Magnetic-order induced phonon splitting in MnO from far-infrared spectroscopy

TL;DR

This study investigates how magnetic order influences phonon splitting in MnO using far-infrared spectroscopy, revealing temperature-dependent phonon behavior and comparing experimental results with theoretical predictions.

Contribution

It provides detailed experimental data on phonon splitting in MnO and compares these findings with recent theoretical models of spin-phonon coupling.

Findings

Phonon splitting occurs at the antiferromagnetic transition.

Temperature affects phonon eigenfrequencies and damping.

Results support spin-driven Jahn-Teller effect models.

Abstract

Detailed far-infrared spectra of the optical phonons are reported for antiferromagnetic MnO. Eigenfrequencies, phonon damping and effective plasma frequencies are studied as a function of temperature. Special attention is paid to the phonon splitting at the antiferromagnetic phase transition. The results are compared to recent experimental and theoretical studies of the spin-phonon coupling in frustrated magnets, which are explained in terms of a spin-driven Jahn-Teller effect, and to ab initio and model calculations, which predict phonon splitting induced by magnetic order.