Crystal structure and magnetic properties of GdSi_(1.78), Gd(Si_(0.684)Ge_(0.316))_(1.78), GdGe_(1.57), and GdSn_2 compounds

摘要

Intermetallic compounds of Gd with Si, Ge, and Sn near 1:2 stoichiometry adopt several closely related crystal structures. We find that GdSi_(1.78) and Gd(Si_(0.684)Ge_(0.316))_(1.78) crystallize in the same GdSi_(1.4)-type orthorhombic structure (space group Imma), while GdGe_(1.57) and GdSn_2 adopt α-ThSi_2-type tetragonal structure (space group I4_1/amd) and ZrSi_2-type orthorhombic structure (space group Cmcm), respectively. All compounds order antiferromagnetically; their Neel temperatures are only weakly affected by the magnetic field of less than 50 kOe. Unusual features are observed including multiple phase transitions and thermomagnetic irreversibilities.