Lattice Parameter and Its Pressure Dependence of High Tc SrxLa2-xCuO4-y (x∼0.6) Prepared under Reducing Condition

Abstract

Lattice parameters of superconducting Sr _x La_2-x CuO_4-y (x∼0.6) with T _c onset above 50 K prepared under a reducing condition and pressure dependence of the parameters have been studied. By reducing treatment, the lattice parameter c ₀ at ambient pressure was shortened from 13.25 to 13.20 Å and T _c onset was increased from below 10 K to above 50 K. For the high T _c specimen, compressibility along c-axis was larger than that along a-axis. These results suggest that the high T _c specimen with Sr content x of about 0.6 has a large amount of oxygen vacancies which are likely to be created in vertical sites of CuO₆ clusters in K₂NiF₄ structure.