tet ragonal);0.5≤δ≤1,nh=0,the stable region of non-superconducting tetragonal phase.Therefore,the negtive 2 valence will not always be taken for oxygen aricns except for non-superconducting tetragonal phase.

关 键 词：超导体 氧化物 氧 缺位数 空穴数 

分 类 号：TM262[一般工业技术—材料科学与工程]