Hybridization Reduction of the magnetization for N doped FeCo superlattices

초록

In search of a soft magnetic material exhibiting high magnetization, we investigated the magnetic and structural properties of an (Fe3Co)4N superlattice (SL) with (m=2) and without (m=0) N doping via first principles full-potential linearized augmented plane wave calculations in order to examine the possible magnetic enhancement by (i) N addition (which has drawn considerable attention since the first report (in 1972) of a giant magnetic moment for quasistable ″-Fe16N2) and (ii) the lowered dimensionality of the SL. The structural optimization was fully accomplished by total energy and atomic force calculations within the generalized-gradient approximation. Despite the lattice expansion by 9% due to the N insertion, the magnetization of (Fe3Co)4N2 was found to be reduced from the value of the Fe3Co superlattice by the strong hybridization of N with Fe and Co.