SUPERCONDUCTIVITY AND CRYSTALLOGRAPHIC PROPERTIES OF LA2-XNAXCUO4-DELTA, LA-2-X-KCUO4-DELTA

被引:16
作者
SHIBATA, H
KINOSHITA, K
YAMADA, T
机构
[1] NTT Basic Research Laboratories, Musashino-shi, Tokyo
来源
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS | 1990年 / 170卷 / 5-6期
关键词
Ceramic Materials - Crystallography - Lanthanum Compounds--Electric Conductivity;
D O I
10.1016/0921-4534(90)90008-3
中图分类号
O59 [应用物理学];
学科分类号
摘要
Superconductivity and crystallographic properties of La2 - xMxCuO4 - δ (M = Na, K) are studied. In the La2 - xMxCuO4 - δ system, superconductivity is detected for x ≥ 0.2. Oxygen content analysis shows that the system has more oxygen vacancies than the La2 - xSrxCuO4 - δ system. These oxygen vacancies may reduce the hole concentration, and high Na-doping is needed to produce superconductivity. In the La2 - xKxCuO4 - δ system, superconductivity is observed for the first time. Resistivity and magnetic susceptibility measurements show that Tc(onset) is 40 K and the Meissner volume fraction is about 4% for x = 0.7. The system changes from orthorhombic to a tetragonal K2NiF4 structure at x ≈ 0.3 and only tetragonal samples show superconductivity. © 1990.
引用
收藏
页码:411 / 415
页数:5
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