Competing structural and magnetic effects in small iron clusters

We present new results of ab initio total-energy calculations of small iron clusters, Fen with 2 ⩽ n ⩽ 15, in which structural Jahn-Teller like distortion and competing non-collinear and collinear magnetic moments have been taken care of simultaneously. We used the density-functional method that employs pseudopotentials and the projector augmented wave method. The full relaxation of the atoms without imposing any symmetry constraints leads to unsymmetrical arrangements of the atoms (distorted clusters) and restores collinearity of the magnetic moments of all clusters considered so far. For n ⩽ 7 our results agree in part with previous ab initio calculations.