Raman scattering in ferromagnetic TDAE-C₆₀ compared to TDAE-C₇₀

The Raman scattering at 1.16 eV laser excitation has been studied in ferromagnetic TDAE-C₆₀ and compared to that in paramagnetic TDAE-C₇₀. The shift of H_g and A_g modes in TDAE-C₆₀ indicates transfer of one electron to C₆₀ while the broadening of H_g modes is quite similar to metallic K₃C₆₀ meaning significant electron-phonon coupling of this Jahn - Teller vibrations. In TDAE-C₇₀ the lines are narrow sugesting suppresed electron - phonon interaction and hence smaller polaronic effects. Below T_c of magnetic ordering the two-magnon excitations are not seen clearly however the low energy part of spectra shows somewhat increased intensity. Upon air-exposure of TDAE-C₆₀ all H_g and A_g Raman modes disappear while a new band appears at 1848 cm^-1.