Raman Light Scattering from Excitons and Magnons in Cobalt Fluoride

We have observed one-particle, inelastic, polarized light scattering from low-lying excitons and magnons in single-crystal cobalt fluoride (Co${\mathrm{F}}_2$) at 2°K. Because of the orbital nature of these excitations, the cross sections (${10}^{-33\mathrm{}}$-${10}^{-32\mathrm{}}$ ${\mathrm{cm}}^2$/sr) are much larger than for one-magnon scattering in the other case, which has been measured (Fe${\mathrm{F}}_2$, ∼${10}^{-35\mathrm{}}$ ${\mathrm{cm}}^2$/sr). Our measured cross sections are in good agreement with a recent calculation by Ishikawa and Moriya.