The maser effect in a paramagnetic crystal caused by the thermal action of the spin system aided by a pulsed magnetic field

A theoretical and experimental investigation is carried out of the maser effect at the spin sublevels of Co-59(2+) ions in a Co-59(2+):Ce(3+):La2Mg3(NO3)12-24H2O crystal in the three-centimeter band. In contrast to paramagnetic amplifiers with microwave or optical pumping, the quantum amplification comes directly from the energy of the phonons of the crystal, which is immersed in liquid helium. The EPR spectrum and the kinetics of the spectral transitions of Co(2+) ions under conditions of thermal excitation are studied, and determinations are made of the most important kinetic and thermodynamic parameters of the spin system.