Discrete energy spectrum of nonlinear spin ensembles in the ferrimagnet K$_{0.4}$[Cr(CN)$_{6}$][Mn$(R/S)$-$pn$]$(R/S)$-$pn$H$_{0.6}$

Series of spontaneous magnetization jumps have been observed on the background of a continuous relaxation of the magnetic moment of a molecular ferrimagnet in a constant magnetic field. A statistical analysis of the set of data has demonstrated the presence of at least two modes in the distribution of magnetization reversal jumps over their amplitude. It has been found that the number of modes in the distribution depends on the magnetic field and temperature and characterizes a discrete energy spectrum of nonlinear spin ensembles formed at low temperatures. The continuous component of the magnetic relaxation corresponds to the motion of domain-wall arrays in the temperature range from 20 to 50 K and to relaxation processes in the spin-soliton lattice at temperatures ranging from 2 to 10 K.