Distinct magnetic states of metastable fcc structured Fe and Fe-Cu alloys studied by ab initio calculations

Based on the projector augmented wave method within the generalized gradient approximation, ab initio calculations predict five distinct magnetic states of Fe in fee structure depending sensitively on their atomic volumes, i.e., with increasing the atomic volume, there appears firstly a complicated coexistence of a non-magnetic, two antiferromagnetic, and a low spin ferromagnetic states, and then a high spin ferromagnetic state. Moreover, the present calculations also predict that the high spin ferromagnetic state of Fe atoms could be stabilized in some nonequilibrium Fe-Cu alloys over a relatively broad composition range, suggesting a possible approach to synthesize new Fe-containing alloys of high performance in magnetization. An intensive discussion is accompanied to compare the predictions with those from experiments as well as from those calculated results reported previously. It turns out that the present calculations could give reasonable interpretation to the richness and/or the complexity of the magnetic behaviors of fee Fe and the Fe-Cu alloys. (c) 2005 Elsevier B.V. All rights reserved.