| Résumé | Light scattering studies of magnetic compounds provide spectral information on magnetic excitations such as the magnons and on lattice vibrations. In particular cases, the phonon and magnetic excitations show evidence of direct symmetry-allowed coupling, but more often the spin-phonon interaction is observed less obviously in the Raman spectrum of the phonons. The phonon intensity, frequency and linewidth may be modified by the exchange interaction between magnetic ions. A summary of the light scattering work on spin-phonon coupling in magnetic solids is given in COTTAM and LOCKWOOD. Theories for the spin dependence of the zero wavevector optic phonon frequencies, and the corresponding Raman intensities, have been proposed by several authors. Much of the work is either phenomenological or has been applied specifically to ferromagnets of the EuO and CdCr2Se4 structures. |
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