Manipulation of bistability through the coupling strength in cavity magnon polaritons

Abstract

Benefiting from the latest experiment of non-linearity in cavity magnon polaritons due to the magnetocrystalline anisotropy in the yttrium iron garnet (YIG) crystal, we theoretically propose a cavity magnonics model that can be used to study the bistable behaviors by changing the coupling strength, which presents the rich and interesting phenomena. In the case of resonance, the critical driving powers of the upper and lower polariton modes have the smaller values for the larger coupling strength but the larger values for the smaller coupling strength. In addition, the upper and lower polariton modes show the repulsive and attractive features, respectively, when the derivative of the coupling strength with respect to the position of the YIG sphere changes from positive to negative. Especially, the bistability of the lower polariton mode disappears when the driving power is strong enough. Our research broadens the means of manipulation of non-linearity in cavity magnon system, which provides a promising application for cavity spintronics and information processing.