Nanocrystalline Fe-Co-Ni-B thin film with high permeability and high-frequency characteristics

To develop magnetic materials with high magnetic moment and good high-frequency characteristics, Fe-Co-B and Fe-Co-Ni-B thin films were fabricated by RF magnetron sputtering. On adding Ni to Fe-Co-B system, the soft magnetic properties of Fe-Co-Ni-B film were improved, which resulted from the microstructural changes of the films. The Fe-Co-Ni-B films with a thickness of 100-300 nm exhibited 4πMs of 17-22 kG, Hc in hard axis of ∼1 Oe, ρ of 70-110μΩcm, and Hk of 32-43 Oe.