FERROMAGNETIC-RESONANCE STUDIES OF FE16N2 FILMS WITH A GIANT MAGNETIC-MOMENT

The g factor and 4pi M(s) for epitaxially grown Fe16N2(001)/In0.2Ga0.8 As(001) films have been investigated by ferromagnetic resonance along with Fe films for comparison. Angular dependence of the resonance fiel ds 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 fac tor for Fe films was about 2. 1, which is very similar to the value re ported previously. 4piM(s) values for Fe16N2 and Fe films were 2.8 X 1 0(4) and 2.1 X 10(4) G, respectively, which agree well with the previo us data obtained by a vibrating sample magnetometer. This confirmed th at Fe16N2 has a giant magnetic moment. Torque magnetometer measurement s showed that Fe16N2 films have a larger perpendicular anisotropy of 7 .8 X 10(6) erg/cm3, which can originate from its bct structure.