Parametric magnon-driven anisotropic spin pumping

Abstract

We explore the effect of magnetic anisotropy on the interplay between spin current and parametric instability in magnetization dynamics, crucial for developing efficient nonlinear spintronics devices. The parametric instability is induced by the Suhl process where a uniform mode magnon excites two counter-propagating parametric magnons. We experimentally demonstrate direction-specific spin current generation via spin pumping from these parametrically excited magnons in a thin bilayer of [110]-oriented yttrium iron garnet and platinum (Pt), utilizing the facet-dependent magnetocrystalline anisotropy and magnetodipolar interaction. The facet-symmetry and the shape anisotropy modulate the magnonic dispersion relation as well as the magnon-scattering process which determines the spin pumping efficiency. Analyzing the in-plane angular dependence of spin pumping-induced inverse spin Hall effect voltage, we demonstrate anisotropic control of the spin pumping efficiency of the parametric magnons. Our findings provide critical insights to enhance control in magnonic logic devices.