Raman scattering signatures of strong spin-phonon coupling in the bulk magnetic van der Waals material CrSBr

Magnetic excitations in layered magnetic materials that can be thinned down to the two-dimensional (2D) monolayer limit are of great interest from a fundamental point view and for applications. Raman scattering has played crucial role exploring properties and, even though it is essentially probe lattice vibrations, reflect ordering solids through spin-phonon interaction or observation magnon excitations. In bulk CrSBr, $A$-type antiferromagnet (AF), we show directly observed temperature dependence response (i) variations scattered intensities, (ii) activation new phonon lines reflecting change symmetry with appearance additional periodicity, (iii) below N\'eel $({T}_{N})$ second-order processes. We additionally three different phases encountered including recently identified low-temperature phase, have particular signature. This work demonstrates CrSBr in-plane magnetization provide unique insight into materials.