Infrared investigation of the phonon spectrum in the frustrated spin cluster compoundFeTe2O5Cl

Abstract

We present our optical investigations on the frustrated spin cluster compoundFeTe2O5Cl, which develops a long-range antiferromagnetic order below 10 K. We measure the opticalreflectivity from the far-infrared to the ultraviolet with polarized light. We focus ourattention on the lattice dynamics by discussing the infrared-active modes. Our findingsreveal a polarization dependence of the vibrational modes but which do not seem to beaffected by structural anomalies linked to the magnetically ordered state at lowtemperatures.