The synthesis of layered cuprates with nonmagnetic and fixed oxidation state cations separating the Cu-O planes has, until now, led to nonsuperconducting materials. A new series of layered copper oxides with the general formula LnSr2Cu2GaO7 (Ln = La-Yb, Y) has been synthesized. The structure has been studied by both powder neutron diffraction and single-crystal X-ray analysis. The typical unit cell is a ≈ 22.8 Å, b ≈ 5.5 Å, c ≈ 5.4 Å, in space group Ima2 (No. 46). The structure is closely related to that of YBa2Cu3O7 and can be described as replacement of the square-planar copper with a tetrahedral gallium. The larger lanthanides are distributed unevenly over the two A-cation sites, whereas the smaller lanthanides occupy the site between the cuprate planes. We have been able to introduce superconductivity in the Y-Sr-Cu-Ga-O system by appropriate doping with calcium and annealing.
|Number of pages||6|
|Journal||Chemistry of Materials|
|Publication status||Published - 1991|
ASJC Scopus subject areas
- Materials Chemistry
- Materials Science(all)