Comparison of the superconducting properties of Y-Ba-Cu-O and Y-Ba-Cu-O-Ag bulk superconductors

Abstract

The widespread use of RE-Ba-Cu-O [(RE)BCO] bulk superconductors, where RE=Y, Gd or Sm, in practical applications requires large single grains that exhibit uniform superconducting properties. Until recently, however, it was difficult to grow successfully YBCO-Ag bulk materials in the required single grain form, due primarily to the relative complexity of the top seeded melt growth process (TSMG) and the introduction of an alloying element (Ag) to the precursor composition. In most cases, alloying elements are used to improve the mechanical properties of the bulk superconductor whilst, at the same time, aim to cause minimal detrimental effect on the superconducting properties of the fully processed sample. In this work we investigate the effect of the addition of silver to YBCO on the superconducting properties of the bulk single grain, including trapped field, T c and J c, and on the sample microstructure.