Effect of Ca Content on the Critical Current Density and Flux Pinning Properties of Ag Sheathed Bi-2212 Tapes

Single filament Ag sheathed Bi2.1Sr1.96CaxCu2O8+delta (Bi-2212) tapes with different Ca content of x=0.90, 0.95, 1.00, and 1.05, were prepared by powder in tube (PIT) process. The critical current density and flux pinning properties have been systematically studied with the variation of Ca content. X-ray diffraction (XRD) and scanning electron microscopy (SEM) have been performed for the characterization of the tapes. Although the maximum critical current density, J(c), was obtained from the stoichiometric sample under zero field, the nonstoichiometric Ca content are beneficial for the improvement of J(c) under magnetic field, due to the enhancement of flux pinning. The J(c) value of 950 A/cm(2) has been obtained at 0.15 T, which is over 30% higher than that from x=1.00 tape. (C) 2012 Published by Elsevier B. V. Selection and/or peer-review under responsibility of the Guest Editors.