Magnetic and Crystallographic Studies on Rare Earth Germanides

Abstract

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 RGe 2 (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; DyGe 1.62 with the C 32 type of structure (the low temperature phase), DyGe 1.62 with the C c type of structure (the high temperature one), and GdGe 1.67 and DyGe 1.67 with the C c type of structure. Compounds RGe 2 (R=Gd, Tb, Dy, Ho), RGe 1.67 (R=Gd, Dy), and DyGe 1.62 , become antiferromagnetic at low temperatures. Compounds NdGe 2 and PrGe 2 are ferromagnetic as reported previously. Compounds SmGe 2 and ErGe 2 are paramagnetic above 4.2°K. The Néel temperature of TbGe 2 is 42°K, which is the highest among those of heavy rare earth germanides.