Theoretic 3-D study of the high-frequency magnetic moment dynamics in thin ferromagnetic films with in-plane uniaxial anisotropy by considering eddy-current generation

Abstract In the present paper, theoretic investigations of polarisation vector precession trajectories represented by a macro spin in ferromagnetic films with in-plane uniaxial anisotropy were realised. For this purpose, the Landau–Lifschitz–Gilbert differential equation (LLG) in combination with the Maxwell equations were solved for three dimensions by considering a linear progression of the magnetisation or polarisation with an external field. The frequency and time dependent polarisation trajectories illustrate how a magnetic moment precesses if effective damping and eddy-currents impacts its motion. For computation, typical parameter values like the saturation polarisation Js=μ0·Ms=1.4 T and in-plane uniaxial anisotropy μ0·Hu=4.5 mT were employed. The main focus of simulation was on the variation of the effective damping parameter αeff between 0.01 and 0.05 and ferromagnetic film thickness tm between 200 nm and 1200 nm. The frequency-dependent calculations were carried out between 50 MHz and 6 GHz. The time-dependent simulations were done for a duration between 5 and 30 ns.