Crystal structures and magnetic properties of the BaAl4-type structure derivatives in Gd–Al–Ga system

• We study the crystal structure of GdAlxGa4−x compounds with 8–66 at.% Ga.
• Existing range of these compounds is fragmented into seven individual regions.
• The effective magnetic moments have been calculated.
• The excess magnetic moments are caused by the contribution of the non-4f electrons.

The crystal structures of GdAlxGa4−x−v compounds (8–66 at.% Ga, x = 3.6–0.70, v = 0–0.12) were studied by the X-ray diffraction methods (both single crystal and powder diffraction ones). Two new types of structure (monoclinic GdAl3.00Ga0.76 and orthorhombic GdAl2Ga2) were shown to be constructed of two distorted BaAl4-like fragments. Reasoning from the peculiarities of crystal structures, the whole existence region of the GdAlxGa4−x−v compounds is fragmented into seven narrow individual ones (seven compounds). At the temperature range 300–650 K the GdAlxGa4−x−v alloys were shown to be paramagnets with magnetic moments decreasing from 8.07 to 7.84μB with Ga-content increasing.