Upper critical field of gold-doped YBa2Cu3O7-δ

Specimens of YBa2Cu3O7-δ containing 2.2 at. % Au were prepared using a zone-melting technique. Optical microscopy, x-ray lattice parameter, and fluorescence measurements were used to characterize the morphology and gold content of the specimens. A comparison of the values of the reversible magnetization leads to the conclusion that the upper critical field in the Au-doped specimens is significantly lower than in undoped samples prepared in an identical fashion. © 1993 The American Physical Society.