IRREVERSIBLE BEHAVIOR OF ORIENTED GRAINED YBA2CU3OX .2. RELAXATION PHENOMENA

被引：35
作者：
KELLER, C
KUPFER, H
MEIERHIRMER, R
WIECH, U
SELVAMANICKAM, V
SALAMA, K
机构：
[1] UNIV HOUSTON,TEXAS CTR SUPERCOND,DEPT MECH ENGN,HOUSTON,TX 77004
[2] UNIV KARLSRUHE,W-7500 KARLSRUHE 1,GERMANY
来源：
CRYOGENICS | 1990年 / 30卷 / 05期
关键词：
critical currents; relaxation phenomena; YBaCuO compounds;
D O I：
10.1016/0011-2275(90)90167-B
中图分类号：
O414.1 [热力学];
学科分类号：
摘要：
Relaxation phenomena of oriented grained YBa2Cu3Ox bulk material were investigated by vibrating sample magnetometry and inductive flux profile measurements. The applied magnetic field was directed parallel and perpendicular to the a - b plane. Since the agreement of shielding and transport critical currents presented in Part 1 ruled out granularity, experimental data could by analysed in terms of thermally activated flux creep. A survey of the theory of flux creep is given with special emphasis on the relationship between voltage versus current characteristics and time dependent decay of the magnetic moment. Temperature and field dependent activation energies were determined. Sweep rate dependent measurements of d.c. magnetization and a.c. flux profiles allowed access to short time relaxation phenomena. The time dependent decay of the critical current was found to deviate from the In t behaviour on this time scale. © 1990.
引用
收藏
页码：410 / 416
页数：7
相关论文
共 29 条
123