Spin-wave mode coupling in the presence of the demagnetizing field in cobalt-permalloy magnonic crystals.

We present the results of studies on the non-uniform frequency shift of spin wave spectrum in a two-dimensional magnonic crystal of cobalt/permalloy under the influence of external magnetic field changes. We investigate the phenomenon of coupling of modes and, as a consequence, their hybridization. By taking advantage of the fact that compressing the crystal structure along the direction of the external magnetic field leads to an enhancement of the demagnetizing field, we analyse its effect on the frequency shift of individual modes depending on their concentration in Co.

Vortex polarization dynamics in a square magnetic nanodot.

Langevin simulations at finite temperature of two-dimensional magnetic nanodots were performed using the Landau-Lifshitz equation with exchange and dipolar interactions. In a wide range of temperatures, the dynamics of square samples with one central vortex was studied, focusing on the out-of-plane magnetic component at the vortex-core. This vortex-core undergoes polarization sign reversals in a thermally activated process.