  We present the irreversibility generated by a stationary cavity
magnomechanical system composed of a yttrium iron garnet (YIG) sphere with a
diameter of a few hundred micrometers inside a microwave cavity. In this
system, the magnons, i.e., collective spin excitations in the sphere, are
coupled to the cavity photon mode via magnetic dipole interaction and to the
phonon mode via magnetostrictive force (optomechanical-like). We employ the
quantum phase space formulation of the entropy change to evaluate the
steady-state entropy production rate and associated quantum correlation in the
system. We find that the behavior of the entropy flow between the cavity photon
mode and the phonon mode is determined by the magnon-photon coupling and the
cavity photon dissipation rate. Interestingly, the entropy production rate can
increase/decrease depending on the strength of the magnon-photon coupling and
the detuning parameters. We further show that the amount of correlations
between the magnon and phonon modes is linked to the irreversibility generated
in the system for small magnon-photon coupling. Our results demonstrate the
possibility of exploring irreversibility in driven magnon-based hybrid quantum
systems and open a promising route for quantum thermal applications.
