摘要
本工作在空气中成功地制备了直径为32 mm、厚度为13 mm的高性能、大尺寸GdBa_(2)Cu_(3)O_(7-δ)(GdBCO)单畴超导块材。以YBa_(2)Cu_(3)O_(7-δ)(Y123)作为液相源可以有效地避免生长过程中液相源的扩散流失,并有利于GdBCO超导块材的性能提升。通过研究该超导块材的超导性能和微观结构发现,整个样品的超导转变温度保持在94 K以上,最大捕获磁场(B_(trap))可以达到0.29 T。在77 K的温度及自场条件下,由于Gd_(2)BaCuO_(5)(Gd211)粒子的富集,在距样品表面较远的边缘位置的B2样品中获得最大临界电流密度,其值可达5.29×10^(4)A/cm^(2)。在离超导块材表面较近的区域,液相源的不足使得该区域的钉扎中心主要由氧缺陷来提供,而氧缺陷形成的磁通钉扎中心在籽晶下方聚集,并且其扩散速率会随着氧缺陷与籽晶间距离的增加而减小,这提高了籽晶下方位置的C1样品的临界电流密度,使之高于边缘位置的B1样品的临界电流密度。而在离超导块材表面稍远的区域,充足的液相源使该区域的钉扎中心主要由Gd211粒子来提供,而籽晶下方位置的C2样品和边缘位置的B2样品的临界电流密度相差不大,这是由于在离块材表面稍远的区域都存在大量的Gd211粒子作为磁通钉扎中心;并且由于Gd^(3+)对Ba^(2+)的替代,两者的临界电流密度在中高场下都有一定的提高,这对超导块材的应用非常重要。
Alarge-sized GdBa_(2)Cu_(3)O_(7-δ)(GdBCO)bulk superconductor with high performance,which is 32 mm in diameter and 13 mm in thickness,has been successfully fabricated by the top-hot-seeded melt-texture growth process in air.The YBa_(2)Cu_(3)O_(7-δ)(Y123)is chosen as the liquid phase source,which can effectively avoid the leakage of the liquid phase during the crystal growth,ultimately leading to the performance improvement of the GdBCO bulk superconductor.Both superconducting properties and microstructure of the bulk have been investigated.It can be found that the superconducting transition temperature(T_(C))keeps above 94 K,and the maximum trapped magnetic flux density(B_(trap))of the bulk is 0.29 T.The highest critical current density(J_(C))of 5.29×10^(4)A/cm^(2)is obtained in the B2 specimen near the edge far from the surface of the bulk at 77 K in self field,which can be explained by the enrichment of the Gd_(2)BaCuO_(5)(Gd211)particles.In the region close to the surface of the bulk,the pinning centers are mainly provided by the oxygen vacancies due to the insufficient liquid phase source.These oxygen vacancies highly aggregate under the seed and its diffusion rate decreases with the increase of the distance from the center during crystal growth,which results in a higher J_(C)of the C1 specimen under the seed than J_(C)of the B1 specimen near the edge.In comparison,in the region far from the surface of the bulk,the pinning centers are mainly provided by the Gd_(2)BaCuO_(5)(Gd211)particles due to the sufficient liquid phase source.Owing to a large number of Gd211 particles as the effective pinning centers in the whole region far from the surface of the bulk,the J_(C)of the C2 specimen under the seed is close to that of the B2 specimen near the edge.Moreover,the J_(C)of both C2 and B2 specimens have been improved in intermediate and high fields because of the substitution of Ba^(2+)by Gd^(3+),which is vitally important for the engineering applications of the bulk superconductors.
作者
张嘉颖
袁玖玮
张玉凤
娄紫微
周文礼
张晓娟
彭麟
徐燕
徐建明
杨瑰婷
和泉充
ZHANG Jiaying;YUAN Jiuwei;ZHANG Yufeng;LOU Ziwei;ZHOU Wenli;ZHANG Xiaojuan;PENG Lin;XU Yan;XU Jianming;YANG Guiting;IZUMI Mitsuru(College of Mathematics and Physics,Shanghai University of Electric Power,Shanghai 201306,China;State Key Laboratory of Space Power Technology,Shanghai Institute of Space Power-Sources,Shanghai 200245,China;Laboratory of Applied Physics,Tokyo University of Marine Science and Technology,Tokyo 135-8533,Japan)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第15期9-14,共6页
Materials Reports
基金
国家自然科学基金(11004129)
留学回国人员科研启动基金(SRF for ROCS,SEM)
上海市教育委员会科研创新项目(11YZ197,12ZZ174)
上海市自然科学基金(16ZR1422700)
上海电力大学通识教育课程建设项目(20182203)。
关键词
单畴GdBCO超导块材
顶部热籽晶熔融织构生长法
捕获磁通密度
临界电流密度
single-domain GdBCO bulk superconductor
top-hot-seeded melt-texture growth process
trapped magnetic flux density
critical current density
