ELECTRONIC-STRUCTURE AND ENHANCEMENT OF MAGNETIC-MOMENTS IN THE FERROMAGNETIC NITRIDE FE16N2

The electronic structure of Fe16N2 is calculated by using the linear m uffin-tin orbital method in the atomic-sphere approximation (LMTO-ASA) . Both the standard local-spin-density approximation (LSDA) and the re cently proposed generalized gradient approximation (GGA) are used in t his density functional calculation. By introducing the gradients of th e 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 mu(B), respectively. Larger enhancement of magnetic moment is obtained in Fe II and Fe III, which are located farther from N than Fe I. Ther e is no significant difference in magnetic moments and density of stat es between the two approaches (GGA and LSDA).