Abstract
A new mercury based superconductor (Hg1-ySey)(Sr2-xLax)CuO4+delta (y = 0.25: 0.3 <= x <= 0.7) with a T-c(onset) of 50 K has been synthesized using sol-gel process combined with the sealed quartz tube method. X-ray diffraction shows that the (Hg0.75Se0.25)(Sr2-xLax)CuO4+delta phase crystallizes in the tetragonal symmetry (space group P-4/mmm) with a approximate to ap approximate to 3.8 angstrom and c approximate to 8.7 angstrom and is isostructural with the 94 K superconductor HgBa2CuO4+delta, adopting the so-called 1201-type structure. Both Se and La are necessary for the stabilization of the 1201-type Hg/Sr cuprates. EDX analysis indicated that mercury and selenium have incorporated into the structure with Se/Hg approximate to ?. The new high-T-c superconductor, (Hg0.75Se0.25)(Sr1.3La0.7) CuO4+delta, exhibits a current density, J(c). of 1270 KA/cm(2) at (5 K and 5 T) which is higher than the estimated J(c) value for (Hg,Cr)Sr2CuO4+delta. (C) 2008 Elsevier B.V. All rights reserved.