[en] We have investigated the superconducting properties of bulk melt-processed YBCO using different experimental techniques. First, single domain materials (i.e. containing no grain boundaries) have been studied. Electrical resistivity, current-voltage characteristics, M-H loops, and A,C. susceptibility. have been measured for different field and current directions. The intragranular properties are characteristic of high-quality melt-processed YBCO material,,vith a critical current density J(c)(T=77K, B=1T//c) > 10(4) A/cm(2). The anisotropy ratio J(c)(ab)/ J(c)(c) is found to be close to 3. Both magnetic and transport measurements show that defects in the microstructure do not significantly impede the current flow inside the single domain. These results were compared to those measured on samples containing one "natural" single grain boundary which sometimes appears during the grain growth process. The intergranular properties show a much stronger current and magnetic field dependence than that measured within the grain and these differences are discussed.
Research center :
SUPRATECS - Services Universitaires pour la Recherche et les Applications Technologiques de Matériaux Électro-Céramiques, Composites, Supraconducteurs - ULiège
Disciplines :
Electrical & electronics engineering Physics
Author, co-author :
Vanderbemden, Philippe ; Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Capteurs et systèmes de mesures électriques
Cloots, Rudi ; Université de Liège - ULiège > Département de chimie (sciences) > Chimie inorganique structurale - Doyen de la Faculté des Sciences
Ausloos, Marcel ; Université de Liège - ULiège > Département de physique > Physique statistique appliquée et des matériaux - S.U.P.R.A.S.
Doyle, R. A.
Bradley, A. D.
Lo, W.
Cardwell, D. A.
Campbell, A. M.
Language :
English
Title :
Intragranular and intergranular superconducting properties of bulk melt-textured YBCO
A. M. Campbell and D. A. Cardwell, Bulk high temperature superconductors for magnet applications Cryogenics, vol. 37, pp. 567-575,1997.
D. Dimos, P. Chaudhari, J. Mannhart, and F. K. LeGoues, Orientation dependence of grain boundary critical current in YBa2Cu307.6 crystals Phys. Rev. Lett. vol. 61, pp. 219-222, 1988.
M. B. Field, D. C. Larbalestier, A. Parikh, and K.. Salama, Critical current properties and the nature of the electromagnetic coupling in melt textured YBa2Cu3064.JC bicrystals of general misorientation Physica C, vol. 280, pp. 221-233,1997.
D. J. Miller et al. Microstructure and transport behavior of grain boundaries in YBa2Cu3O : A comparison between thin films and bulk bicrystals Mat. Sei. Engineering, vol. B53, pp. 125-131, 1998.
C. Sarma et al. Measurement of current voltage characteristics of single grain boundaries in melt textured bulk YBajC O, Appl. Phys. Lett. vol. 64, pp. 109-111,1994.
W. Lo et al. Controlled processing and properties of large Pt-doped Y-Ba-Cu-0 pseudocrystals for electromagnetic applications J. Mater. Res. vol. 12, pp. 2889-2900,1997.
Ph. Vanderbemden, Design of an A.C. susceptometer based on a cryocooler Cryogenics, vol. 38, pp. 839-842, 1998.
L. Gao, L. Meng, Y. Y. Xue, P. H. Hör, and C. W. Chu, Comparison between the magnetic and transport critical current densities in high critical current density melt-textured yttrium barium copper-oxide Appl. Phys. Lett. vol. 58, pp. 92-94, 1991.
T. A. Friedmann, M. W. Rabin, J. Giapintzakis, J. P. Rice, and D. M. Ginsberg, Direct measurement of the anisotropy of the resistivity in the a-b plane of twin-free, single crystal, superconducting YBajCujO j Phys. Rev. B, vol. 42, pp. 6217-6221, 1990.
F. Sandiumenge, B. Martinez and X. Obradors, Tailoring of micro-structure and critical currents in directionally solidified YBa2Cu3O7 x Supercond. Sei. Technol. vol. 10, pp. A93-A119, 1997.
C. P. Bean, Magnetization of high-field superconductors Rev. Mod. Phys. vol. 1, pp. 31-36,1964.
E. S. Otabe, N. Ohtani, T. Matsushita, Y. Ishikawa, and S. Yoshizawa, Estimation of critical current density in a melt-processed superconducting Y-Ba-Cu-O using AC and DC inductive methods Jpn. J. Appl. Phys. vol. 33, pp. 996-999,1994.
A. M. Campbell, The response of pinned flux vortices to lowfrequency fields J. Phys. C, vol. 2, pp. 1492-1501, 1969.
M. Watahiki, S. I. Yoo, and M. Murakami, A.C. susceptibility measurements in the presence of D.C. magnetic fields for Nd-Ba-CuO superconductors Supercond. Sei. Technol. vol. 10, pp. 754-757, 1997.
Ph. Vanderbemden et al. Superconducting properties of natural and artificial grain boundaries in bulk melt-textured YBCO Physica C, vol. 302, pp. 257-270,1998.
H. Kupfer, C. Keller, K. Salama, and V. Selvamanickam, Inductive current measurements in an oriented grained YBa2Cu3Ox superconductor Appl. Phys. Lea. vol. 55, pp. 1903-1905,1989.
