Phys.org October 28, 2023
In some non- and paramagnetic systems, a large phonon magnetic moment is found due to coupling with electronic excitations. However, for magnetically ordered systems, a correspondingly large moment has not yet been discovered, and the roles of many-body correlations and fluctuations in phonon magnetism remain unclear. Researchers in China found a phonon magnetic moment that was enhanced by critical fluctuations in Fe2Mo3O8. Combining magneto-Raman spectroscopy and inelastic neutron scattering measurements, they showed that a pair of low-lying chiral phonons carried large magnetic moments. Once the system was driven to a ferrimagnetic phase, they observed a splitting between the chiral phonons of nearly a quarter of the phonon frequency and observed a sixfold enhancement in the phonon magnetic moment in the vicinity of the Néel temperature. According to the researchers microscopic model based on the coupling between phonons and both magnons and paramagnons accounts for the experimental observations… read more. TECHNICAL ARTICLEÂ
Schematic diagram of ferrimagnetic fluctuation enhanced phonon magnetic moment… Credit: Wu et al. Credit: Nature Physics, 14 September 2023