Structure and soft magnetic properties of Fe-Zr-N films

Abstract

Soft magnetic films with high saturation magnetization and controllable uniaxial anisotropy are required for future high frequency applications. However, the origin and magnitude of the induced magnetic anisotropy are still a contradictory issue. In this paper we show the influence of the structure and composition of sputtered Fe-Zr-N films upon the coercivity and the induced uniaxial magnetic anisotropy. We have found that the increase of the nitrogen content of the sputtered films leads to a reduction of the grain size and a strong increase of the uniaxial anisotropy. The value of 20 Oe for the anisotropy field combined with a saturation magnetization of 20 kG found in a film with average grain size as low as 10 nm gives a ferromagnetic resonance frequency of 1.8 GHz and a roll-off frequency of 1.2 GHz. Such a film is a promising candidate to be used as an ultra-high frequency inductor.