Incoherent interaction of propagating spin waves with precessing magnetic moments

Abstract

The magnetization dynamics of the magnetic vortex state occurring in response to subnanosecond transitions of the externally applied magnetic field was investigated in Ni[subscript 80]Fe[subscript 20](12 nm)/Ir[subscript 80]Mn[subscript 20](5 nm) square elements by exploiting time-resolved scanning Kerr microscope and micromagnetic modeling. Upon application of a magnetic field pulse the magnetization undergoes a precessional oscillation of ∼2 GHz while the magnetic vortex core moves from the equilibrium position. Along the pathway of the moving core, strong bursts of spin waves are generated by the creation and subsequent annihilation of a vortex-antivortex pair. An abrupt suppression of magnetization precession occurs subsequently after a vortex-antivortex core annihilates. The observed suppression is attributed to the incoherent interaction of precessing magnetic moments with propagating spin waves. The experimental observations are qualitatively well reproduced by micromagnetic modeling.