Collective electromagnetic relaxation in crystals of molecular magnets
  We study the magnetization reversal and electromagnetic radiation due to collective Landau-Zener relaxation in a crystal of molecular magnets. Analytical and numerical solutions for the time dependence of the relaxation process are obtained. The power of the radiation and the total emitted energy are computed as functions of the crystal parameters and the field sweep rate. 
Collin L. Joseph, Carlos Calero, and Eugene M. Chudnovsky