Roles of Excess Atoms in Electronic and Magnetic Properties of Fe_2+<i>x</i>V_1-<i>x</i>Z (Z = Al, Ga)

Abstract

To expand our knowledge of Fe 2+ x V 1- x Z (Z = Al, Ga), band calculations (LMTO-ASA) have been performed for several x values ( x =0, ±0.125, ±0.25) with a supercell method. Obtained density of states and magnetic moments indicate that excess atoms, which are introduced instead of the original Fe or V atom in Fe 2 VZ, bring a drastic change in electronic and magnetic properties of Fe 2 VZ. The existence of those atoms causes the collapse of the gap (or pseudogap) and the change from nonmagnetic to magnetic states. In the magnetic state, those atoms carry 2.5–2.6µ B for x >0 and 0.7–1.1µ B for x <0.