GOLD SUBSTITUTION IN HGBA2CA2CU3O8-CRYSTALS(DELTA SINGLE)

We have synthesized single crystals of Hg1-xAuxBa2Ca2Cu3O8+delta (Hg(A u)-1223) a with nominal Au content in the range 0 less than or equal t o x less than or equal to 0.20. The composition and the homogeneity of the crystals were studied by election microprobe analyses and the lat tice constants were determined by X-ray diffraction. The nominal compo sition of gold of x = 0.05 corresponds to an optimum for growing stoic hiometric Hg-1223 single crystals. Each individual crystal shows a hom ogeneous gold content but the amount of substitution varies from 0.08 to 0.14 from crystal to crystal. These crystals exhibit superconductiv ity at T-c= 133 K. (C) 1998 Elsevier Science B.V.