Evidence of enhanced pinning properties in optimally doped Bi2Sr2Ca1minus;xYxCu2O8+dgr;thinsp;single crystals

摘要

A comparative study of the magnetic properties of Bi2Sr2Ca1minus;xYxCu2O8+dgr;single crystals with different yttrium contents is presented. An optimum in the doping can be reached that corresponds to a highTc(onset) value (91.5 K) and a high position of the irreversibility line. Moreover, the fishtail feature disappears for this optimally Y doped Bihyphen;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 highestTc. copy;1996 American Institute of Physics.