Improvement of soft magnetism of Fe90Co10 sputtered films by addition of N and Ta

The addition of Ta and N into sputtered Fe90Co10 alloy films was performed to attain soft magnetism with large saturation magnetization 4πMs. Addition of Ta below 8 at. % to Fe90Co10 films improved their crystallinity and the lattice constant of Fe crystallites was expanded. These films revealed relatively large 4πMs of about 21 kG. The deposition of Fe–Co and Fe–Co–Ta films at N2 partial pressure PN2 below 0.1 m Torr was so effective as to cause fine granulation in the film. Fe84.6Co8.4Ta7:N films deposited at PN2 of about 0.2 mTorr and postannealed at 150 °C revealed 4πMs and relative permeability μr of about 16 kG and 1500, respectively.