Electronic structure and enhancement of magnetic moments in the ferromagnetic nitride Fe16N2.

Abstract

The electronic structure of ${\mathrm{Fe}}_{16}$${\mathrm{N}}_{2}$ is calculated by using the linear muffin-tin orbital method in the atomic-sphere approximation (LMTO-ASA). Both the standard local-spin-density approximation (LSDA) and the recently proposed generalized gradient approximation (GGA) are used in this density functional calculation. By introducing the gradients of the density, the exchange-correlation effect is taken into account more sufficiently in GGA than in LSDA. Magnetic moments at three different sites of Fe atom (i.e., Fe I, Fe II, Fe III) are 2.20, 2.55, and 2.70${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$, respectively. Larger enhancement of magnetic moment is obtained in Fe II and Fe III, which are located farther from N than Fe I. There is no significant difference in magnetic moments and density of states between the two approaches (GGA and LSDA).