Non-collinear magnetism of Cr, Mn and Fe trimers supported on the non-magnetic metal surface

Self-consistent calculations of Cr, Mn and Fe trimers supported on the non-magnetic metallic substrate were performed using recursion method in the vector Anderson model. In all cases the ground state corresponds to the coplanar ordering of the magnetic moments. Angles between the moments depend on the interatomic distances in trimer. For isosceles trimers two atoms are equivalent and in the ground state the angles θ between their magnetic moments and the moment of the third atom are equal. For the Cr trimer θ decreases from π to π/2 versus the distance d1 between the non-symmetric atoms when the distance d2 between the symmetric atoms is fixed. On the contrary this angle decreases monotonically from π to π/2 versus d2 for fixed d1. For the Fe trimer non-collinear magnetic ordering was found only for small values of d1 and d2. For Mn, which occupies an intermediate position in the periodic table, there is a wide region of d1 and d2 values where the angle between moments equals 2π/3 so that the total magnetic moment of the cluster is practically zero. Finally we point out that the spin–orbit interaction modifies the direction of the magnetisation but not essentially the non-collinearity.