Spin wave modes of width modulated Ni_(80)Fe_(20)/Pt nanostrip detected by spin-orbit torque induced ferromagnetic resonance

摘要

We study magnetic dynamics of Ni_(80)Fe_(20)/Pt magnonic crystals made of width periodically varied nanostrips using the spin-torque induced ferromagnetic resonance technique. DC voltage signals are detected when nanostrip magnonic crystals (MCs) are driven resonantly. The DC voltage originates dominantly from the spin rectification effect due to the coupling between the AC electrical current and the oscillated anisotropic magnetoresistance. In addition to uniform magnetization precession across the MC, localized spin wave modes are also observed. Their evolution with the strength and direction of the magnetic field are studied. Micromagnetic simulations are performed to illustrate the experimental results.