Preparation and magnetic property of new rare earth compounds R2GeBe2O7 (R = La,Pr, Sm,Gd, Dy,Er) and Y2GeBe2O7

New rare earth compounds which are isostructural with silicate minerals of the melilite family have been prepared. The cell dimensions vary linearly with the radii of rare earth ions, showing a typical Lanthanoid contraction. Magnetic susceptibilities of the rare earth compounds were measured in the temperature range from 77 K to 1000 K. A trend toward weak ferromagnetism with decreasing temperature was observed in the heavy rare earth compounds.