Crystal chemistry and magnetic properties of ternary compounds REAgxGa3−x (RE = Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu)

The crystal structure of LuAg1.2Ga1.8 was determined from single-crystal X-ray diffraction data (structure type β-YbAgGa2, space group Pnma, a = 6.8821(4) Å, b = 4.2695(2) Å, c = 10.1268(5) Å, RF = 0.029, RW = 0.031 for 595 unique reflections and 28 variables). Applying X-ray powder diffraction, the new compounds REAgxGa3−x (RE = Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu) were found to be isostructural. They possess homogeneity ranges at 873 K with x values between 1.04 and 1.35. From magnetic susceptibility data the compounds REAgxGa3−x (RE = Sm, Gd, Tb, Dy, Ho, Er, Tm) are paramagnets and order antiferromagnetically at low temperatures, while LuAgxGa3−x is a diamagnet.