High-frequency behavior of electrodeposited Fe-Co-Ni alloys

The high-frequency properties (permeability, resonance frequencies, damping parameters) of electrodeposited Fe-Co-Ni films with different composition and structure were studied by ferromagnetic resonance (FMR) and high-frequency permeability measurements. Soft, high-moment films with small grain size and limited easy axis dispersion exhibit resonance frequencies above 2 GHz. The behavior of these films can be well described by existing phenomenological theories, and the high-frequency properties measured by the two methods are in agreement. On the contrary, the high-frequency characteristics of films with a large dispersion of the uniaxial anisotropy derived from FMR data and permeability measurements using conventional phenomenological correlations are not in agreement; the behavior of these films cannot thus be described by existing theories.