Mg/B化学计量比对MgB_2超导电性和磁通钉扎性能的影响  

Influence of Different Mg/B Stoichiometry on Superconductivity and Flux Pinning Properties of MgB_2 Bulks

作　　者：李飞[1] 潘熙锋[1] C.H.Cheng 周杰俤[1] 杨烨[1] 赵勇[1,2] 

机构地区：[1]西南交通大学磁浮技术与磁浮列车教育部重点实验室,四川成都610031 [2]University of New South Wales, Sydney 2052 NSW, Australia

出　　处：《稀有金属材料与工程》2011年第5期863-866,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50588201,50872116);高等学校博士学科点专项科研基金(200806130023);国家重大基础研究“973”项目(2007CB616906)

摘　　要：采用固相反应法制备一系列的MgxB2(x=0.90,0.95,1.0,1.05,1.10)超导块材,并详细研究不同Mg/B化学计量比对MgB_2超导性能的影响。采用X射线衍射(XRD)仪,扫描电镜(SEM)和超导量子干涉(MPMS)仪分别对样品的物相、微观结构和超导性能进行表征。结果表明:名义组分为Mg_(0.9)5B_2的样品临界电流密度Jc性能最好。由于Mg的不足,抑制了晶粒生长,同时也使得MgB_2内部Mg缺位、△Tc、FWHM、H_(c2)和H_(irr)明显增加,显著改善MgB_2的磁通钉扎性能。A series of MgxB2（x=0.9,0.95,1.0,1.05,1.10） bulks samples were prepared by the in-situ solid-state reaction method,and then the effects of Mg/B stoichiometry on superconductivity and flux pinning properties of MgB2 were discussed.Phase purity,microstructure and superconducting properties were characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM） and magnetic properties measurement system（MPMS）,respectively.The results show that the sample with a nominal composition,Mg0.95B2 has the highest Jc value among all the samples.In the Mg-deficient MgB2,the degraded grains grow and lack of Mg sites are responsible to significant enhancement of the Hirr and Hc2 and the enlarged △Tc and FWHM,resulting in the great improvement of flux pinning properties of MgB2.

关 键 词：MGB2 临界电流密度 磁通钉扎 

分 类 号：TM26[一般工业技术—材料科学与工程]