Fishtail phenomenon in Ho-added PMP YBCO

作     者：J.G.Wen N.Koshizuka 

作者机构：Northwest Institute for Nonferrous Metal Research Xi’an China Superconductivity Research Laboratory ISTEC 10-13 Shinonome 1-chome Koto-ku Tokyo Japan CCAST World Laboratory Beijing China Structure Research Laboratory University of Science and Technology of China Hefei China 

出 版 物：《Chinese Science Bulletin》 (科学通报(英文版))

年 卷 期：1998年第43卷第21期

页      面：1842-1846页

核心收录：

学科分类：080705[工学-制冷及低温工程] 07[理学] 070205[理学-凝聚态物理] 08[工学] 0807[工学-动力工程及工程热物理] 0702[理学-物理学] 

主　　题：flux pinning fishtail effect element substitutions critical current density. 

摘      要：The Y 1-xHo xBa-2Cu-3O y superconductors were fabricated by the powder melting process (PMP) method and the magnetic hysteresis loops of these samples were measured at different temperatures by a SQUID magnetometer (up to 7 T). Critical current density was calculated by the Bean critical state model. The results indicate that the fishtail effect is observed in Y 0.6Ho 0.4Ba-2Cu-3O y below 60 K, while no fishtail can be found in Y 0.8Ho 0.2Ba-2Cu-3O y until 30 K. The peak field at which J c reaches its maximum decreases with the increasing magnetic field. In the Y 0.6Ho 0.4Ba-2Cu-3O y sample, the fishtail effect disappears when the temperature is raised to 77 K. In addition, after the Y 0.6Ho 0.4Ba-2Cu-3O y sample was re-sintered at high temperature for a long time, the fishtail can be found in two field directions (H∥C and H⊥C). It is considered that the paramagnetism in the sample may be responsible for the fishtail effect in Ho-added YBCO. Also, the cation disorder created by Ho addition may be another reason for the fishtail.