Spin-phonon and magnetostriction phenomena in CaMn7O12 helimagnet probed by Raman spectroscopy

TL;DR

This study uses Raman spectroscopy to explore how magnetic and structural phase transitions in CaMn7O12 influence phonon behavior, revealing spin-phonon coupling and magnetostriction effects at different temperatures.

Contribution

It provides new insights into the temperature-dependent spin-phonon and magnetostriction phenomena in CaMn7O12 using Raman spectroscopy.

Findings

Anomalies in Raman modes at magnetic transitions

Evidence of spin-phonon coupling at higher temperatures

Detection of magnetostriction effects at lower temperatures

Abstract

In this letter we investigated the temperature-dependent Raman spectra of CaMn7O12 helimagnet from room temperature down to 10 K. The temperature dependence of the Raman mode parameters show remarkable anomalies for both antiferromagnetic and incommensurate transitions that this compound undergoes at low temperatures. The anomalies observed at the magnetic ordering transition indicate a spin-phonon coupling at higher-temperature magnetic transition in this material, while a magnetostrinction effect at the lower-temperature magnetic transition.