STATISTICAL-THEORY OF THERMAL MIXING OF NUCLEAR ZEEMAN AND ELECTRON-SPIN SPIN RESERVOIRS

The regular nuclear spin system that interacts with the diluted system of paramagnetic impurities is considered. The method of concentration expansion of the memory function is used for the calculation of the spectral density of the correlation function <S(z)(t) S(z)> at high- and low-temperature ranges of the impurity spin reservoir. The thermal contact of this system with the nuclear Zeeman system is studied in two cases: the absence of nuclear spin diffusion and rapid nuclear spin diffusion. The inhomogeneous widening of electron paramagnetic (EPR) line is taken into account at the limit of rapid spectral diffusion.