Tracing magnetic bubble evolutions in two-dimensional van der Waals magnets using magneto-Raman spectroscopy

We combine cryogenic Lorentz transmission electron microscopy with magneto-Raman spectroscopy to investigate the interplay between spin-phonon coupling and spin textures in a two-dimensional (2D) van der Waals magnet. When stable skyrmion bubbles are formed in the 2D magnet, we observe a field-dependent Raman shift that is absent when the 2D magnet is prepared in its ferromagnetic state. By numerically calculating the field-dependent spin distributions of the skyrmion bubbles and correlating them with the spin-phonon coupling, we find qualitative agreements between the numerical model and experimental results. We therefore assign the Raman shift to field-induced modulations of the skyrmion bubbles.