热处理条件及Gd替代对Nd_(1.85)Ce_(0.15)CuO_(4-y)超导电性的影响  

THE EFFECT OF HEAT TREATMENT CONDITION AND Gd SUBSTITUTION ON Nd_(1.85)Ce_(0.15)CuO_(4-y)SUPERCONDUCTIVITY

作　　者：韩谷昌 王玉贵[1] 

机构地区：[1]中国科学院等离子体物理研究所,合肥230031

出　　处：《低温物理学报》1993年第3期228-233,共6页Low Temperature Physical Letters

摘　　要：本文研究了在各种气氛下退火及冷却速度对Nd_(1.85)Ce_(0.15)CUO_(4-y)超导体超导性能的影响。发现Nd_(1.85)Ce_(0.15)CUO_(4-y)超导体超导转变温度T_c不仅与退火时的气氛,而且与冷却速度和冷却环境密切相关。“原生长”(as-grown)样品亦具有大块超导电性,但其超导含量及T_c均较低,“原生长”样品N_2或H_2退火并快速淬火后,样品性能明显改善,其起始转变温度约20K,零电阻温度为17K。交流磁化率测量显示晶胞中的氧空位越多T_c和超导相含量也较高,氧空位的形成可以通过还原退火及快速淬火获得。Gd替代Nd的结果表明,随Gd含量增加,T_c下降,最后超导电性消失。The effect of various atmospheres and cooling rate on Nd1.85Ce0.15CuO4-y superconductivity was studied. Tt was found that the transition temperature of Nd1.85Ce0.15CuO4-y superconductors was determined not only by reduction atmosphere, but also by cooling rate and cooling condition. As-grown samples were found to be superconducting even though their critical temperature and superconducting content is relatively low. After as-grown sample was annealed and subsequently quenched in flowing N2or H2, the superconducting nature of the sample was obviously improved. Its Tconset is 20K, Tco= 17K. The result from a. c. magnetic susceptibility shows that the Tc and superconducting proportion are raised with the increase of oxygen deficiency. Oxygen deficiency was formed during the reduction heat treatment and rapid quenching to the room temperature. The result of the Gd substitution for Nd displays that the Tc reduced as the amount of Gd substitution was increased, and finally its superconductivity disappeared.

关 键 词：超导体 超导性 热处理 钆 NCCO 

分 类 号：O511.2[理学—低温物理]