Optical detection of magnetic orders in HgCr$_2$O$_4$ frustrated spin magnet under pulsed high magnetic fields

TL;DR

This study uses magneto-optical techniques to detect magnetic orders in HgCr₂O₄ under pulsed high magnetic fields, revealing phase transitions and magnetic ordering phenomena in frustrated spin systems.

Contribution

It demonstrates the effectiveness of optical detection methods for magnetic phase transitions in HgCr₂O₄ under high magnetic fields, expanding understanding of frustrated spin magnets.

Findings

Intensity changes in optical spectra match magnetization and lattice distortion data.

Detection of the last-ordered magnetic phase before full polarization.

Similar magnetic phase behavior observed as in other chromium spinel oxides.

Abstract

A magneto-optical survey was conducted for HgCr$_2$O$_4$ powder samples under pulsed high magnetic fields of up to 55 T. Intensity changes in magnetic fields observed for the exciton-magnon-phonon optical transition spectra coincide well with those of magnetization, lattice distortion from X-ray diffraction, and electron-magnetic resonances. The last-ordered phase was detected prior to the fully polarized magnetic phase, similarly to the other chromium spinel oxide, ZnCr$_2$O$_4$ and CdCr$_2$O$_4$.