NdBa_2Cu_3O_(7-δ)/YBa_2Cu_3O_(7-δ)多层膜体系的外延结构和磁通钉扎的研究  

On epitaxial structure and flux pinning of NdBa_2Cu_3O_(7-δ)/YBa_2Cu_3O_(7-δ) superconducting multilayers

作　　者：陈昌兆[1] 蔡传兵[1] 刘志勇[1] 应利良[1] 高波[1] 刘金磊[1] 鲁玉明[1] 

机构地区：[1]上海大学物理系,上海200444

出　　处：《物理学报》2008年第7期4371-4378,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50672057;10774098);上海市重点科技攻关项目(批准号:055211003);中德合作科研项目(批准号:[2006]3139);上海市浦江人才计划(批准号:5PJ14048);上海市重点学科建设项目(批准号:T0104)资助的课题~~

摘　　要：采用脉冲激光沉积技术,在单晶SrTiO3基底上外延生长了一系列名义结构为p×(NdBa2Cu3O7-δ(m)/YBa2Cu3O7-δ(n))的多层膜和准多层膜(单元层NdBa2Cu3O7-δ较厚而YBa2Cu3O7-δ呈非连贯的岛状分布,m,n为激光脉冲数,p为重复周期).样品的超导转变温度在87—91K范围,具体大小取决于不同的调制结构,多层膜的重复周期越大,层状界面越多,超导转变温度就越低.磁传输测量表明,准多层的样品不仅具有较高的超导转变温度,而且具有较强的磁通钉扎性能,77K零场下的临界电流密度高达4×106A/cm2,显示出良好的应用前景.By using pulsed-laser deposition technique, a series of multilayers of NdBa2Cu3O7-δ/YBa2Cu3O7-δ, namely with the structures of p × [ NdBa2Cu3O7-δ （ m）/YBa2Cu3O7-δ （n） ], are prepared on single-crystal SrTiO3, where m and n denotes the number of laser pulses and p is the number of repetetions. XRD patterns indicate that all samples are highly c-axis oriented, and the superconducting transition temperatures of these samples are in the range of 87-91 K, depending on different modulating structures. The larger the modulation period p and consequently the more the interracial surfaces, the lower the superconducting transition temperature. Magneto-transport measurements reveal that the quasi-muhilayers such as NY3 [40 × （75/5） ] （island- like YBa2 Cu3 O7-δ distributed in NdBa2 Cu3O7-δ films） exhibit not only the highest Tc, but also the best magnetic properties. The critical current density of such a quasi-muhilayers can be as high as 4 × 10^6 A/cm^2 under self fields, showing the promising potential application for coated conductors.

关 键 词：NdBa2Cu3O7-δ 多层膜 磁通钉扎 临界电流密度 

分 类 号：TN249[电子电信—物理电子学]