抄録
Crystallographic and magnetic studies have been made on germanides of rare earth metals Nd, Pr, Sm, Gd, Tb, Dy, Ho, and Er in the composition range near 1:2. The compound RGe2 (R=Gd, Tb, Dy) has an orthorhombic crystal structure, of which the atomic arrangement is unknown. Through the crystallographic survey, four non-stoichiometric phases have been found; DyGe1.62 with the C32 type of structure (the low temperature phase), DyGe1.62 with the Cc type of structure (the high temperature one), and GdGe1.67 and DyGe1.67 with the Cc type of structure. Compounds RGe2 (R=Gd, Tb, Dy, Ho), RGe1.67 (R=Gd, Dy), and DyGe1.62, become antiferromagnetic at low temperatures. Compounds NdGe2 and PrGe2 are ferromagnetic as reported previously. Compounds SmGe2 and ErGe2 are paramagnetic above 4.2°K. The Néel temperature of TbGe2 is 42°K, which is the highest among those of heavy rare earth germanides.
