On the long-range magnetic order and the preferred spin orientation of the layered magnetic oxides Sr2MnSi2O7 and Ba2MnGe2O7

The causes for the three-dimensional magnetic ordering and the observed spin orientation of the layered oxides Sr2MnSi2O7 and Ba2MnGe2O7 were investigated by evaluating the spin exchange interactions and the preferred spin orientation on the basis of density functional calculations and by calculating the magnetic dipole–dipole interaction energies.