Infrared spectroscopy on Y1−xRExBa2Cu3−yZnyO6 (RE Pr, Gd, x = 0 and 0.8; y = 0 and ≈ 0.15)

Abstract Far- and mid-infrared properties of antiferromagnetic Y 1− x RE x Ba 2 Cu 3− y Zn y O 6 (RE  Pr, Gd, x = 0 and y = 0 and ≈ 0.15) were investigated by infrared reflection and transmission measurements ( κ ∥ c -axis). All six phonon modes of E u symmetry and several multi-phonon bands were observed. Zn substitution causes phonon side bands and a surprising temperature dependence of multi-phonon bands, possibly due to spin-lattice interactions. All compounds show several features in the mid-infrared range that might be related to bimagnon-plus-phonon absorption.