Abstract
We have investigated the structure, defect concentration, and superconducting properties of by neutron powder diffraction, thermogravimetric analysis, and ac susceptibility. Samples with three oxygen contents and ’s ranging from 135 to 94 K, obtained through different annealing conditions, were studied. Two defect sites were observed in all samples. The concentration of defect oxygen atoms located at a site in the center of the Hg- plane, is found to vary from 0.18(2) to 0.10(2) oxygen atoms per formula unit as decreases from 135 to 94 K. An additional defect, which we interpret as oxygen atoms associated with the substitution of Cu on the Hg site, is found to have a fixed concentration of ∼0.09(2) oxygen atoms per formula unit.
- Received 15 August 1994
DOI:https://doi.org/10.1103/PhysRevB.51.15407
©1995 American Physical Society