MgB2超导膜的厚度与其Jc(5K，0T)的关系  

Thickness dependence of critical current density in MgB_2 films fabricated by hybrid physical-chemical vapor deposition

作　　者：陈艺灵[1] 张辰[1] 何法[2] 王达[1] 王越[1] 冯庆荣[1] 

机构地区：[1]北京大学物理学院,北京大学人工微结构与介观国家重点实验室,北京大学应用超导研究中心,北京100871 [2]北京大学重离子物理研究所,北京100871

出　　处：《物理学报》2013年第19期446-452,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划973(批准号:2006CD601004,2011CB605904,2011CBA00104);国家自然科学基金(批准号51177160,11074008);国家基础科学人才培养基金(批准号:J0630311)资助的课题~~

摘　　要：通过混合物理化学气相沉积法(hybrid physical-chemical vapor deposition,HPCVD),在(000l)SiC衬底上制得一系列从10 nm到8μm的MgB2超导膜样品,并对它们的形貌、超导转变温度Tc和临界电流密度Jc与膜厚度的关系进行了研究.观察到Tc随膜厚度增加上升到最大值后,尽管膜继续增厚,但Tc值保持近乎平稳,而Jc则先随膜厚度增加上升到最高值后,继而则随膜的厚度的增加而下降.MgB2膜的Tc(0)和Tc(onset)值与膜厚的关系基本一致,Tc(0)在膜厚为230 nm处达到最大值Tc(0)=41.4 K,而Jc(5K,0T)在膜厚为100 nm时达到最大值,Jc(5 K,0 T)=2.3×108A·cm-2,这也说明了我们能用HPCVD方法制备出高质量干净MgB2超导膜.本文研究的超导膜厚度变化跨度非常大,从10 nm级的超薄膜到100 nm级的薄膜,再到几微米的厚膜,如此Tc和Jc对膜厚度变化的依赖就有了较完整、成体系的研究.并且本文的工作对MgB2超导薄膜制备的厚度选取具有实际应用意义.MgB2 superconducting films with a thickness of 10 nm to 8 μm have been prepared on SiC substrates by hybrid physical-chemical vapor deposition （HPCVD）. The study on Tc and Jc shows that as the film grows thicker, Tc increases and then keeps stable, which Jc increases at first, and then drops dramatically. We get the maximum Tc at 41.4 K and Jc at 2.3 × 10^8 A·cm^-2. This also shows that we can use the method of HPCVD to prepare high-quality of clean MgB2 film. And its thickness can be from 10nm ultrathin films and 100 nm thin films up to 8 μm thick film. It is the first time so far as we know that Tc and Jc are studied in this range of thickness. This will lead to a complete and systematical understanding of the superconducting MgB2 films. And it is also important and practical to choose the thickness when preparing MgB2 films.

关 键 词：MgB2超导膜 混合物理化学气相沉积法 厚度 临界电流密度 

分 类 号：TM26[一般工业技术—材料科学与工程]