  Spin-charge-lattice coupling mediated by multi-magnon processes is
demonstrated in multiferroic BiFeO3. Experimental evidence of two and three
magnons excitations as well as multimagnon coupling at electronic energy scales
and high temperatures are reported. Temperature dependent Raman experiments
show up to five resonant enhancements of the 2-magnon excitation below the Neel
temperature. These are shown to be collective interactions between on-site Fe
d-d electronic resonance, phonons and multimagnons
