Growth and characterization of YBa<inf>2</inf>(Cu<inf>1-X</inf>A<inf>X</inf>)<inf>3</inf>O<inf>7-δ</inf> (A = Mg, Zn, Ni) bars as switching elements for fault current limiters

Single domain melt textured YBCO ceramics have a high interest as switching elements for fault current limiters. The high amount of energy accumulated in the hot spot together with the low thermal conductivity leads to material damage. A reduction of the critical current density (JC) is a way to minimise the accumulated energy in the hot spot. Our approach for the reduction of the JC is to dope the material to lower the TC. Single domain melt textured bars have been obtained by the Bridgman method with different dopants. Pulsed currents have been applied to the samples in order to study the quench current that induces transition to the normal state. This measurements show that with the appropriate dopant level, and thus, by tuning the optimal JC, it is possible to get a transition of the 100% of the superconducting volume. © 2002 Elsevier Science B.V. All rights reserved.