采用扩散法制备高临界电流密度的MgB_2块材研究  

HIGH CRITICAL CURRENT DENSITY OF MgB_2 BULKS SYNTHESIZED BY AN LMPROVED Mg-DIFFUSION METHOD

作　　者：潘熙锋[1] 杨烨[1] 赵勇[1] 

机构地区：[1]西南交通大学超导研究开发中心

出　　处：《低温物理学报》2007年第4期270-274,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金项目(项目编号:50372052;50588201);国家重大基础研究项目(973)(项目编号:2007CB616906)资助的课题~~

摘　　要：采用一种新的Mg扩散方法,在常压下成功制备出致密的MgB2超导块材,样品密度最高达1.95g/cm3,并得到了最佳的热处理条件.采用X射线衍射仪(XRD),扫描电镜(SEM)和超导量子干涉仪(MPMS)分别对样品的物相,微观结构和超导性能进行了表征.结果表明:纯的MgB2在5×10-3T的外场下,起始超导转变温度(Tc)为38.1K,转变宽度仅0.9K;10K自场下临界电流密度(Jc)值达0.53MA/cm2.此外,纳米Pr6O11或C掺杂能显著改善MgB2的实用化性能,其中15at.%C掺杂的MgB2(MgB1.85C0.15)在10K,6T下,Jc高达104A/cm2.An improved Mg-diffusion method has been successfully utilized to prepare the MgB2 bulks with a highest density of 1.95 g/cm^3 under the normal pressure, and the optimal heat treatment conditions have been attained. The crystal structure, microstructure and superconductivity were investigated by X-ray diffraction, scanning electron microscope （SEM） and magnetic properties measurement system （MPMS）, respectively. The results show that the Tc and △Tc for pure MgB2 are 38.1K and 0.9K under 5 × 10^-3T, and the Jc reaches 0.53 MA/cm^2 at 10K and self-field. Furthermore, the nano-Pr6O11 （or C） doping can significantly improve the applied properties of MgB2. Among them at 10 K and 6 T, the Jc for MgB1.85C0.15 reaches 10^4 A,/cm^2.

关 键 词：MGB2 扩散法 临界电流密度 磁通钉扎 

分 类 号：O511.3[一般工业技术—材料科学与工程]