TERNARY MANGANESE COMPOUNDS AMNX (A = MG, CA, SR OR BA X = SI, GE OR SN) - CHARACTERIZATION OF THE MAGNETIC-PROPERTIES BY NEUTRON-DIFFRACTION EXPERIMENTS

Neutron diffraction experiments led to the determination of the antife rromagnetic spin structures of MgMnGe, CaMnSi, CaMnGe, CaMnSn, SrMnGe, SrMnSn, and BaMnGe. For the compounds MgMnGe, CaMnSi, CaMnGe, and CaM nSn an arrangement was found that can be described in the crystallogra phic cell; in the case of SrMnGe, SrMnSn, and BaMnGe the c-axes have t o be doubled. The Shubnikov-groups are P4'/n'm'm and P4'/n'cc', respec tively. The magnetic moments of the maganese atoms are significantly b elow those values to be expected for Mn2+ ions.