Magnetodielectric coupling of infrared phonons in single crystal Cu$_{2}$OSeO$_{3}$

TL;DR

This study investigates the magnetodielectric coupling in Cu$_{2}$OSeO$_{3}$ by measuring its infrared optical properties across temperatures, revealing phonon behavior linked to magnetic transition effects.

Contribution

It provides the first detailed analysis of infrared phonon modes and their magnetodielectric coupling in Cu$_{2}$OSeO$_{3}$ using optical spectroscopy and modeling.

Findings

Identification of phonon modes exhibiting anomalous behavior near T_c

Observation of a magnetodielectric effect around 60 K

Detailed assignment of infrared phonon modes in the material

Abstract

Reflection and transmission as a function of temperature have been measured on a single crystal of the magnetoelectric ferrimagnetic compound Cu$_{2}$OSeO$_{3}$ 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. The fits of the infrared phonons show a magnetodielectric effect near the transition temperature ($T_{c}\sim 60$~K). Assignments to strong far infrared phonon modes have been made, especially those exhibiting anomalous behavior around the transition temperature.