Investigation of infrared phonon modes in multiferroic single-crystal FeTe${}_2$O${}_5$Br

Abstract

Reflection and transmission as a function of temperature (5--300 K) have been measured on single crystals of the multiferroic compound FeTe${}_2$O${}_5$Br utilizing light spanning the far infrared to the visible portions of the electromagnetic spectrum. The complex dielectric function and optical properties were obtained via Kramers-Kronig analysis and by fits to a Drude-Lortentz model. Analysis of the anisotropic excitation spectra via Drude-Lorentz fitting and lattice dynamical calculations have lead to the observation of all 52 IR-active modes predicted in the $ac$ plane and 43 or the 53 modes predicted along the b axis of the monoclinic cell. Assignments to groups (clusters) of phonons have been made and trends within them are discussed in light of our calculated displacement patterns.

9 pages, 7 figures

References in corpus (8)

• Ferroelectricity in the Magnetic E-Phase of Orthorhombic Perovskites
• Dual nature of improper ferroelectricity in a magnetoelectric multiferroic
• Direct transition from a disordered to a multiferroic phase on a triangular lattice
• Manipulating the magnetic structure by electric fields in multiferroic ErMn2O5
• Magnetic-order induced phonon splitting in MnO from far-infrared spectroscopy
• Spin amplitude modulation driven magnetoelectic coupling in the new multiferroic FeTe${}_2$O${}_5$Br
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Cited by in corpus (2)

• Use of X-ray scattering functions in Kramers-Kronig analysis of reflectance
• Infrared dielectric properties of low-stress silicon oxide