New quadruple perovskite Gd2Ba2Ti2Cu2O11: a potential superconducting parent phase

Abstract

The compound Gd₂Ba₂Cu₂Ti₂O₁₁ has been synthesized by reaction of the component oxides at 1025 °C and its structure refined from powder X-ray diffraction data. The material crystallises with a quadrupled perovskite unit cell, similar to that of La₂Ba₂Cu₂Sn₂O₁₁ containing alternating double layers of copper and titanium. A reduction in the copper–oxygen distance in the CuO₂ planes from 2.007 Å in La₂Ba₂Cu₂Sn₂O₁₁ to 1.951 Å in Gd₂Ba₂Cu₂Ti₂O₁₁ produces a copper–oxygen interaction similar to that found in high-temperature superconductors.