Y-211与Y_2O_3掺杂的熔融织构YBCO的超导钉扎效应及微结构研究  

A comparitive study on the pinning effects and microstructure for melt-textured YBCO bulk with Y_2O_3 and Y_2BaCuO_5

作　　者：沙建军[1] 杨晓莉 郁刚[1] 

机构地区：[1]中国原子能科学研究院反应堆工程设计研究所,北京102413 [2]银川市第一职业中学,宁夏银川750001

出　　处：《宁夏大学学报（自然科学版）》2002年第4期330-334,共5页Journal of Ningxia University(Natural Science Edition)

摘　　要：采用顶部籽晶熔融织构法,结合Y_2O_3和Y-211掺杂制备了高质量的准单畴YBCO块材.Jc测量结果表明,对于Y_2O_3掺杂的YBCO块材,其临界电流密度Jc在10K温度和0.6T磁场下达到1.60×10~6A/cm^2,用合作钉扎理论可推得,其在70K温度和2T磁场下为1.24×10~4/cm^2。扫描电镜观察结果表明,掺杂Y_2O_3所形成的Y-211粒子是柱状的,而掺杂Y-211在母体材料中是球形的,其尺寸接近纳米粒子。掺杂Y_20_3比Y-211更能增强磁通钉扎效应并有效地改善样品的生长状况。Y-211粒子与超导母体材料之间的界面对磁通钉扎起主要作用,Y-211粒子作为强钉扎中心属于界面钉扎。By using the method of artificial doping Y-211 phase and Y2O3 powder for melt-textured growth (MTG) with a top-seeded technique to prepare the quasi-single crystal domain YBCO bulk materials. The Jc of specimens 1# reaches 1.6 ×106 A/cm2 under 0.6 T at 10 K, its Jc derived from the collective pinning theory is about 1.24×104 A/cm2 under 2T at 70 K. The SEM observation of specimens indicates that doping of Y2O3 powder is more effective than Y-211 particles in improving the growth quality of melt-textured YBCO superconductor and in reducing the microcrack of specimens. Doping the Y2O3 powder leads to columnar Y-211 particles, while doping the Y-211 particles directly to matrix materials leads to spherical Y-211 particles, combining with the microstructures, Jc measurements shows that the interfaces between the Y-211 particles and the Y-123 matrix are most important on flux bundle pinning, in which the gradient of free energy is lager than that of other places.

关 键 词：高温超导材料 熔融织构 YBCO 准单畴 超导钉扎效应 微结构 Y-211粒子 Y2O3 掺杂 临界电流密度 

分 类 号：O511[理学—低温物理]