One- and two-magnon and exciton Raman scattering in antiferromagnetic CoF2: Experiment and theory

Experimental data are reported for the temperature and polarization dependence of the oneand two-magnon Raman light scattering in the rutile-structure antiferromagnet CoF2. The correspondingn Stokes and anti-Stokes Raman spectra are measured, emphasizing the temperature and polarization variations of the one-magnon frequency, line width, and integrated intensity. A Green's function method is employed to derive the excitation energies and their intensities over a broad range of temperatures (below the N,el temperature = 38 K) for a spin S = 3/2 anisotropic antiferromagnet with strong spin-orbit coupling. The exchange terms are analyzed using the random-phase approximation while single-ion anisotropy terms are treated exactly by generating a closed set of coupled Green's function equations. Good overall agreement between theory and experiment is obtained.