Magnetic and Structural Characterization of NiFe/Fe30Co70 Bilayers

Magnetostrictive films are required for a wide range of device applications; by increasing the magnetostriction constant and decreasing the anisotropy field, the devices will become more efficient. This paper has studied Fe
₃₀
Co
₇₀
films on different thicknesses of the soft magnetic underlayer Ni
₈₁
Fe
₁₉
, to determine how the structural and magnetic properties change. It was found that the anisotropy field of the Fe
₃₀
Co
₇₀
film could be reduced by 50% to 10 kA/m and the magnetostriction constant increased by a factor 4 to 65 ppm when grown on 30 nm Ni
₈₁
Fe
₁₉
. This was due to the NiFe underlayer inducing a BCC(110) texture within the Fe
₃₀
Co
₇₀
film and reducing the in-plane stress.