混合物理化学气相沉积法制备MgB_2单晶纳米晶片的研究  

Study on single crystal MgB_2 nanosheets grown by hybrid physical-chemical vapor deposition

作　　者：张焱[1] 王越[1] 马平[1] 冯庆荣[1] 

机构地区：[1]北京大学物理学院应用超导研究中心,人工微结构与介观物理国家重点实验室,北京100871

出　　处：《物理学报》2014年第23期320-327,共8页Acta Physica Sinica

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

摘　　要：利用混合物理化学气相沉积法在石墨衬底上制备出了晶形为六角结构、厚度不同、径向尺寸不一的Mg B2单晶纳米晶片.利用纳米定向转移技术将此晶片转移到了碳支持膜铜网上,以便对其精细结构等物性进行表征.电输运测量和磁性测量结果都表明晶片具有超导电性:T c onset=38K,T c(0)=33K.扫描电子显微镜图像表明,晶片表面平整、厚度分布在几个纳米到200 nm之间,宽度从几微米到上百微米;高分辨透射电镜图像显示出晶片具有周期性晶格条纹.选区电子衍射数据与Mg B2已有的单晶衍射数据相符.这些测量结果证实了其确为高质量单晶Mg B2超导纳米晶片.本文不仅提出了一种全新的制备单晶Mg B2的方法,也观察到了纳米尺度Mg B2单晶的零电阻现象,为后续的磁通钉扎、纳米力学性能等领域的深入研究提供了合适的素材.This report is focused on the Mg B2 nanosheets which have a hexagonal single crystal structure with variable thickness and different radial dimensions. The nanosheets are fabricated by hybird physical-chemical vapor deposition for the first time, as far as we know, and meanwhile they can be site-specific transferred so as to make physical properties measurement. Results of electrical and magnetic measurements indicate that the nanosheets is superconductive with a Tconset= 38 K, Tc（0） = 33 K. The images of scanning electrical microscope show that the nanosheets have a nanoscale thickness and have not only a large scale in wildth from several microns to hundreds of microns but also a flat cleaning surface. The selected area electrical diffraction data is consistent with the early report of Mg B2 diffraction. According to those results, the single crystal nanosheets with high quality can be surely indentified as Mg B2. It suggests a new technique for Mg B2 single crystal fabrication, and a zero electrical behavior is observed in nanoscale single crystal Mg B2.This could be a new opportunity to make a right material for the afterward research such as flux vortices, nanoscale mechanical properties.

关 键 词：单晶Mg B2 超导纳米晶片 零电阻 混合物理化学气相沉积法 

分 类 号：TB383.1[一般工业技术—材料科学与工程]