XANES study on the evolution among different copper species, Cu-I, Cu-II and Cu-III, in CuBa2YCu2O6+z upon oxygen loading
Journal
Journal of Low Temperature Physics
Journal Volume
131
Journal Issue
3-4
Pages
381-386
Date Issued
2003
Author(s)
Abstract
X-ray absorption near-edge structure (XANES) spectroscopy at the Cu L-edge is applied to follow the gradual formation of CuII and CuIII species from the Cu1 species with increasing amount of excess oxygen, z, in Cu(1) Ba2 Y Cu(2 2 O6+z. For the study, a series of samples with precisely controlled oxygen contents was prepared utilizing the temperature-controlled oxygen-depletion (TCOD) annealing technique in the sample synthesis and employing coulometric titration for accurate oxygen-content analysis. It may be concluded that at low amounts of excess oxygen, z, Cu(1)I in the charge-reservoir tends to be first oxidized to Cu(1)II rather than directly to Cu(1 )III, suggesting that complete chain formation does not occur at low oxygen contents.
Type
journal article