Decay rates for the magneto-micropolar system in $$varvec{L^2(}pmb {mathbb {R}}^{varvec{n)}}$$

In this paper, the large time decay of the magneto-micropolar fluid equations on (mathbb {R}^n) (( n=2,3)) is studied. We show, for Leray global solutions, that ( Vert ({varvec{u}},{varvec{w}},{varvec{b}})(cdot ,t) Vert _{{L^2(mathbb {R}^n)}} rightarrow 0 ) as (t rightarrow infty ) with arbitrary initial data in ( L^2(mathbb {R}^n)). When the vortex viscosity is present, we obtain a (faster) decay for the micro-rotational field: ( Vert {varvec{w}}(cdot ,t) Vert _{{L^2(mathbb {R}^n)}} = o(t^{-1/2})). Some related results are also included.