Ferromagnetic resonance studies of Fe16N2 films with a giant magnetic moment

Abstract

The g factor and 4π M_s for epitaxially grown Fe₁₆N₂(001)/In_0.2Ga_0.8As(001) films have been investigated by ferromagnetic resonance along with Fe films for comparison. Angular dependence of the resonance fields in the film plane of Fe₁₆N₂ films had four‐fold symmetry, which was attributed to the in‐plane anisotropy. The g factor for Fe₁₆N₂ films was about 2.0, which means that the magnetic moment originates mainly from spin. Thus, nothing unusual is seen about the g factor. The g factor for Fe films was about 2.1, which is very similar to the value reported previously. 4πM_s values for Fe₁₆N₂ and Fe films were 2.8×10⁴ and 2.1×10⁴ G, respectively, which agree well with the previous data obtained by a vibrating sample magnetometer. This confirmed that Fe₁₆N₂ has a giant magnetic moment. Torque magnetometer measurements showed that Fe₁₆N₂ films have a larger perpendicular anisotropy of 7.8×10⁶ erg/cm³, which can originate from its bct structure.