  In this work, we studied the local structure and the magnetization of Co4N
thin films deposited by a reactive dc magnetron sputtering process. The
interstitial incorporation of N atoms in a fcc Co lattice is expected to expand
the structure and such expansion yields interesting magnetic properties
characterized by a larger than Co magnetic moment and a very high value of spin
polarization ratio in Co4N. By optimizing the growth conditions, we prepared
Co4N film having lattice parameter close to its theoretically predicted value.
The N concentration was measured using secondary ion mass spectroscopy.
Detailed magnetization measurements using bulk magnetization method and
polarized neutron reflectivity confirm that the magnetic moment of Co in Co4N
is higher than that of Co.
