Modeling High-Frequency Magnetic Losses in Transverse Anisotropy Amorphous Ribbons

The superior high-frequency magnetic behavior of transverse anisotropy amorphous ribbons can be qualitatively interpreted in terms of rotation dominated magnetization process and quantitatively predicted describing the spin dynamics by the Landau-Lifshitz-Gilbert (LLG) equation in association with the electromagnetic diffusion equation. The theory is applied to comprehensive measurements performed on Co-based alloys, tested as field-annealed tapewound rings from dc to 1 GHz with combination of fluxmetric and transmission line methods. The LLG equation is numerically solved considering the role of magnetostatic, exchange, anisotropy, eddy current, and applied fields. It accurately describes the high-frequency energy losses, ensuing from eddy currents, and spin damping. By further considering the low-frequency domain wall contribution, a full scenario for the broadband losses is achieved.