Amplification of small signals near the threshold of a collective-acoustic instability in a system of parametric nuclear magnons

Amplification of small signals was observed in a system of parametric nuclear magnons in antiferromagnetic CsMnF3 near the threshold of excitation of elastic vibrations of the crystal. This effect confirmed the predictions of Wiesenfeld and McNamara of the behavior of a dynamic system near a cycle creation bifurcation. A calculation of coupled oscillation of the magnon and phonon subsystems of a crystal, carried out using a model of a collective-acoustic instability proposed by Cherepanov, provided a satisfactory description of the experimental results