Irreversibility Field of Bi-2223 Silver-Sheathed Tape

                  Determined with Different Electric Field Criteria



M. Fukuda___________1), T. Kodama1), G. Morita1), E. S. Otabe1), T. Matsushita1*
 *);2), K. Itoh3)
1)Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Japan

2)Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

3)National Research Institute for Metals,1-2-1 Sengen, Tsukuba 305-0047, Japan



  The determination of the irreversibility field (Bi) is strongly influenced by*
 * both the electric

field criterion (Ec) for the determination of the critical current dencity (Jc)*
 * and the criterion of

Jc ( Jc).  Hence, it is needed to describe Bi as a function of Ec and  Jc.  In *
 *this study, we

observed Biwith various measurements on a Bi-2223 silver-sheathed tape wire: (1*
 *) imaginary ac

susceptibility, (2) current-voltage characteristic using a four probe method, (*
 *3) dc magnetization

hysterisis and (4) current-voltage characteristic estimated from the relaxation*
 * of magnetization.

In (2)-(4),  Jc = 1 x 107 A=m2  was used. Ec was varied from 10-2 V=m  to 10-10*
 * V=m  in the

measurements of (1)-(4). The vortex glass-liquid transition field (Bg) was also*
 * determined for the

two current-voltage characteristic measurements in the low and high electric fi*
 *eld regions.  It is

seen that Bibecomes higher when Ec is set higher. It is also found that Bg depe*
 *nds on the range

of electric field in which Bg is determined. This dependence is incompatible wi*
 *th the prediction

of the vortex glass-liquid transition theory.


Mr. Mitsuhiro Fukuda

c/o Professor T. Matsushita

Department of Computer Science and Electronics

Kyushu Institute of Technology

680-4 Kawazu, Iizuka 820-8502, Japan



tel&fax: +81-948-29-7683

e-mail:fukuda@aquarius10.cse.kyutech.ac.jp