Evidence of enhanced pinning properties in optimally doped Bi2Sr2Ca1−<i>x</i>Y<i>x</i>Cu2O8+δ  single crystals

Abstract

A comparative study of the magnetic properties of Bi2Sr2Ca1−xYxCu2O8+δ single crystals with different yttrium contents is presented. An optimum in the doping can be reached that corresponds to a high Tc (onset) value (91.5 K) and a high position of the irreversibility line. Moreover, the fishtail feature disappears for this optimally Y doped Bi-2212 crystal due to the increase of the magnetic field dependence of the critical current density. This demonstrates the better pinning efficiency of the crystals with the highest Tc.