Parametric Pair of Waves as a Nonlinear Oscillator

We considered the process of parametric excitation of spin waves and magnetoelastic waves in magnetoordered crystals in a microwave resonator. From our analysis it follows that for the k and -k wave pair there is a single-mode realization (i.e. the pair can be represented as one oscillator). The theory of parametric resonance of waves constructed in terms of these collective variables provides a new perspective on some old spin-wave experiments and helps explain the recently obtained experimental data.