The solid solution Gd 1– x Y x Ag 2 Mg

Abstract The Heusler phases GdAg 2 Mg and YAg 2 Mg form a continuous solid solution Gd 1– x Y x Ag 2 Mg. Samples were prepared in steps of x = 0.1 and characterized by powder X-ray diffraction and temperature dependent magnetic susceptibility measurements. The a lattice parameter decreases in a Vegard-type manner from GdAg 2 Mg to YAg 2 Mg. The crystal structure of Gd 0.577(7) Y 0.423 Ag 2 Mg was refined from single-crystal X-ray diffractometer data: F m 3 ̅ m , a = 697.33(7) pm, w R = 0.0386, 69 F 2 values and six variables. The rare earth atoms are coordinated by a cube of silver atoms ( bcc superstructure) with (Gd/Y)–Ag distances of 302 pm. The continuous substitution of gadolinium ( T C = 98.3(5) K) by yttrium keeps (i) the stable trivalent ground state of gadolinium and (ii) the long-range ferromagnetic ordering, however, with a continuous decrease of the Curie temperature with increasing yttrium content. The ferromagnetic ordering in the sample with the lowest gadolinium content, Gd 0.1 Y 0.9 Ag 2 Mg, sets in below 2.6 K. The magnetization isotherms classify the Gd 1– x Y x Ag 2 Mg samples as soft ferromagnets.