Complex magnetic behavior at the surface of B2 ordered FeCr alloy

Bouzar et al. (1997) have recently investigated the surface of B2 FeCr alloy. In all cases of crystal growth 0 0 1, 1 1 0 and 1 1 1 they found the local polarization at the surface to be antiferromagnetically coupled with the subsurface layer in contrast to parallel coupling between Fe and Cr in bulk FeCr. In order to assert these results, we have investigated the local polarization of Fe at the (0 0 1) surface of this alloy with a tight-binding linear muffin tin Orbitals (TB-LMTO) model. Using general gradient approximation with Langreth-Mehl-Hu functional for p(1 × 1) and c(2 × 2) configurations we found the local polarization at the Fe surface layer to be antiferromagnetically coupled with the subsurface Cr layer and high magnetic moments compared to the bulk values.