PREPARATION, STRUCTURE, AND MAGNETIC-PROP ERTIES OF THE ALKALINE-EARTH MANGANESE COMPOUNDS AMNX WITH A = MG, CA, SR, BA AND X = SI, GE, SN

The new compounds MgMnGe, MgMnSn, CaMnSi, CaMnSn, and SrMnSn were prep ared by reaction of the elements. They crystallize tetragonally with t he anti-PbFCl type structure (space group P4/nmm). The lattice constan ts see ''Inhaltsubersicht''. Using a Faraday balance, magnetic measure ments in the range 4.2 to 800 K were performed with the new substances and with the already known compounds CaMnGe, SrMnGe, and BaMnGe. They indicate metamagnetic behaviour at low temperatures. At high temperat ures twodimensional magnetic interactions between the manganese atoms seem to persist. The construction of an unexpensive heating device for the Faraday balance is described.