Investigation of nonequilibrium processes of magnetoelastic waves and evidence of their BEC formation in an antiferromagnetic system

The canted antiferromagnet FeBO₃ exhibits strong nonlinear interactions between magnetoelastic waves that can manifest as a variety of interesting phenomena. We show that excited magnetoelastic waves and their quanta, which we refer to as mexons, exhibit a wide range of nonequilibrium nonlinear wave phenomena including mode competition under noisy pumping, full submission to external coherent fields, and evidence of quasi-equilibrium Bose-Einstein condensation (BEC) at room temperature. The mode we suggest as the mexon BEC exhibits extremely high efficiency with a quality factor of Q ~ 8x10⁵. Remarkably, this behavior occurs in a system that is very near its transition temperature due to the heat generated by microwave pumping. Our results suggest that such systems can be of technological importance due to the uniqueness of the mode quality and ability to modulate external signals, as well as from the standpoint of studying a whole class of nonlinear wave phenomena usually taking place in a wide range of environments and conditions.