  Spectra of one-electron and collective excitations in narrow-band
ferromagnets with unquenched orbital moments are calculated in various
theoretical models. The interaction of spin and orbital excitations with
conduction electrons results in the damping of the former which, however, turns
out to be rather small; therefore, apart from usual spin waves, well-defined
orbitons can exist. Non-quasiparticle states occur in the electron energy
spectrum near the Fermi energy due to this interaction. The criteria of
stability of the saturated spin and orbital ferromagnetic ordering are
considered. Possible effects of orbital ordering in magnetite and in colossal
magnetoresistance manganites are discussed.
