Microwave Permeability of FeCo-Based Magnetic Thin Films

Magnetic FeCoSiB thin films have been prepared and annealed at 300 °C and 400 °C for 1 hour. The as-prepared films and films annealed at 300 °C are found in amorphous states and to be anisotropic in static magnetic properties. Nanocrystalline grains have been found in the films annealed at 400 °C, which are isotropic in magnetic properties. With increasing the annealing temperature, the coercivity and saturation magnetic fields are found decreasing. The resonance frequency shows the same varying trend as the saturation magnetic fields. Large microwave magnetic losses have been found in all the films, which indicate that these films have potential applications in microwave noise attenuation.