Phonon superradiance and phonon laser effect in nanomagnets
  We show that the theory of spin-phonon processes in paramagnetic solids must take into account the coherent generation of phonons by the magnetic centers. This effect should drastically enhance spin-phonon rates in nanoscale paramagnets and in crystals of molecular nanomagnets. 
E. M. Chudnovsky and D. A. Garanin