Effect of iron doping and oxygen stoichiometry on infrared absorption in Y₁Ba₂Cu₃O_7-δ

Abstract

We report infrared absorption of Y₁Ba₂Cu₃O_7-δ as a function of oxygen stoichiometry (0 < δ < 1) and copper substitution by iron in the spectral range of 450-700 cm⁻¹. The strong bands associated with Cu-O vibrations undergo significant changes in their frequencies and intensities as δ is varied across the orthorhombic to tetragonal phase. These changes coupled with those arising as a result of doping with iron has helped in identifying the nature of the vibrational modes.