P(2X2) VERSUS C(2X2) CONFIGURATIONS FOR ONE MN MONOLAYER ON FE(001)

The spin polarization of a Mn monolayer on Fe(001) and the interfacial magnetic coupling have been investigated using the tight-binding line ar muffin-tin orbital method. We have studied five spin configurations for the Mn monolayer and found that the two lowest in energy, namely c(2 x 2) and p(2 x 2)up arrow (the up-arrow up arrow indicates that th e magnetization of the Mn layer points in the same direction than the Fe substrate one), are nearly degenerate. These two configurations lea d to different interfacial magnetic couplings and mean surface magneti zations. This result sheds some Light onto recent contradictory experi mental data.