We have systematically performed x-ray absorption spectroscopic (XAS) studies on the new mercuric halide intercalated superconductors, (HgX₂)_0.5Bi₂Sr₂CaCu₂O_y with X equals Br and I, in order to investigate the electronic and crystal structure of these compounds. The present Hg L_III-edge EXAFS results indicate that the mercury is coordinated with two bromide or iodide ligands with bond length of 2.46 angstrom for the HgBr₂-intercalate and 2.65 angstrom for the HgI₂-one. This is the first example of linear molecular salt of HgX₂ stabilized in the solid lattice. According to the I L_I- and Br K-edge x-ray absorption near edge structure (XANES) spectroscopic studies, a small amount of electron transfer from the intercalant HgX₂ to the host lattice could be observed upon intercalation, resulting in the negatively charged state of (HgX₂)^(delta -). The Cu K-edge EXAFS analysis reveals that the bond distance of Cu-O_axial is slightly shortened upon intercalation, reflecting the oxidation of (Cu-O) layer, which is well consistent with the I L_I- and Br K-edge XANES results.

Date Published: 10 June 1996
PDF: 6 pages
Proc. SPIE 2696, Spectroscopic Studies of Superconductors, (10 June 1996); doi: 10.1117/12.241786

Published in SPIE Proceedings Vol. 2696:
Spectroscopic Studies of Superconductors
Ivan Bozovic; Dirk van der Marel, Editor(s)