Azimuthal Spin Wave Modes Excited in an Elliptical Nanomagnet With Vortex Pair States

The ferromagnetic thin-film elements can be prepared to form a ¿diamond¿ remanent state that contains two vortices with opposite circulation and with the same or opposite core polarities. The vortex polarity could influence their normal modes through the magnetostatic interactions between two vortices. In this paper, micromagnetic simulations, combined with Fourier techniques, are employed to study the spin-wave (SW) modes excited in a submicron Permalloy ellipse with a vortex pair configuration. After the application of an inplane Gaussian field pulse, it is found that a series of azimuthal SW modes is excited and the high-order harmonics of SW modes are strongly dependent of the core polarities due to the dynamic magnetic interactions between the two vortices.