Dependence of soft magnetic properties and high frequency characteristics on film thickness for Ni75Fe25–ZnO nano-granular films

(Ni75Fe25)69(ZnO)31 granular films with various thicknesses were deposited by magnetron co-sputtering. The dependence of soft-magnetic properties and high frequency characteristics on film thickness was investigated systematically. Static magnetic research exhibits that thin films showed evident in-plane uniaxial magnetic anisotropy. And an interesting phenomenon was found that the magnetic anisotropy field Hk increases with increasing film thickness t, which is not found in previous reports. However, no obvious variation with film thickness t was found for the coercivity (Hce) in easy axis and the coercivity (Hch) in hard axis. The measurements of high frequency characteristics show that the ferromagnetic resonance frequency fr increases with increasing film thickness t, which is ascribed to the increase of the magnetic anisotropy field Hk. The films fabricated with appropriate thickness exhibits good high frequency properties and can be applied in the sensors operated in high frequency range.