Critical current density of SmBCO coated conductor on IBAD-MgO substrate fabricated by co-evaporation

Abstract

We have fabricated SmBCO coated conductor on IBAD-MgO substrates using unique co-evaporation method. The batch type co-deposition system was specially designed and was named EDDC (evaporation using drum in dual chamber) that is possible to deposit superconducting layer with optimum composition ratio of materials at temperature over 700 degrees C and several mTorr of oxygen. In this study, we have investigated the influence of SmBCO phase composition ratio on the critical current density of coated conductor. We have optimized the composition ratio by changing the deposition rates of Ba and Cu during co-evaporation for better critical current density. A higher critical current density was measured at the composition ratio of Ba deficiency (1.9-2.0) and Cu rich (3.2-3.4) compared to the Sm1Ba2Cu3Oy , stoichiometry. Especially, highest critical current density of 2.6 MA/cm(2) was measured at the composition of Sm1Ba1.9Cu3.2Oy that has dense surface morphology. (C) 2007 Elsevier B.V. All rights reserved.