Phenomenological theory of superradiation from crystals of high-spin molecules is suggested. We show that radiation friction can cause a superradiation pulse and investigate the role of magnetic anisotropy, external magnetic field, and dipole-dipole interactions. Depending on the contribution of all these factors at low temperature, several regimes of magnetization of crystal sample are described. Very fast switch of magnetization’s direction for some sets of parameters is predicted.

• Received 3 April 2003

DOI:https://doi.org/10.1103/PhysRevB.68.144420