New Oxygen-Deficient Perovskite Phase, La1-xSrxCuO3-y (0.20≦x≦0.25)

Abstract
In a given system, a new nonstoichiometric perovskite solid solution was found to exist in a narrow range of 0.20≦x≦0.25. This perovskite phase has a tetragonal distortion based on a Jahn-Teller effect of the Cu ion. The lattice parameters are closely related to those of the simple cubic perovskite: a=10.834(1) Å, c=3.8638(4) Å for La0.75Sr0.25CuO2.44 and a=10.851(1) Å, c=3.8623(6) Å for La0.80Sr0.20CuO2.47, where a≃2√2c. These perovskites are metallic conductors and no superconducting transition has been observed in a measured temperature range of 77–300 K.