Detailed analysis of magnetic phase diagram in Bi-2223 superconductors

Magnetic properties of a high-quality Bi-2223 superconducting tape have bee n studied by various magnetization measurements using SQUID magnetometer fo r understanding the flux dynamics. The remnant flux relaxation was carried out for a very long time period of up to 24 h. The curve of the magnetizati on with In(t) can be divided into two relaxation rates in different periods of time at higher held. A phase transition boundary of temperature and mag netic field, in which the held has two different relaxation rates, is descr ibed in a three- to two-dimensional decoupling transition. (C) 2000 Elsevie r Science B.V. All rights reserved.